Lamotrigine-induced severe cutaneous adverse reaction in a patient with N-methyl-D-aspartate receptor autoimmune encephalitis

Abstract

Current case report is regarding a 20-year-old female patient presenting with N-methyl-D-aspartate (NMDA) receptor antibody-positive autoimmune encephalitis and new-onset seizures who developed rapidly progressive erythematous pruritic rash after administration of tablet lamotrigine followed by escalation of its dose and which was combined with tablet sodium valproate and tablet lacosamide. Cutaneous involvement was diffuse but mucosal surfaces were spared. Laboratory investigations revealed mild transaminitis and monocytosis without systemic involvement. A probable lamotrigine‑induced severe cutaneous adverse drug reaction was diagnosed based on temporal association and Naranjo causality assessment.  Prompt discontinuation of lamotrigine and initiation of systemic corticosteroids resulted in complete clinical resolution. Present case highlights risk of occurance of severe cutaneous adverse drug reactions caused by oral lamotrigine when co-administered with sodium valproate which is known to cause enzyme inhibition as well as in the presence of immune dysregulation. There is a need to take precautions where these conditions exist. Early recognition and timely withdrawal of the offending drug are critical to prevent progression to Steven Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN).