Aesthetic Dermatology

Lasers have become a critical part of the dermatologist’s armamentarium for modulating cutaneous biology, both in treating skin disorders and providing tangible cosmetic alterations to the skin. Although advances in technology and convenient user interfaces have made modern lasers relatively straightforward to use, they are in fact quite complex and powerful instruments that are capable of considerable damage if not used correctly. Thus it is necessary to establish a framework for the safe and responsible use of lasers in dermatology; fundamental to this tenet is an understanding of the development and physics of lasers. In this article, the fundamental concepts of lasers as well as their interactions with the skin will be discussed to impart a working knowledge of lasers to allow for better, safer use of these important tools.

Development of Lasers

The term laser is an acronym for “light amplification by the stimulated emission of radiation.” Albert Einstein established the framework for the functioning of lasers in his seminal work, “On the Quantum Theory of Radiation,”¹ in which he described how an electron in an atom in an excited state can return to a lower state by emitting energy in the form of a photon of light. Light comprises a portion of the electromagnetic spectrum, rangingfrom UV (200–400 nm) to visible (400 to about 700 nm) to infrared light (about 700 to >3000 nm). The unique properties of light that affect the function of lasers include reflection (eg, seeing a mirror image of a mountain on the surface of a still lake) and refraction (eg, your hand looking larger under the surface of a pool of water).

Despite early theories on lasers, it was not until the late 1950s that the technology finally started to catch up to the science. Researchers experimenting with microwave fields were able to generate a beam of excited ammonia molecules through a resonant cavity, resulting in a uniform (albeit low power) emission of radiation.² Maiman³ expounded on this development by building the first working prototype of a device that radiated light without the use of a microwave. So how exactly do lasers work?

Basic Physics of Lasers

To understand how lasers work, one must have a rudimentary understanding of quantum mechanics. Bohr⁴ revealed that an atom is comprised of a nucleus that is orbited by electrons at discrete distances (ie, only at specific radii), which have corresponding energy levels that increase as the distance from the nucleus increases. With the application of energy, an electron may be excited to a higher energy level, thus increasing its distance from the nucleus, but will then spontaneously return to the lower energy level. By the law of conservation of energy, the excess energy is released as a photon. Although this small amount of energy would not be of much interest at the single particle level, Einstein and Bose discovered that photons were uniquely “gregarious” with the tendency to join together in a common state, leading to the ability to generate a coherent beam of light by simultaneously exciting multiple atoms and their electrons, whereby the return of one electron to a lower energy state generated a chain reaction among the other excited electrons, subsequently prompting the release of photons with the same characteristics as the initial incident photon and returning to a lower energy state.⁵ This process requires several steps to occur in order. First, absorption of energy has to occur among a population of atoms, thus exciting the electrons to higher energy states. When one of the electrons returns to a lower energy level, spontaneous emission will occur with the release of a photon of light. The photon has a certain probability of colliding with other atoms, thereby causing their electrons to return to a lower energy state and release additional photons of light with the same wavelength and in the same direction as the incident photon in a process that is referred to as stimulated emission.⁶ When this process occurs in a cavity with a large number of atoms, the result may lead to a high-energy beam of photons, which becomes the laser beam.

There are some caveats to consider regarding electron population dynamics as outlined by the Boltzmann principle whereby only a small proportion of molecules are in the first excited state and the vast majority are in the ground state (lowest energy) at any given time, but the details of higher-energy transitions in quantum mechanics are beyond the scope of this article.⁷ Primarily, it is important to understand that the ultimate power of a laser’s output depends largely on the population of electrons that are residing at a higher energy state at any given point in time, and the goal of many types of lasers is to achieve a large number of electrons in a high-energy state as opposed to their usual ground state, a process known as population inversion.⁸

This process leads to the fundamental construction of a laser: a population of atoms in a resonant cavity flanked by reflectors that are exposed to some sort of excitation mechanism (known as the pump) with an output mechanism for the laser beam to exit. In practice, the material used to supply the atoms (known as the gain medium) varies and also determines the wavelength and properties of the laser beam due to differences in the discrete energy states of orbiting electrons. Whatever the gain medium being used, the important properties of a laser resulting from these principles is that the beam is monochromatic (consisting of a single wavelength or a very narrow band), coherent (the light is emitted in the same phase and direction), collimated (a narrow beam diameter with limited divergence), and intense (high power per unit area). Consider the differences between a laser pointer and a flashlight; from across the room, the laser pointer output is a small spot of light on the wall whereas the flashlight has long dispersed to a weak, broad swath of light.

Types of Lasers

Different gain media have been used to create a variety of lasers with different properties. In general, lasers fall into 1 of 4 categories: gas discharge, diode, dye, and solid-state lasers.⁹

Although a gas discharge laser theoretically is the simplest laser, whereby a gas is excited by an electric discharge and the excited particles of gas create the laser beam, there are practical considerations such as excessive heat production, which may necessitate the use of cooling coils or some other method for heat dispersion. The excimer laser is a specific type of gas discharge laser in which a noble gas is mixed with halogen and high-current pulses are used to generate excited dimers, hence the term excimer. The excited dimers consisting of 1 halogen molecule and 1 noble gas molecule are only linked in the excited state, thus allowing for more stability in the excited state and enabling a higher proportion of molecules to be in that state at any given time, which increases population inversion and thus helps to maximize the output energy.

Diode lasers employ the use of diodes, or semiconductors that allow current to flow in one direction but not the other (theoretically with infinite resistance in one direction and no resistance in the other direction), thus creating a downstream method to achieve a high-power laser output; however, despite its theoretical efficiency, the use of diode lasers has been limited due to practical considerations of the divergence and quality of the output.

Dye lasers consist of a liquid solution of organic dye in a solvent that is pumped by an optical source. While gas discharge lasers involve excitation of a gas, there is a clear corollary with dye lasers with liquid taking the place of the gas; however, this modality has certain limitations, including the use of toxic materials that degrade naturally; the need to switch cuvettes when changing gain media, which serve as the lasing medium; and a relatively low-power output. One benefit of the dye laser, as alluded to above, is the operator’s capability to switch out cuvettes containing different dyes, thus using one machine to generate widely varying laser beams.

Solid-state lasers are most often used in dermatology. These devices utilize a conducting medium (eg, garnet, sapphire, ruby) doped with trivalent rare-earth ions or transition metal ions (eg, neodymium, ytterbium, erbium, titanium, chromium). This process is a relatively reliable and flexible methodology for generating stable lasers, thus explaining its widespread use. Additionally, these solid-state lasers are particularly amenable to modifications (eg, Q-switching).

Considerations for Lasers

Quality switching (known as Q-switching) is a method used to generate a shorter burst of a higher-power laser output.¹⁰ The longer the electrons have to become excited within a resonant cavity, the higher the number that may end up in an excited state, thus allowing for a higher ultimate energy output to a certain point. The quality of a medium, in general, refers to the ability of light exiting a medium to return. Within a cavity, the ability of light to go back and forth through the lasing medium is critical in achieving stimulated emission and thus laser beam output; however, in a low-quality medium, population inversion can still occur to allow a greater proportion of electrons to reside in a higher energy state. There are multiple mechanisms to switch the quality of a medium, but the ultimate result always is for the quality to be switched to high so that the light beams can immediately start achieving stimulated emission of a “primed” population of high-energy, population-inverted electrons, resulting in a much higher output power.

