Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN)

Severe Cutaneous Adverse Reactions (SCARs) are rare but potentially life threatening dermatologic conditions that can result from the use of a variety of different medications. SCARs refer to different hypersensitivity syndromes like Stevens-Johnson Syndrome (SJS), Toxic Epidermal Necrolysis (TEN), and Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS). Although uncommon, these conditions are associated with high morbidity and mortality rates, especially in immunocompromised populations. Thus, early recognition and immediate intervention are salient.

SJS and TEN are a disease continuum that are differentiated by the extent of epidermal detachment. SJS involves less than 10% of body surface area while TEN involves more than 30% of BSA. Anything in between would be considered overlap and would involve both conditions. These reactions present with flu like symptoms, followed by rapidly progressing, painful erythematous macules, bullae, and mucosal involvement. The mortality rate of TEN can exceed 30%, especially in elderly patients or those with underlying systemic illness.

DRESS syndrome is another hypersensitivity reaction. This is characterized by widespread rash, eosinophilia, lymphadenopathy, fever, and potentially the involvement of internal organs. Onset of symptoms begin between 2 to 8 weeks after drug initiation, which presents a challenge in the identification of the cause. Treatment would include immediate discontinuation of the offending agent and initiation of supportive care. This may include the use of corticosteroids.

Some medications that may lead to SCARs include anticonvulsants, antibiotics, allopurinol, NSAIDs, and antipsychotics. An additional risk factor would include the genetic predisposition of the HLAB1502 gene, prominent in Asian populations. Pharmacists, thus, play a critical role in identifying high risk medications and providing proper counseling on these medications. Discussing what symptoms look like, the potential delay in onset of these reactions, and prompt discontinuation of the agents are all salient when counseling a patient.

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Kardaun SH, Sekula P, Valeyrie-Allanore L, et al. Drug reaction with eosinophilia and systemic symptoms (DRESS): an original multisystem adverse drug reaction. Br J Dermatol. 2013;169(5):1071-1080. doi:10.1111/bjd.12501

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