Smruti Payal MOHAPATRA, Silpiranjan MISHRA, Atul Anand BAJORIA, Jitendra SHARAN
Cumhuriyet Dental Journal - 2026;29(1):180-183
Erythema multiforme (EM) is an acute immune-mediated mucocutaneous disorder most commonly triggered by infections, particularly herpes simplex virus, or less frequently by medications. Diagnostic differentiation becomes challenging in patients receiving long-term immunosuppressive therapy. This report describes a 56-year-old female on chronic methotrexate therapy for rheumatoid arthritis and fibromyalgia who presented with sudden-onset, painful oral ulcerations without cutaneous involvement or prodromal viral symptoms. Clinical examination revealed ulcerative lesions involving the buccal mucosa and tongue. Drug-induced EM (DIEM) was considered as a differential diagnosis; however, the lesions demonstrated progressive resolution following antiviral therapy with acyclovir and topical corticosteroids, despite continued methotrexate use. Laboratory investigations showed elevated erythrocyte sedimentation rate (ESR) and neutrophilia, indicating an active inflammatory process. The favourable clinical course, absence of lesion progression with ongoing methotrexate therapy, and response to antiviral treatment supported a probable diagnosis of herpes simplex virus-associated erythema multiforme (HAEM). This case highlights the importance of careful clinical assessment, consideration of confounding medications, and cautious interpretation of therapeutic response to avoid unnecessary discontinuation of essential immunosuppressive therapy.