Selective thermolysis is critical for understanding modern laser use. To fully comprehend its meaning, one must first understand that the interaction of a laser with the skin depends on a number of factors, including the power density of the laser itself (the beam characteristics), the length of time of exposure, and the physical properties of the targeted molecules. Although there is some modulation of laser function via the wavelength of the laser (eg, higher wavelengths penetrate deeper), the properties of the target molecule can allow for precise control of the laser’s action. The framework for understanding this principle was outlined by Anderson and Parrish¹¹ in 1983. Fundamentally, a laser causes damage to a target molecule via application of large amounts of energy; however, the laser beam does not discriminate between different molecules in its path. Rather the size and other properties of the molecule play a critical role in determining the amount of energy it is able to absorb before dissipating the excess energy as heat. This excess heat energy is what causes damage to surrounding tissues, or collateral damage. Conceptually, being able to target a molecule without damaging surrounding tissues is our goal as practitioners when using lasers in dermatology. It is accomplished by heating a molecule to just under its thermal relaxation time (ie, the time needed for a molecule to dissipate half of the energy applied), thus allowing for acceptable results with regard to efficacy balanced with side effects.¹²

Conclusion

Lasers are an important treatment modality, and their use in dermatology is becoming widespread for many possible indications; however, lasers are complex mechanical devices that have the potential to cause great harm when used incorrectly. By gaining a thorough understanding of the basic physics of lasers, the different types of lasers that are available, and critical concepts regarding the cutaneous application of lasers, physicians can better understand these devices and approach their use confidently and safely.

Lasers have become a critical part of the dermatologist’s armamentarium for modulating cutaneous biology, both in treating skin disorders and providing tangible cosmetic alterations to the skin. Although advances in technology and convenient user interfaces have made modern lasers relatively straightforward to use, they are in fact quite complex and powerful instruments that are capable of considerable damage if not used correctly. Thus it is necessary to establish a framework for the safe and responsible use of lasers in dermatology; fundamental to this tenet is an understanding of the development and physics of lasers. In this article, the fundamental concepts of lasers as well as their interactions with the skin will be discussed to impart a working knowledge of lasers to allow for better, safer use of these important tools.

Development of Lasers

The term laser is an acronym for “light amplification by the stimulated emission of radiation.” Albert Einstein established the framework for the functioning of lasers in his seminal work, “On the Quantum Theory of Radiation,”¹ in which he described how an electron in an atom in an excited state can return to a lower state by emitting energy in the form of a photon of light. Light comprises a portion of the electromagnetic spectrum, rangingfrom UV (200–400 nm) to visible (400 to about 700 nm) to infrared light (about 700 to >3000 nm). The unique properties of light that affect the function of lasers include reflection (eg, seeing a mirror image of a mountain on the surface of a still lake) and refraction (eg, your hand looking larger under the surface of a pool of water).

Despite early theories on lasers, it was not until the late 1950s that the technology finally started to catch up to the science. Researchers experimenting with microwave fields were able to generate a beam of excited ammonia molecules through a resonant cavity, resulting in a uniform (albeit low power) emission of radiation.² Maiman³ expounded on this development by building the first working prototype of a device that radiated light without the use of a microwave. So how exactly do lasers work?

Basic Physics of Lasers

To understand how lasers work, one must have a rudimentary understanding of quantum mechanics. Bohr⁴ revealed that an atom is comprised of a nucleus that is orbited by electrons at discrete distances (ie, only at specific radii), which have corresponding energy levels that increase as the distance from the nucleus increases. With the application of energy, an electron may be excited to a higher energy level, thus increasing its distance from the nucleus, but will then spontaneously return to the lower energy level. By the law of conservation of energy, the excess energy is released as a photon. Although this small amount of energy would not be of much interest at the single particle level, Einstein and Bose discovered that photons were uniquely “gregarious” with the tendency to join together in a common state, leading to the ability to generate a coherent beam of light by simultaneously exciting multiple atoms and their electrons, whereby the return of one electron to a lower energy state generated a chain reaction among the other excited electrons, subsequently prompting the release of photons with the same characteristics as the initial incident photon and returning to a lower energy state.⁵ This process requires several steps to occur in order. First, absorption of energy has to occur among a population of atoms, thus exciting the electrons to higher energy states. When one of the electrons returns to a lower energy level, spontaneous emission will occur with the release of a photon of light. The photon has a certain probability of colliding with other atoms, thereby causing their electrons to return to a lower energy state and release additional photons of light with the same wavelength and in the same direction as the incident photon in a process that is referred to as stimulated emission.⁶ When this process occurs in a cavity with a large number of atoms, the result may lead to a high-energy beam of photons, which becomes the laser beam.

There are some caveats to consider regarding electron population dynamics as outlined by the Boltzmann principle whereby only a small proportion of molecules are in the first excited state and the vast majority are in the ground state (lowest energy) at any given time, but the details of higher-energy transitions in quantum mechanics are beyond the scope of this article.⁷ Primarily, it is important to understand that the ultimate power of a laser’s output depends largely on the population of electrons that are residing at a higher energy state at any given point in time, and the goal of many types of lasers is to achieve a large number of electrons in a high-energy state as opposed to their usual ground state, a process known as population inversion.⁸

This process leads to the fundamental construction of a laser: a population of atoms in a resonant cavity flanked by reflectors that are exposed to some sort of excitation mechanism (known as the pump) with an output mechanism for the laser beam to exit. In practice, the material used to supply the atoms (known as the gain medium) varies and also determines the wavelength and properties of the laser beam due to differences in the discrete energy states of orbiting electrons. Whatever the gain medium being used, the important properties of a laser resulting from these principles is that the beam is monochromatic (consisting of a single wavelength or a very narrow band), coherent (the light is emitted in the same phase and direction), collimated (a narrow beam diameter with limited divergence), and intense (high power per unit area). Consider the differences between a laser pointer and a flashlight; from across the room, the laser pointer output is a small spot of light on the wall whereas the flashlight has long dispersed to a weak, broad swath of light.

Types of Lasers

Different gain media have been used to create a variety of lasers with different properties. In general, lasers fall into 1 of 4 categories: gas discharge, diode, dye, and solid-state lasers.⁹

Although a gas discharge laser theoretically is the simplest laser, whereby a gas is excited by an electric discharge and the excited particles of gas create the laser beam, there are practical considerations such as excessive heat production, which may necessitate the use of cooling coils or some other method for heat dispersion. The excimer laser is a specific type of gas discharge laser in which a noble gas is mixed with halogen and high-current pulses are used to generate excited dimers, hence the term excimer. The excited dimers consisting of 1 halogen molecule and 1 noble gas molecule are only linked in the excited state, thus allowing for more stability in the excited state and enabling a higher proportion of molecules to be in that state at any given time, which increases population inversion and thus helps to maximize the output energy.

Diode lasers employ the use of diodes, or semiconductors that allow current to flow in one direction but not the other (theoretically with infinite resistance in one direction and no resistance in the other direction), thus creating a downstream method to achieve a high-power laser output; however, despite its theoretical efficiency, the use of diode lasers has been limited due to practical considerations of the divergence and quality of the output.

Dye lasers consist of a liquid solution of organic dye in a solvent that is pumped by an optical source. While gas discharge lasers involve excitation of a gas, there is a clear corollary with dye lasers with liquid taking the place of the gas; however, this modality has certain limitations, including the use of toxic materials that degrade naturally; the need to switch cuvettes when changing gain media, which serve as the lasing medium; and a relatively low-power output. One benefit of the dye laser, as alluded to above, is the operator’s capability to switch out cuvettes containing different dyes, thus using one machine to generate widely varying laser beams.

Solid-state lasers are most often used in dermatology. These devices utilize a conducting medium (eg, garnet, sapphire, ruby) doped with trivalent rare-earth ions or transition metal ions (eg, neodymium, ytterbium, erbium, titanium, chromium). This process is a relatively reliable and flexible methodology for generating stable lasers, thus explaining its widespread use. Additionally, these solid-state lasers are particularly amenable to modifications (eg, Q-switching).

Considerations for Lasers

Quality switching (known as Q-switching) is a method used to generate a shorter burst of a higher-power laser output.¹⁰ The longer the electrons have to become excited within a resonant cavity, the higher the number that may end up in an excited state, thus allowing for a higher ultimate energy output to a certain point. The quality of a medium, in general, refers to the ability of light exiting a medium to return. Within a cavity, the ability of light to go back and forth through the lasing medium is critical in achieving stimulated emission and thus laser beam output; however, in a low-quality medium, population inversion can still occur to allow a greater proportion of electrons to reside in a higher energy state. There are multiple mechanisms to switch the quality of a medium, but the ultimate result always is for the quality to be switched to high so that the light beams can immediately start achieving stimulated emission of a “primed” population of high-energy, population-inverted electrons, resulting in a much higher output power.

