Presence of the HLA-A3101 allele in a familial case of drug reaction with eosinophilia and systemic symptoms, secondary to carbamazepine

Anticonvulsants such as carbamazepine and phenytoin are associated with adverse skin reactions ranging from maculopapular exanthems to more severe reactions, including drug reaction with eosinophilia and systemic symptoms (DRESS), Stevens-Johnson syndrome and toxic epidermal necrolysis. In addition to their antiepileptic role, anticonvulsants are also used to treat pain syndromes including trigeminal neuralgia. Until recently, the associated skin reactions were thought to be unpredictable; however, the current literature suggests a genetic predisposition involving the human leucocyte antigen (HLA) in cutaneous reactions associated with carbamazepine usage. We present two familial cases of DRESS secondary to carbamazepine, in which an underlying genetic predisposition and allelic association were identified.