Over the last decade, the use of mobile phones has changed drastically with the advent of more technologically advanced smartphones.1 Mobile phones are no longer used primarily as devices for talking but rather for text messaging, reading the news, drafting emails, browsing websites, and connecting with others on social media. Considering the increased utility and popularity of social media along with the greater reliance on smartphones, individuals in the United States and worldwide are undoubtedly spending more time on their handheld devices.2 With the increase in use and overuse of smartphones, many aspects of society and health are likely affected. Many celebrities who frequently post on social media platforms also have alluded to or directly discussed changes in their dermatologic health secondary to their increased use of smartphones.3 Numerous studies have investigated the positive and negative effects of smartphone use on various musculoskeletal conditions of the upper extremities4,5 and the social effects of smartphone use on behavior and child development.6,7 Lee et al8 studied the effects of smartphone use on upper extremity muscle pain and activity in relation to 1- or 2-handed operation. In this study, Lee et al8 measured the muscle activity and tenderness in 10 women aged 20 to 22 years after a series of timed periods of smartphone use. They concluded that smartphone use resulted in greater muscle activity and tenderness, especially in 1-handed use compared to 2-handed use.8 Inal et al9 investigated smartphone overuse effects on hand strength and function in 102 college students and discovered that smartphone overuse was correlated with decreased pinch strength, increased median nerve cross-sectional area, and pain in the first digits.9
However, few articles have been published investigating skin changes to the digits in relation to smartphone use (Figure 1). In a PubMed search of articles indexed for MEDLINE using the terms smartphone, phone, cell phone, electronic device, handheld device, fifth digit, or skin changes, the authors were unable to find any studies in the literature that involved smartphone use and skin changes to the digits. Based on informal clinical observation and personal experiences, we hypothesized that changes to the fifth digit, likely due to holding a smartphone, would be prevalent and would correlate with amount of time spent on smartphones per day (Figure 2). We also were interested in investigating any other potential correlations with changes to the fifth digit, such as type of smartphone used.
The study used a cross-sectional design. From September 2018 to December 2018, 374 individuals 18 years or older were recruited to complete a 5-minute anonymous survey online. Using email referrals and social media, participants were presented with a link to a Google survey that only allowed 1 submission per account. On the first page of the survey, participants were presented with a letter explaining that completion of the survey was entirely voluntary, participants were free to withdraw from the study at any time, and participants were providing consent in completing the survey. The protocol was determined to be exempt by the institutional review board at Nova Southeastern University (Fort Lauderdale, Florida) in September 2018.