Selective thermolysis is critical for understanding modern laser use. To fully comprehend its meaning, one must first understand that the interaction of a laser with the skin depends on a number of factors, including the power density of the laser itself (the beam characteristics), the length of time of exposure, and the physical properties of the targeted molecules. Although there is some modulation of laser function via the wavelength of the laser (eg, higher wavelengths penetrate deeper), the properties of the target molecule can allow for precise control of the laser’s action. The framework for understanding this principle was outlined by Anderson and Parrish¹¹ in 1983. Fundamentally, a laser causes damage to a target molecule via application of large amounts of energy; however, the laser beam does not discriminate between different molecules in its path. Rather the size and other properties of the molecule play a critical role in determining the amount of energy it is able to absorb before dissipating the excess energy as heat. This excess heat energy is what causes damage to surrounding tissues, or collateral damage. Conceptually, being able to target a molecule without damaging surrounding tissues is our goal as practitioners when using lasers in dermatology. It is accomplished by heating a molecule to just under its thermal relaxation time (ie, the time needed for a molecule to dissipate half of the energy applied), thus allowing for acceptable results with regard to efficacy balanced with side effects.¹²

Conclusion

Lasers are an important treatment modality, and their use in dermatology is becoming widespread for many possible indications; however, lasers are complex mechanical devices that have the potential to cause great harm when used incorrectly. By gaining a thorough understanding of the basic physics of lasers, the different types of lasers that are available, and critical concepts regarding the cutaneous application of lasers, physicians can better understand these devices and approach their use confidently and safely.

Lasers have become a critical part of the dermatologist’s armamentarium for modulating cutaneous biology, both in treating skin disorders and providing tangible cosmetic alterations to the skin. Although advances in technology and convenient user interfaces have made modern lasers relatively straightforward to use, they are in fact quite complex and powerful instruments that are capable of considerable damage if not used correctly. Thus it is necessary to establish a framework for the safe and responsible use of lasers in dermatology; fundamental to this tenet is an understanding of the development and physics of lasers. In this article, the fundamental concepts of lasers as well as their interactions with the skin will be discussed to impart a working knowledge of lasers to allow for better, safer use of these important tools.

Development of Lasers

The term laser is an acronym for “light amplification by the stimulated emission of radiation.” Albert Einstein established the framework for the functioning of lasers in his seminal work, “On the Quantum Theory of Radiation,”¹ in which he described how an electron in an atom in an excited state can return to a lower state by emitting energy in the form of a photon of light. Light comprises a portion of the electromagnetic spectrum, rangingfrom UV (200–400 nm) to visible (400 to about 700 nm) to infrared light (about 700 to >3000 nm). The unique properties of light that affect the function of lasers include reflection (eg, seeing a mirror image of a mountain on the surface of a still lake) and refraction (eg, your hand looking larger under the surface of a pool of water).

Despite early theories on lasers, it was not until the late 1950s that the technology finally started to catch up to the science. Researchers experimenting with microwave fields were able to generate a beam of excited ammonia molecules through a resonant cavity, resulting in a uniform (albeit low power) emission of radiation.² Maiman³ expounded on this development by building the first working prototype of a device that radiated light without the use of a microwave. So how exactly do lasers work?

Basic Physics of Lasers

To understand how lasers work, one must have a rudimentary understanding of quantum mechanics. Bohr⁴ revealed that an atom is comprised of a nucleus that is orbited by electrons at discrete distances (ie, only at specific radii), which have corresponding energy levels that increase as the distance from the nucleus increases. With the application of energy, an electron may be excited to a higher energy level, thus increasing its distance from the nucleus, but will then spontaneously return to the lower energy level. By the law of conservation of energy, the excess energy is released as a photon. Although this small amount of energy would not be of much interest at the single particle level, Einstein and Bose discovered that photons were uniquely “gregarious” with the tendency to join together in a common state, leading to the ability to generate a coherent beam of light by simultaneously exciting multiple atoms and their electrons, whereby the return of one electron to a lower energy state generated a chain reaction among the other excited electrons, subsequently prompting the release of photons with the same characteristics as the initial incident photon and returning to a lower energy state.⁵ This process requires several steps to occur in order. First, absorption of energy has to occur among a population of atoms, thus exciting the electrons to higher energy states. When one of the electrons returns to a lower energy level, spontaneous emission will occur with the release of a photon of light. The photon has a certain probability of colliding with other atoms, thereby causing their electrons to return to a lower energy state and release additional photons of light with the same wavelength and in the same direction as the incident photon in a process that is referred to as stimulated emission.⁶ When this process occurs in a cavity with a large number of atoms, the result may lead to a high-energy beam of photons, which becomes the laser beam.

There are some caveats to consider regarding electron population dynamics as outlined by the Boltzmann principle whereby only a small proportion of molecules are in the first excited state and the vast majority are in the ground state (lowest energy) at any given time, but the details of higher-energy transitions in quantum mechanics are beyond the scope of this article.⁷ Primarily, it is important to understand that the ultimate power of a laser’s output depends largely on the population of electrons that are residing at a higher energy state at any given point in time, and the goal of many types of lasers is to achieve a large number of electrons in a high-energy state as opposed to their usual ground state, a process known as population inversion.⁸

This process leads to the fundamental construction of a laser: a population of atoms in a resonant cavity flanked by reflectors that are exposed to some sort of excitation mechanism (known as the pump) with an output mechanism for the laser beam to exit. In practice, the material used to supply the atoms (known as the gain medium) varies and also determines the wavelength and properties of the laser beam due to differences in the discrete energy states of orbiting electrons. Whatever the gain medium being used, the important properties of a laser resulting from these principles is that the beam is monochromatic (consisting of a single wavelength or a very narrow band), coherent (the light is emitted in the same phase and direction), collimated (a narrow beam diameter with limited divergence), and intense (high power per unit area). Consider the differences between a laser pointer and a flashlight; from across the room, the laser pointer output is a small spot of light on the wall whereas the flashlight has long dispersed to a weak, broad swath of light.

Types of Lasers

Different gain media have been used to create a variety of lasers with different properties. In general, lasers fall into 1 of 4 categories: gas discharge, diode, dye, and solid-state lasers.⁹

Although a gas discharge laser theoretically is the simplest laser, whereby a gas is excited by an electric discharge and the excited particles of gas create the laser beam, there are practical considerations such as excessive heat production, which may necessitate the use of cooling coils or some other method for heat dispersion. The excimer laser is a specific type of gas discharge laser in which a noble gas is mixed with halogen and high-current pulses are used to generate excited dimers, hence the term excimer. The excited dimers consisting of 1 halogen molecule and 1 noble gas molecule are only linked in the excited state, thus allowing for more stability in the excited state and enabling a higher proportion of molecules to be in that state at any given time, which increases population inversion and thus helps to maximize the output energy.

Diode lasers employ the use of diodes, or semiconductors that allow current to flow in one direction but not the other (theoretically with infinite resistance in one direction and no resistance in the other direction), thus creating a downstream method to achieve a high-power laser output; however, despite its theoretical efficiency, the use of diode lasers has been limited due to practical considerations of the divergence and quality of the output.

Dye lasers consist of a liquid solution of organic dye in a solvent that is pumped by an optical source. While gas discharge lasers involve excitation of a gas, there is a clear corollary with dye lasers with liquid taking the place of the gas; however, this modality has certain limitations, including the use of toxic materials that degrade naturally; the need to switch cuvettes when changing gain media, which serve as the lasing medium; and a relatively low-power output. One benefit of the dye laser, as alluded to above, is the operator’s capability to switch out cuvettes containing different dyes, thus using one machine to generate widely varying laser beams.

Solid-state lasers are most often used in dermatology. These devices utilize a conducting medium (eg, garnet, sapphire, ruby) doped with trivalent rare-earth ions or transition metal ions (eg, neodymium, ytterbium, erbium, titanium, chromium). This process is a relatively reliable and flexible methodology for generating stable lasers, thus explaining its widespread use. Additionally, these solid-state lasers are particularly amenable to modifications (eg, Q-switching).

