Approach to Severe Cutaneous Adverse Drug Reactions

Severe cutaneous adverse drug reactions (SCARs) can occur at any age and can be life threatening, although some drugs have been more frequently reported than others. The spectrum of SCARs includes acute generalized exanthematous pustulosis (AGEP), drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome, also known as drug-induced hypersensitivity syndrome (DiHS) or hypersensitivity syndrome (HSS), Stevens-Johnson syndrome (SJS), and toxic epidermal necrolysis (TEN). Immediate withdrawal of the offending drug is the mainstay treatment in SCARs, and rechallenge often leads to recurrent reactions. Cross reactivity and multiple sensitivities have also been reported. The identification of the offending medication at the onset of the disease is therefore essential to avoid future exposures to the same or chemically related compounds. Various algorithms can be useful to identify the culprit drug in the acute stage. Delayed onset from the initiation of treatment differs in the various clinical entities. Therefore, a prompt, accurate diagnosis is crucial for proper identification of the offending agent. After resolution of the disease, cutaneous tests and in vitro tests can be useful for confirmation of drug causality and investigation of possible cross-reactivity. SCARs are rare diseases, given the incidence is extremely low. Multidisciplinary and international teams are required to study these diseases. Further research is needed to fully understand etiopathogenesis and for the development of specific treatments.