Challenges in Diagnosing Lamotrigine-induced DRESS: A Unique Case of Acalculous Cholecystitis in Epilepsy

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is an infrequent yet severe idiosyncratic reaction to drugs, characterized by a diverse range of systemic manifestations and a mortality rate of 10% to 20%. Commonly associated with anticonvulsant drugs and sulfonamides, DRESS syndrome poses diagnostic challenges due to its variable presentation. This study presents a unique case of lamotrigine-induced DRESS associated with acalculous cholecystitis, an unprecedented manifestation. The patient, initially treated with levetiracetam and lamotrigine for generalized epilepsy, experienced a delayed onset of symptoms, with a European registry of severe cutaneous adverse reactions (RegiSCAR score of 7, confirming the diagnosis. Reactivation of Epstein-Barr virus was detected, suggesting a potential link between herpesvirus reactivation and DRESS pathogenesis. The case underscores the importance of careful monitoring and consideration of atypical organ involvement in DRESS diagnosis. Lamotrigine withdrawal resulted in rapid clinical resolution, allowing for a cautious transition to an alternative anti-epileptic medication which is valproate. This case contributes to the evolving understanding of DRESS syndrome, emphasizing the need for a comprehensive diagnostic approach in complex medication regimens.