Considerations for Lasers

Quality switching (known as Q-switching) is a method used to generate a shorter burst of a higher-power laser output.¹⁰ The longer the electrons have to become excited within a resonant cavity, the higher the number that may end up in an excited state, thus allowing for a higher ultimate energy output to a certain point. The quality of a medium, in general, refers to the ability of light exiting a medium to return. Within a cavity, the ability of light to go back and forth through the lasing medium is critical in achieving stimulated emission and thus laser beam output; however, in a low-quality medium, population inversion can still occur to allow a greater proportion of electrons to reside in a higher energy state. There are multiple mechanisms to switch the quality of a medium, but the ultimate result always is for the quality to be switched to high so that the light beams can immediately start achieving stimulated emission of a “primed” population of high-energy, population-inverted electrons, resulting in a much higher output power.

Selective thermolysis is critical for understanding modern laser use. To fully comprehend its meaning, one must first understand that the interaction of a laser with the skin depends on a number of factors, including the power density of the laser itself (the beam characteristics), the length of time of exposure, and the physical properties of the targeted molecules. Although there is some modulation of laser function via the wavelength of the laser (eg, higher wavelengths penetrate deeper), the properties of the target molecule can allow for precise control of the laser’s action. The framework for understanding this principle was outlined by Anderson and Parrish¹¹ in 1983. Fundamentally, a laser causes damage to a target molecule via application of large amounts of energy; however, the laser beam does not discriminate between different molecules in its path. Rather the size and other properties of the molecule play a critical role in determining the amount of energy it is able to absorb before dissipating the excess energy as heat. This excess heat energy is what causes damage to surrounding tissues, or collateral damage. Conceptually, being able to target a molecule without damaging surrounding tissues is our goal as practitioners when using lasers in dermatology. It is accomplished by heating a molecule to just under its thermal relaxation time (ie, the time needed for a molecule to dissipate half of the energy applied), thus allowing for acceptable results with regard to efficacy balanced with side effects.¹²

Conclusion

Lasers are an important treatment modality, and their use in dermatology is becoming widespread for many possible indications; however, lasers are complex mechanical devices that have the potential to cause great harm when used incorrectly. By gaining a thorough understanding of the basic physics of lasers, the different types of lasers that are available, and critical concepts regarding the cutaneous application of lasers, physicians can better understand these devices and approach their use confidently and safely.

1. A 71-year-old woman with a pacemaker/defibrillator is undergoing Mohs micrographic surgery. Which method is the safest for hemostasis during surgery?

a. biterminal electrocoagulation
b. electrocautery
c. electrodesiccation
d. monopolar electrocoagulation
e. monoterminal electrocoagulation

2. Which method usually causes the deepest level of tissue damage during hemostasis?

a. electrocautery
b. electrocoagulation
c. electrodesiccation
d. electrofulguration
e. electrosection

3. Which electrosurgical mode has the highest maximum output power?

a. bipolar mode

b. coagulation mode

c. cutting mode

d. fulguration mode

e. monoterminal mode

4. A 59-year-old woman is scheduled for curettage and electrodesiccation of a superficial basal cell carcinoma on the upper back. Which method is preferred for deep electrodesiccation?

a. large-tip electrode and coagulation current
b. large-tip electrode in fulguration mode
c. small-tip electrode and coagulation current
d. small-tip electrode and cutting current
e. small-tip electrode in fulguration mode

5. A 32-year-old Asian woman is scheduled for superficial electrosurgical destruction of a small flat seborrheic keratosis on the face. Which treatment method is preferred?

a. large-tip electrode and coagulation current
b. large-tip electrode and cutting current
c. large-tip electrode and fulguration current in noncontact mode at the maximum power
d. small-tip electrode and cutting current
e. small-tip electrode and fulguration current at the maximum power

1. A 71-year-old woman with a pacemaker/defibrillator is undergoing Mohs micrographic surgery. Which method is the safest for hemostasis during surgery?

a. biterminal electrocoagulation
b. electrocautery
c. electrodesiccation
d. monopolar electrocoagulation
e. monoterminal electrocoagulation

2. Which method usually causes the deepest level of tissue damage during hemostasis?

a. electrocautery
b. electrocoagulation
c. electrodesiccation
d. electrofulguration
e. electrosection

3. Which electrosurgical mode has the highest maximum output power?

a. bipolar mode

b. coagulation mode

c. cutting mode

d. fulguration mode

e. monoterminal mode

4. A 59-year-old woman is scheduled for curettage and electrodesiccation of a superficial basal cell carcinoma on the upper back. Which method is preferred for deep electrodesiccation?

a. large-tip electrode and coagulation current
b. large-tip electrode in fulguration mode
c. small-tip electrode and coagulation current
d. small-tip electrode and cutting current
e. small-tip electrode in fulguration mode

5. A 32-year-old Asian woman is scheduled for superficial electrosurgical destruction of a small flat seborrheic keratosis on the face. Which treatment method is preferred?

a. large-tip electrode and coagulation current
b. large-tip electrode and cutting current
c. large-tip electrode and fulguration current in noncontact mode at the maximum power
d. small-tip electrode and cutting current
e. small-tip electrode and fulguration current at the maximum power

1. A 71-year-old woman with a pacemaker/defibrillator is undergoing Mohs micrographic surgery. Which method is the safest for hemostasis during surgery?

a. biterminal electrocoagulation
b. electrocautery
c. electrodesiccation
d. monopolar electrocoagulation
e. monoterminal electrocoagulation

2. Which method usually causes the deepest level of tissue damage during hemostasis?

a. electrocautery
b. electrocoagulation
c. electrodesiccation
d. electrofulguration
e. electrosection

3. Which electrosurgical mode has the highest maximum output power?

a. bipolar mode

b. coagulation mode

c. cutting mode

d. fulguration mode

e. monoterminal mode

4. A 59-year-old woman is scheduled for curettage and electrodesiccation of a superficial basal cell carcinoma on the upper back. Which method is preferred for deep electrodesiccation?

a. large-tip electrode and coagulation current
b. large-tip electrode in fulguration mode
c. small-tip electrode and coagulation current
d. small-tip electrode and cutting current
e. small-tip electrode in fulguration mode

5. A 32-year-old Asian woman is scheduled for superficial electrosurgical destruction of a small flat seborrheic keratosis on the face. Which treatment method is preferred?

a. large-tip electrode and coagulation current
b. large-tip electrode and cutting current
c. large-tip electrode and fulguration current in noncontact mode at the maximum power
d. small-tip electrode and cutting current
e. small-tip electrode and fulguration current at the maximum power

To improve patient care and outcomes, leading dermatologists offered their recommendations on the top OTC antioxidants. Consideration must be given to:

• Active C
  La Roche-Posay Laboratoire Dermatologique
  “It has 5% vitamin C, which is a known potent antioxidant for skin. It is available in most pharmacies and has a reasonable price point for patients.”—Anthony M. Rossi, MD, New York, New York

•  Super Serum Advance
  iS Clinical
  “Super Serum Advance not only provides antioxidants to the skin, but it also has specifically formulated peptides to increase collagen production. This allows Super Serum Advance to reduce the appearance of fine lines, wrinkles, scar tissue, stretch marks, and uneven pigmentation while providing superior antioxidant protection to the skin.”—Wm. Philip Werschler, Seattle, Washington

•  Urbane Renewal
  Biopelle, Inc
  It has an array of antioxidants but also DNA repair. Plus it goes on very nicely as a serum.”—Joel L. Cohen, Englewood, Colorado

Cutis invites readers to send us their recommendations. Over-the-counter pigment control, facial scrubs, and mineral makeup will be featured in upcoming editions of Cosmetic Corner. Please e-mail your recommendation(s) to cutis@frontlinemedcom.com.

