A 62-year-old female patient with a history of type 1 diabetes mellitus, obesity, and hypertension developed fixed drug eruption following semaglutide administration, representing the first reported case of this reaction to the glucagon-like peptide-1 receptor agonist, according to researchers at Temple University Lewis Katz School of Medicine.

The patient developed characteristic lesions within 72 hours of initiating 2 mg of subcutaneous semaglutide injections weekly. According to the case report, published in JAAD Case Reports, the researchers described the lesions as: "initially erythematous and pruritic reactions [that] subsequently progressed into asymptomatic chronic hyperpigmented patches with an erythematous border."

Physical examination revealed "multiple dusky hyperpigmented round patches with erythematous borders on her buttock and abdomen." A 4-mm punch biopsy from the right buttock demonstrated "lichenoid interface dermatitis ... [with] numerous necrotic keratinocytes ... throughout the epidermis with conspicuous pigment incontinence seen throughout the superficial dermis."

The case highlighted a distinct presentation from previously documented semaglutide reactions. The researchers noted that while drug-induced hypersensitivity reactions, including generalized pruritus and rash, have been documented, this presentation represented a delayed hypersensitivity reaction "characterized by well-defined, recurrent patches at discrete sites, driven by localized immune responses involving drug-specific cytotoxic T cells retained in the skin."

Following discontinuation of semaglutide, the patient showed complete resolution of active lesions at 1-month follow-up, with residual postinflammatory hyperpigmentation.

The researchers concluded: "maintaining a high index of suspicion and advising patients to report any unusual dermatologic reactions during treatment" with glucagon-like peptide-1 receptor agonists.

Full disclosures can be found in the case report.