Drug rash with eosinophilia and systemic symptoms (DRESS syndrome), also known as drug-induced hypersensitivity syndrome, is an uncommon severe systemic hypersensitivity drug reaction. It is estimated to occur in 1 in every 1000 to 10,000 drug exposures.1 It can affect patients of all ages and typically presents 2 to 6 weeks after exposure to a culprit medication. Classically, DRESS syndrome presents with often widespread rash, facial edema, systemic symptoms such as fever, lymphadenopathy, and evidence of visceral organ involvement. Peripheral blood eosinophilia is frequently but not universally observed.1,2
Even with proper management, reported DRESS syndrome mortality rates worldwide are approximately 10%2 or higher depending on the degree and type of other organ involvement (eg, cardiac).3 Beyond the acute manifestations of DRESS syndrome, this condition is unique in that some patients develop late-onset sequelae such as myocarditis or autoimmune conditions even years after the initial cutaneous eruption.4 Therefore, longitudinal evaluation is a key component of management.
The clinical myths and pearls presented here highlight some of the commonly held assumptions regarding DRESS syndrome in an effort to illuminate subtleties of managing patients with this condition (Table).
Myth: DRESS syndrome may only be diagnosed when the clinical criteria satisfy one of the established scoring systems.
Patients with DRESS syndrome can have heterogeneous manifestations. As a result, patients may develop a drug hypersensitivity with biological behavior and a natural history compatible with DRESS syndrome that does not fulfill published diagnostic criteria.5 The syndrome also may reveal its component manifestations gradually, thus delaying the diagnosis. The terms mini-DRESS and skirt syndrome have been employed to describe drug eruptions that clearly have systemic symptoms and more complex and pernicious biologic behavior than a simple drug exanthema but do not meet DRESS syndrome criteria. Ultimately, it is important to note that in clinical practice, DRESS syndrome exists on a spectrum of severity and the diagnosis remains a clinical one.
Pearl: The most commonly involved organ in DRESS syndrome is the liver.
Liver involvement is the most common visceral organ involved in DRESS syndrome and is estimated to occur in approximately 45.0% to 86.1% of cases.6,7 If a patient develops the characteristic rash, peripheral blood eosinophilia, and evidence of liver injury, DRESS syndrome must be included in the differential diagnosis.
Hepatitis presenting in DRESS syndrome can be hepatocellular, cholestatic, or mixed.6,7 Case series are varied in whether the transaminitis of DRESS syndrome tends to be more hepatocellular8 or cholestatic.7 Liver dysfunction in DRESS syndrome often lasts longer than in other severe cutaneous adverse drug reactions, and patients may improve anywhere from a few days in milder cases to months to achieve resolution of abnormalities.6,7 Severe hepatic involvement is thought to be the most notable cause of mortality.9