Disclaimer: Opinions expressed herein do not necessarily reflect those of Cutis or Frontline Medical Communications Inc. and shall not be used for product endorsement purposes. Any reference made to a specific commercial product does not indicate or imply that Cutis or Frontline Medical Communications Inc. endorses, recommends, or favors the product mentioned. No guarantee is given to the effects of recommended products.

To improve patient care and outcomes, leading dermatologists offered their recommendations on the top OTC antioxidants. Consideration must be given to:

• Active C
  La Roche-Posay Laboratoire Dermatologique
  “It has 5% vitamin C, which is a known potent antioxidant for skin. It is available in most pharmacies and has a reasonable price point for patients.”—Anthony M. Rossi, MD, New York, New York

•  Super Serum Advance
  iS Clinical
  “Super Serum Advance not only provides antioxidants to the skin, but it also has specifically formulated peptides to increase collagen production. This allows Super Serum Advance to reduce the appearance of fine lines, wrinkles, scar tissue, stretch marks, and uneven pigmentation while providing superior antioxidant protection to the skin.”—Wm. Philip Werschler, Seattle, Washington

•  Urbane Renewal
  Biopelle, Inc
  It has an array of antioxidants but also DNA repair. Plus it goes on very nicely as a serum.”—Joel L. Cohen, Englewood, Colorado

Cutis invites readers to send us their recommendations. Over-the-counter pigment control, facial scrubs, and mineral makeup will be featured in upcoming editions of Cosmetic Corner. Please e-mail your recommendation(s) to cutis@frontlinemedcom.com.

Disclaimer: Opinions expressed herein do not necessarily reflect those of Cutis or Frontline Medical Communications Inc. and shall not be used for product endorsement purposes. Any reference made to a specific commercial product does not indicate or imply that Cutis or Frontline Medical Communications Inc. endorses, recommends, or favors the product mentioned. No guarantee is given to the effects of recommended products.

To improve patient care and outcomes, leading dermatologists offered their recommendations on the top OTC antioxidants. Consideration must be given to:

• Active C
  La Roche-Posay Laboratoire Dermatologique
  “It has 5% vitamin C, which is a known potent antioxidant for skin. It is available in most pharmacies and has a reasonable price point for patients.”—Anthony M. Rossi, MD, New York, New York

•  Super Serum Advance
  iS Clinical
  “Super Serum Advance not only provides antioxidants to the skin, but it also has specifically formulated peptides to increase collagen production. This allows Super Serum Advance to reduce the appearance of fine lines, wrinkles, scar tissue, stretch marks, and uneven pigmentation while providing superior antioxidant protection to the skin.”—Wm. Philip Werschler, Seattle, Washington

•  Urbane Renewal
  Biopelle, Inc
  It has an array of antioxidants but also DNA repair. Plus it goes on very nicely as a serum.”—Joel L. Cohen, Englewood, Colorado

Cutis invites readers to send us their recommendations. Over-the-counter pigment control, facial scrubs, and mineral makeup will be featured in upcoming editions of Cosmetic Corner. Please e-mail your recommendation(s) to cutis@frontlinemedcom.com.

Disclaimer: Opinions expressed herein do not necessarily reflect those of Cutis or Frontline Medical Communications Inc. and shall not be used for product endorsement purposes. Any reference made to a specific commercial product does not indicate or imply that Cutis or Frontline Medical Communications Inc. endorses, recommends, or favors the product mentioned. No guarantee is given to the effects of recommended products.

CHICAGO – Adding epinephrine to a specific formulation of hyaluronic acid already mixed with lidocaine failed to reduce the severity of adverse events following correction of perioral lines in a blinded study.

"Our results using split-face comparison did not reveal a large difference in bruising and pain scores," Dr. Azadeh Shirazi of Scripps Clinic in La Jolla, Calif., reported at the American Academy of Dermatology summer meeting.

Three groups of 10 women with mild to severe lip wrinkles were treated with 1.0 mL of cohesive polydensified matrix hyaluronic acid (CPMHA) alone; CPMHA plus 0.3 mL of lidocaine HCl 1%; or CPMHA plus lidocaine and epinephrine 1:100,000. The volumes in each syringe were adjusted to 1 mL in total.

All injections were performed in the dermis, using serial punctures and linear threading techniques. An entire syringe of one mixture was used on one side, followed by injection of a different mixture on the contralateral side.

Outside evaluators, physician investigators, and patients were blinded to treatment. Bruising was assessed on a 4-point, nonvalidated scale, with 0 being "no visible bruising" and 3 "severe" bruising.

On day 1 post procedure, outside evaluators gave the lowest bruising score to CPMHA alone at about 1.375, followed by CPMHA plus lidocaine and epinephrine at about 1.4, and CPMHA plus lidocaine at about 1.45.

Physicians favored the hyaluronic acid with both pain medications, while patients rated the lidocaine formulation as causing the least bruising.

By day 7, bruising was lower in all groups. The outside evaluators again rated CPMHA alone as causing the least bruising on day 7, while patients and physicians perceived less bruising with the CPMHA-lidocaine formulation. Pain scores followed a similar pattern.

Although not a variable in the study, short-lived edema also was noted in most patients.

It’s possible that there was not enough time for the epinephrine to take full effect as a vasoconstrictor to decrease bruising, Dr. Shirazi said in an interview.

Larger studies are warranted to determine differences between the different formulations, the Dr. Shirazi and her colleagues concluded in the poster.

The study was supported by Merz North America, makers of the CPMHA formulation. Dr. Shirazi has served as an investigator for Allergan, Medicis, and Merz, and as an advisory board member for several pharmaceutical and device companies.

pwendling@frontlinemedcom.com

CHICAGO – Adding epinephrine to a specific formulation of hyaluronic acid already mixed with lidocaine failed to reduce the severity of adverse events following correction of perioral lines in a blinded study.

"Our results using split-face comparison did not reveal a large difference in bruising and pain scores," Dr. Azadeh Shirazi of Scripps Clinic in La Jolla, Calif., reported at the American Academy of Dermatology summer meeting.

Three groups of 10 women with mild to severe lip wrinkles were treated with 1.0 mL of cohesive polydensified matrix hyaluronic acid (CPMHA) alone; CPMHA plus 0.3 mL of lidocaine HCl 1%; or CPMHA plus lidocaine and epinephrine 1:100,000. The volumes in each syringe were adjusted to 1 mL in total.

All injections were performed in the dermis, using serial punctures and linear threading techniques. An entire syringe of one mixture was used on one side, followed by injection of a different mixture on the contralateral side.

Outside evaluators, physician investigators, and patients were blinded to treatment. Bruising was assessed on a 4-point, nonvalidated scale, with 0 being "no visible bruising" and 3 "severe" bruising.

On day 1 post procedure, outside evaluators gave the lowest bruising score to CPMHA alone at about 1.375, followed by CPMHA plus lidocaine and epinephrine at about 1.4, and CPMHA plus lidocaine at about 1.45.

Physicians favored the hyaluronic acid with both pain medications, while patients rated the lidocaine formulation as causing the least bruising.

By day 7, bruising was lower in all groups. The outside evaluators again rated CPMHA alone as causing the least bruising on day 7, while patients and physicians perceived less bruising with the CPMHA-lidocaine formulation. Pain scores followed a similar pattern.

Although not a variable in the study, short-lived edema also was noted in most patients.

It’s possible that there was not enough time for the epinephrine to take full effect as a vasoconstrictor to decrease bruising, Dr. Shirazi said in an interview.

Larger studies are warranted to determine differences between the different formulations, the Dr. Shirazi and her colleagues concluded in the poster.

The study was supported by Merz North America, makers of the CPMHA formulation. Dr. Shirazi has served as an investigator for Allergan, Medicis, and Merz, and as an advisory board member for several pharmaceutical and device companies.

pwendling@frontlinemedcom.com

CHICAGO – Adding epinephrine to a specific formulation of hyaluronic acid already mixed with lidocaine failed to reduce the severity of adverse events following correction of perioral lines in a blinded study.

"Our results using split-face comparison did not reveal a large difference in bruising and pain scores," Dr. Azadeh Shirazi of Scripps Clinic in La Jolla, Calif., reported at the American Academy of Dermatology summer meeting.

