Drug-Induced Oral Erythema Multiforme: A Report of a Rare Case

Erythema multiforme (EM) is an acute-onset, self-limiting inflammatory condition affecting the skin and mucous membranes. It exhibits a range of skin lesions, which is why it is referred to as "multiforme." Oral lesions, usually inflammatory and frequently marked by rapidly rupturing vesicles and bullae, often constitute a significant clinical feature. The exact etiology is obscure; however, it may be caused by multiple triggering factors. The most well-established connection is with a previous herpes simplex virus infection, while a smaller percentage of cases (<10%) are linked to drug use. Based on mucosal involvement, the condition is classified into two types: EM minor and EM major. Stevens-Johnson syndrome and toxic epidermal necrolysis (Lyell's disease) are now recognized as separate clinical conditions. EM usually exhibits a self-limiting course, with lesions typically improving within a few weeks. Avoiding triggers and using steroid therapy can be effective treatments. This paper documents a rare case of drug-induced oral EM featuring characteristic lip and intraoral lesions. The patient developed painful oral ulcers and difficulty in swallowing after taking azithromycin for a sore throat and fever. Clinical examination revealed multiple, hemorrhagic encrustations on the lips, along with ulcers on the right buccal mucosa and vesicular eruptions on the palate. The acute onset of multiple oral ulcers associated with a recent drug intake led to a diagnosis of drug-induced oral EM. Treatment included systemic prednisolone, topical triamcinolone paste, and supportive oral care. No recurrence was observed during the six-month follow-up.