DRESS syndrome secondary to phenytoin: a case report and review of the literature.

Introduction and importance: Drug reaction with eosinophilia and systemic symptoms (DRESS) is a rare but potentially life-threatening skin reaction to certain drugs in susceptible individuals. This is one of the first reported cases of phenytoin-induced DRESS syndrome in Nepal. The long latency period of 6 months since the starting of Phenytoin therapy and the appearance of symptoms of DRESS makes this case unique and thus adds to the existing literature on DRESS. Case presentation: A 20-year-old woman with a seizure disorder on phenytoin therapy for 6 months presented with a 2-week history of a pruritic, morbilliform rash involving her limbs, neck, chest, and trunk. Examination revealed bilateral palpable, tender lymphadenopathy over axilla and in left inguinal region. Laboratory investigations demonstrated eosinophilia, elevated leukocyte count, elevated C-reactive protein, and altered liver enzymes. Based on the RegiSCAR criteria, the patient was diagnosed with probable phenytoin-induced DRESS. Initial treatment with oral prednisolone and levocetirizine provided partial relief. Later, Phenytoin was discontinued and replaced with levetiracetam resulting in progressive improvement. The rash and pruritus gradually improved, and corticosteroids were tapered over 2 months. Clinical discussion: DRESS presents with fever, rash, eosinophilia, and systemic involvement. Early diagnosis and withdrawal of the offending drug are crucial for managing DRESS. This case underscores the effectiveness of corticosteroids and supportive therapy, highlighting the need for vigilance in patients on anticonvulsants. Conclusion: DRESS syndrome should be suspected in patients on antiepileptics presenting with rash, eosinophilia, and systemic involvement. Timely drug withdrawal and corticosteroid therapy are essential for optimal outcomes.