Three groups of 10 women with mild to severe lip wrinkles were treated with 1.0 mL of cohesive polydensified matrix hyaluronic acid (CPMHA) alone; CPMHA plus 0.3 mL of lidocaine HCl 1%; or CPMHA plus lidocaine and epinephrine 1:100,000. The volumes in each syringe were adjusted to 1 mL in total.

All injections were performed in the dermis, using serial punctures and linear threading techniques. An entire syringe of one mixture was used on one side, followed by injection of a different mixture on the contralateral side.

Outside evaluators, physician investigators, and patients were blinded to treatment. Bruising was assessed on a 4-point, nonvalidated scale, with 0 being "no visible bruising" and 3 "severe" bruising.

On day 1 post procedure, outside evaluators gave the lowest bruising score to CPMHA alone at about 1.375, followed by CPMHA plus lidocaine and epinephrine at about 1.4, and CPMHA plus lidocaine at about 1.45.

Physicians favored the hyaluronic acid with both pain medications, while patients rated the lidocaine formulation as causing the least bruising.

By day 7, bruising was lower in all groups. The outside evaluators again rated CPMHA alone as causing the least bruising on day 7, while patients and physicians perceived less bruising with the CPMHA-lidocaine formulation. Pain scores followed a similar pattern.

Although not a variable in the study, short-lived edema also was noted in most patients.

It’s possible that there was not enough time for the epinephrine to take full effect as a vasoconstrictor to decrease bruising, Dr. Shirazi said in an interview.

Larger studies are warranted to determine differences between the different formulations, the Dr. Shirazi and her colleagues concluded in the poster.

The study was supported by Merz North America, makers of the CPMHA formulation. Dr. Shirazi has served as an investigator for Allergan, Medicis, and Merz, and as an advisory board member for several pharmaceutical and device companies.

pwendling@frontlinemedcom.com

VANCOUVER, B.C. – Attention to ergonomics may reduce risks for a wide range of musculoskeletal problems and headaches that afflict Mohs surgeons, Dr. Mariusz Sapijaszko said at the annual meeting of the Pacific Dermatologic Association.

The demands of performing Mohs surgery were first detailed in a study of 17 Mohs surgeons at the Mayo Clinic. Nearly two-thirds (59%) had chronic neck pain, half had shoulder pain (53%), and nearly half had lower back pain (41%). About a third experienced eye fatigue and one-fourth had headaches (Dermatol. Surg. 2007;33:1304-13).

Since then, a survey of American College of Mohs Surgery members found that 90% reported some type of musculoskeletal symptoms or injuries (Dermatol. Surg. 2012;38:240-8).

Dr. Sapijaszko of the Western Canada Dermatology Institute, Edmonton, Alberta, offered the following ergonomic tips based on his own clinical practice as well as recommendations offered by researchers who conducted the 2007 Mayo Clinic study and those focused on optimizing the operating theater environment (ANZ J. Surg. 2010;80:917-24).

To reduce neck-related symptoms:

• Keep your gaze angle between 15 and 30 degrees below horizontal.

• Position the patient close to you.

• Take short surgery breaks to stretch and adjust your posture.

• Use a stool with sternal support or a sit/stand stool.

To avoid lower back pain:

• Change positions frequently.

• Use a foot rest or foot rail.

• Use a stool with sternal support.

To prevent eye fatigue:

• Decrease the intensity of surgical lighting with a dimmer switch.

• Use goggles or glasses that contain antiglare film.

• Use brushed steel instead of polished steel instruments.

To minimize peripheral edema:

• Wear compression stockings.

• Use a foot rest or foot rail.

• Use gel insoles, or antifatigue floor mats.

To reduce headaches:

• Keep ambient noise below 56 dB.

• Select music based on the preference of the surgeon, patient, and other OR staff.

To optimize your comfort, optimize patient comfort:

• Select a procedure table that has adjustable positions for knee, hip, and neck angles as well as good lower back and lumbar support and a comfortable pillow type and position.

"You need to lie down on your own table and find out how good or bad it feels," Dr. Sapijaszko advised. He favors fully adjustable tables such as those used in the massage industry, and recommends a 12-degree tilt for the patient’s head.

dbrunk@frontlinemedcom.com

On Twitter @dougbrunk

VANCOUVER, B.C. – Attention to ergonomics may reduce risks for a wide range of musculoskeletal problems and headaches that afflict Mohs surgeons, Dr. Mariusz Sapijaszko said at the annual meeting of the Pacific Dermatologic Association.

The demands of performing Mohs surgery were first detailed in a study of 17 Mohs surgeons at the Mayo Clinic. Nearly two-thirds (59%) had chronic neck pain, half had shoulder pain (53%), and nearly half had lower back pain (41%). About a third experienced eye fatigue and one-fourth had headaches (Dermatol. Surg. 2007;33:1304-13).

Since then, a survey of American College of Mohs Surgery members found that 90% reported some type of musculoskeletal symptoms or injuries (Dermatol. Surg. 2012;38:240-8).

Dr. Sapijaszko of the Western Canada Dermatology Institute, Edmonton, Alberta, offered the following ergonomic tips based on his own clinical practice as well as recommendations offered by researchers who conducted the 2007 Mayo Clinic study and those focused on optimizing the operating theater environment (ANZ J. Surg. 2010;80:917-24).

To reduce neck-related symptoms:

• Keep your gaze angle between 15 and 30 degrees below horizontal.

• Position the patient close to you.

• Take short surgery breaks to stretch and adjust your posture.

• Use a stool with sternal support or a sit/stand stool.

To avoid lower back pain:

• Change positions frequently.

• Use a foot rest or foot rail.

• Use a stool with sternal support.

To prevent eye fatigue:

• Decrease the intensity of surgical lighting with a dimmer switch.

• Use goggles or glasses that contain antiglare film.

• Use brushed steel instead of polished steel instruments.

To minimize peripheral edema:

• Wear compression stockings.

• Use a foot rest or foot rail.

• Use gel insoles, or antifatigue floor mats.

To reduce headaches:

• Keep ambient noise below 56 dB.

• Select music based on the preference of the surgeon, patient, and other OR staff.

To optimize your comfort, optimize patient comfort:

• Select a procedure table that has adjustable positions for knee, hip, and neck angles as well as good lower back and lumbar support and a comfortable pillow type and position.

"You need to lie down on your own table and find out how good or bad it feels," Dr. Sapijaszko advised. He favors fully adjustable tables such as those used in the massage industry, and recommends a 12-degree tilt for the patient’s head.

dbrunk@frontlinemedcom.com

On Twitter @dougbrunk

VANCOUVER, B.C. – Attention to ergonomics may reduce risks for a wide range of musculoskeletal problems and headaches that afflict Mohs surgeons, Dr. Mariusz Sapijaszko said at the annual meeting of the Pacific Dermatologic Association.

The demands of performing Mohs surgery were first detailed in a study of 17 Mohs surgeons at the Mayo Clinic. Nearly two-thirds (59%) had chronic neck pain, half had shoulder pain (53%), and nearly half had lower back pain (41%). About a third experienced eye fatigue and one-fourth had headaches (Dermatol. Surg. 2007;33:1304-13).

Since then, a survey of American College of Mohs Surgery members found that 90% reported some type of musculoskeletal symptoms or injuries (Dermatol. Surg. 2012;38:240-8).

Dr. Sapijaszko of the Western Canada Dermatology Institute, Edmonton, Alberta, offered the following ergonomic tips based on his own clinical practice as well as recommendations offered by researchers who conducted the 2007 Mayo Clinic study and those focused on optimizing the operating theater environment (ANZ J. Surg. 2010;80:917-24).

To reduce neck-related symptoms:

• Keep your gaze angle between 15 and 30 degrees below horizontal.

• Position the patient close to you.

• Take short surgery breaks to stretch and adjust your posture.

• Use a stool with sternal support or a sit/stand stool.

To avoid lower back pain:

• Change positions frequently.

• Use a foot rest or foot rail.

• Use a stool with sternal support.

To prevent eye fatigue:

• Decrease the intensity of surgical lighting with a dimmer switch.

• Use goggles or glasses that contain antiglare film.

• Use brushed steel instead of polished steel instruments.

To minimize peripheral edema:

• Wear compression stockings.

• Use a foot rest or foot rail.

• Use gel insoles, or antifatigue floor mats.

To reduce headaches:

• Keep ambient noise below 56 dB.

• Select music based on the preference of the surgeon, patient, and other OR staff.

To optimize your comfort, optimize patient comfort:

• Select a procedure table that has adjustable positions for knee, hip, and neck angles as well as good lower back and lumbar support and a comfortable pillow type and position.

"You need to lie down on your own table and find out how good or bad it feels," Dr. Sapijaszko advised. He favors fully adjustable tables such as those used in the massage industry, and recommends a 12-degree tilt for the patient’s head.

dbrunk@frontlinemedcom.com

On Twitter @dougbrunk

Dermatologists frequently encounter patients who inquire about the need to buy special clothing and hats that claim to block UV light rather than using their regular clothing and hats. A patient may argue that he/she has never gotten sunburned through his/her favorite T-shirt while fishing, so why does he/she need to buy special clothing? The answer to this question is not straightforward. The dermatologist could easily say yes and advise patients to buy special sun-protective clothing, which could be especially tempting if a practitioner actually sells these items in the office. However, when considering evidence-based medicine, one needs to look at the data to appropriately answer the question.

Although it is still evolving, a standard has been set for UV protection factor (UPF) in the United States as well as other countries.¹ Clothing with the maximum UPF rating of 50 blocks 98% of UVA/UVB radiation. Although there are data published in the literature regarding sun-protective clothing, there are scant data in the clinical dermatologic literature.^2-5 To give patients an educated answer to this question, we measured and compared UVA/UVB radiation transmittance through regular (ie, non–UPF rated) clothing versus sun-protective clothing with a UPF rating.

Materials and Methods

A digital handheld UVA/UVB meter with an absorption spectrum of 280 to 400 nm was used to measure UV energy transmitted through sample clothing articles. The meter measured UVA/UVB light with a maximum reading of 40 mW/cm². Clothing articles were selected of varied material/color and intended use.

Regular clothing articles included a straw golf hat (Figure 1A), an off-white and blue baseball hat (70% wool)(Figure 1B), a black baseball hat (100% wool)(Figure 1C), a white athletic tank shirt (100% cotton), a white T-shirt/undershirt (100% cotton), a thin-weave blue T-shirt (100% cotton), and a conventional-weave blue T-shirt (100% cotton)(Figure 1D). The regular clothing items, with the exception of the hats, had been laundered in conventional (ie, non–UV blocking) laundry detergent and no chemicals were applied to enhance UVA/UVB blocking properties. The exact number of times the items were laundered was unknown.

Figure 1. Regular clothing articles included a straw golf hat (A), an off-white and blue baseball hat (B), a black baseball hat (C), and white and blue T-shirts (D).

Sun-protective clothing articles included a polyester floral splash bucket hat and a polyester ruffled swim romper (Figure 2), both with a UPF rating of 50+. These items were purchased from a manufacturer who regularly promotes sun-protective clothing to both dermatologists and the general public. The company “guarantees” a UPF rating of 50 and advertises that these clothing articles block 98% of harmful UV rays. These items were not laundered prior to the study, and no chemicals were applied to enhance UVA/UVB blocking properties.

Figure 2. Sun-protective clothing articles included a floral splash bucket hat and a ruffled swim romper (UV protection factor 50+).

The UVA/UVB meter was calibrated on a clear cloudless July day in Frankfort, Illinois. An initial reading was taken without any obstruction to the sunlight. The regular and sun-protective clothing articles then were placed over the meter to measure the amount of UVA/UVB transmitted through each item. Measurements were taken for each article of clothing after the meter was covered by the respective material for 10 seconds. Care was taken to cover the meter with only 1 layer of material for each article, which was intended to mimic the degree of UVA/UVB blocking and transmittance during normal wear.

Results

The full results from the study are outlined in the Table. The unobstructed sunlight exposure exceeded the maximum measure of 40 mW/cm², indicating there was a sufficient amount of sunlight to conduct testing.

The data show that both regular and sun-protective clothing blocked UVA/UVB rays in the 280- to 400-nm range. The Table outlines the level of UVA/UVB transmittance for each article of clothing; a lower number indicates less UVA/UVB transmittance occurred and more radiation was blocked.

Several of the regular clothing blocked more UV radiation than the sun-protective clothing; specifically, the data indicate that the baseball hats or the straw golf hat provided better protection than the sun-protective bucket hat. The black baseball hat provided the best UV protection. However, the straw golf hat provided adequate protection and better coverage, making it the best recommendation for patients.

Comment

Several of the regular items included in the study allowed less UVA/UVB transmission than the sun-protective clothing. Although our small study tested a limited number and type of articles, we assert that similar regular clothing would have similar transmittance.

There are various factors that affect UVA/UVB transmittance. Fabric construction, weight, thickness, composition, and color will affect the degree of UVA/UVB transmittance.¹ In our study, the thickness, weave, and color of the fabric of the regular hats may have contributed to the superior results compared with the sun-protective hat. It could be postulated that cotton is inherently a superior fabric to the polyester sun-protective clothing fabric. With regard to the regular T-shirts, thickness, weave, and color also may have played a role in blocking UVA/UVB transmittance.

Patients may be assured of a sufficient amount of UVA/UVB blocking with sun-protective clothing. However, our study indicated that the regular clothing articles we tested provided similar, if not better, protection against UV radiation compared with the sun-protective clothing articles.

Conclusion

Based on the data, we would advise patients that they do not need to buy special sun-protective clothing that claims to block UV radiation, as regular clothing will provide equivalent protection against UVA/UVB radiation. However, these findings do not suggest that the claims for sun-protective clothing are inaccurate. Nevertheless, similar UVA/UVB blocking may be achieved with clothing already owned by patients.

Dermatologists frequently encounter patients who inquire about the need to buy special clothing and hats that claim to block UV light rather than using their regular clothing and hats. A patient may argue that he/she has never gotten sunburned through his/her favorite T-shirt while fishing, so why does he/she need to buy special clothing? The answer to this question is not straightforward. The dermatologist could easily say yes and advise patients to buy special sun-protective clothing, which could be especially tempting if a practitioner actually sells these items in the office. However, when considering evidence-based medicine, one needs to look at the data to appropriately answer the question.

Although it is still evolving, a standard has been set for UV protection factor (UPF) in the United States as well as other countries.¹ Clothing with the maximum UPF rating of 50 blocks 98% of UVA/UVB radiation. Although there are data published in the literature regarding sun-protective clothing, there are scant data in the clinical dermatologic literature.^2-5 To give patients an educated answer to this question, we measured and compared UVA/UVB radiation transmittance through regular (ie, non–UPF rated) clothing versus sun-protective clothing with a UPF rating.

Materials and Methods

A digital handheld UVA/UVB meter with an absorption spectrum of 280 to 400 nm was used to measure UV energy transmitted through sample clothing articles. The meter measured UVA/UVB light with a maximum reading of 40 mW/cm². Clothing articles were selected of varied material/color and intended use.

Regular clothing articles included a straw golf hat (Figure 1A), an off-white and blue baseball hat (70% wool)(Figure 1B), a black baseball hat (100% wool)(Figure 1C), a white athletic tank shirt (100% cotton), a white T-shirt/undershirt (100% cotton), a thin-weave blue T-shirt (100% cotton), and a conventional-weave blue T-shirt (100% cotton)(Figure 1D). The regular clothing items, with the exception of the hats, had been laundered in conventional (ie, non–UV blocking) laundry detergent and no chemicals were applied to enhance UVA/UVB blocking properties. The exact number of times the items were laundered was unknown.

Figure 1. Regular clothing articles included a straw golf hat (A), an off-white and blue baseball hat (B), a black baseball hat (C), and white and blue T-shirts (D).

Sun-protective clothing articles included a polyester floral splash bucket hat and a polyester ruffled swim romper (Figure 2), both with a UPF rating of 50+. These items were purchased from a manufacturer who regularly promotes sun-protective clothing to both dermatologists and the general public. The company “guarantees” a UPF rating of 50 and advertises that these clothing articles block 98% of harmful UV rays. These items were not laundered prior to the study, and no chemicals were applied to enhance UVA/UVB blocking properties.

Figure 2. Sun-protective clothing articles included a floral splash bucket hat and a ruffled swim romper (UV protection factor 50+).

The UVA/UVB meter was calibrated on a clear cloudless July day in Frankfort, Illinois. An initial reading was taken without any obstruction to the sunlight. The regular and sun-protective clothing articles then were placed over the meter to measure the amount of UVA/UVB transmitted through each item. Measurements were taken for each article of clothing after the meter was covered by the respective material for 10 seconds. Care was taken to cover the meter with only 1 layer of material for each article, which was intended to mimic the degree of UVA/UVB blocking and transmittance during normal wear.

Results

The full results from the study are outlined in the Table. The unobstructed sunlight exposure exceeded the maximum measure of 40 mW/cm², indicating there was a sufficient amount of sunlight to conduct testing.

The data show that both regular and sun-protective clothing blocked UVA/UVB rays in the 280- to 400-nm range. The Table outlines the level of UVA/UVB transmittance for each article of clothing; a lower number indicates less UVA/UVB transmittance occurred and more radiation was blocked.

Several of the regular clothing blocked more UV radiation than the sun-protective clothing; specifically, the data indicate that the baseball hats or the straw golf hat provided better protection than the sun-protective bucket hat. The black baseball hat provided the best UV protection. However, the straw golf hat provided adequate protection and better coverage, making it the best recommendation for patients.

Comment

Several of the regular items included in the study allowed less UVA/UVB transmission than the sun-protective clothing. Although our small study tested a limited number and type of articles, we assert that similar regular clothing would have similar transmittance.

There are various factors that affect UVA/UVB transmittance. Fabric construction, weight, thickness, composition, and color will affect the degree of UVA/UVB transmittance.¹ In our study, the thickness, weave, and color of the fabric of the regular hats may have contributed to the superior results compared with the sun-protective hat. It could be postulated that cotton is inherently a superior fabric to the polyester sun-protective clothing fabric. With regard to the regular T-shirts, thickness, weave, and color also may have played a role in blocking UVA/UVB transmittance.

Patients may be assured of a sufficient amount of UVA/UVB blocking with sun-protective clothing. However, our study indicated that the regular clothing articles we tested provided similar, if not better, protection against UV radiation compared with the sun-protective clothing articles.

Conclusion

Based on the data, we would advise patients that they do not need to buy special sun-protective clothing that claims to block UV radiation, as regular clothing will provide equivalent protection against UVA/UVB radiation. However, these findings do not suggest that the claims for sun-protective clothing are inaccurate. Nevertheless, similar UVA/UVB blocking may be achieved with clothing already owned by patients.

Dermatologists frequently encounter patients who inquire about the need to buy special clothing and hats that claim to block UV light rather than using their regular clothing and hats. A patient may argue that he/she has never gotten sunburned through his/her favorite T-shirt while fishing, so why does he/she need to buy special clothing? The answer to this question is not straightforward. The dermatologist could easily say yes and advise patients to buy special sun-protective clothing, which could be especially tempting if a practitioner actually sells these items in the office. However, when considering evidence-based medicine, one needs to look at the data to appropriately answer the question.

Although it is still evolving, a standard has been set for UV protection factor (UPF) in the United States as well as other countries.¹ Clothing with the maximum UPF rating of 50 blocks 98% of UVA/UVB radiation. Although there are data published in the literature regarding sun-protective clothing, there are scant data in the clinical dermatologic literature.^2-5 To give patients an educated answer to this question, we measured and compared UVA/UVB radiation transmittance through regular (ie, non–UPF rated) clothing versus sun-protective clothing with a UPF rating.

Materials and Methods

A digital handheld UVA/UVB meter with an absorption spectrum of 280 to 400 nm was used to measure UV energy transmitted through sample clothing articles. The meter measured UVA/UVB light with a maximum reading of 40 mW/cm². Clothing articles were selected of varied material/color and intended use.

Regular clothing articles included a straw golf hat (Figure 1A), an off-white and blue baseball hat (70% wool)(Figure 1B), a black baseball hat (100% wool)(Figure 1C), a white athletic tank shirt (100% cotton), a white T-shirt/undershirt (100% cotton), a thin-weave blue T-shirt (100% cotton), and a conventional-weave blue T-shirt (100% cotton)(Figure 1D). The regular clothing items, with the exception of the hats, had been laundered in conventional (ie, non–UV blocking) laundry detergent and no chemicals were applied to enhance UVA/UVB blocking properties. The exact number of times the items were laundered was unknown.

Figure 1. Regular clothing articles included a straw golf hat (A), an off-white and blue baseball hat (B), a black baseball hat (C), and white and blue T-shirts (D).

Sun-protective clothing articles included a polyester floral splash bucket hat and a polyester ruffled swim romper (Figure 2), both with a UPF rating of 50+. These items were purchased from a manufacturer who regularly promotes sun-protective clothing to both dermatologists and the general public. The company “guarantees” a UPF rating of 50 and advertises that these clothing articles block 98% of harmful UV rays. These items were not laundered prior to the study, and no chemicals were applied to enhance UVA/UVB blocking properties.

Figure 2. Sun-protective clothing articles included a floral splash bucket hat and a ruffled swim romper (UV protection factor 50+).

The UVA/UVB meter was calibrated on a clear cloudless July day in Frankfort, Illinois. An initial reading was taken without any obstruction to the sunlight. The regular and sun-protective clothing articles then were placed over the meter to measure the amount of UVA/UVB transmitted through each item. Measurements were taken for each article of clothing after the meter was covered by the respective material for 10 seconds. Care was taken to cover the meter with only 1 layer of material for each article, which was intended to mimic the degree of UVA/UVB blocking and transmittance during normal wear.

Results

The full results from the study are outlined in the Table. The unobstructed sunlight exposure exceeded the maximum measure of 40 mW/cm², indicating there was a sufficient amount of sunlight to conduct testing.

The data show that both regular and sun-protective clothing blocked UVA/UVB rays in the 280- to 400-nm range. The Table outlines the level of UVA/UVB transmittance for each article of clothing; a lower number indicates less UVA/UVB transmittance occurred and more radiation was blocked.

Several of the regular clothing blocked more UV radiation than the sun-protective clothing; specifically, the data indicate that the baseball hats or the straw golf hat provided better protection than the sun-protective bucket hat. The black baseball hat provided the best UV protection. However, the straw golf hat provided adequate protection and better coverage, making it the best recommendation for patients.

Comment

Several of the regular items included in the study allowed less UVA/UVB transmission than the sun-protective clothing. Although our small study tested a limited number and type of articles, we assert that similar regular clothing would have similar transmittance.

There are various factors that affect UVA/UVB transmittance. Fabric construction, weight, thickness, composition, and color will affect the degree of UVA/UVB transmittance.¹ In our study, the thickness, weave, and color of the fabric of the regular hats may have contributed to the superior results compared with the sun-protective hat. It could be postulated that cotton is inherently a superior fabric to the polyester sun-protective clothing fabric. With regard to the regular T-shirts, thickness, weave, and color also may have played a role in blocking UVA/UVB transmittance.

Patients may be assured of a sufficient amount of UVA/UVB blocking with sun-protective clothing. However, our study indicated that the regular clothing articles we tested provided similar, if not better, protection against UV radiation compared with the sun-protective clothing articles.

Conclusion

Based on the data, we would advise patients that they do not need to buy special sun-protective clothing that claims to block UV radiation, as regular clothing will provide equivalent protection against UVA/UVB radiation. However, these findings do not suggest that the claims for sun-protective clothing are inaccurate. Nevertheless, similar UVA/UVB blocking may be achieved with clothing already owned by patients.