Drug-Induced Pemphigus Vulgaris Following Ceftriaxone Use.

Pemphigus vulgaris (PV) is a rare, potentially life-threatening autoimmune blistering disorder characterized by intraepidermal acantholysis caused by IgG autoantibodies directed against desmoglein 1 and 3. Although most cases are idiopathic, certain medications, including antibiotics, have been implicated as potential triggers in susceptible individuals. We report the case of a 61-year-old man with a history of nonischemic cardiomyopathy, chronic kidney disease, and substance use disorder who developed widespread flaccid bullae six days after initiation of intravenous ceftriaxone for a suspected urinary tract infection. Histopathologic examination demonstrated suprabasal intraepidermal acantholysis with intraepidermal vesicles containing neutrophils and eosinophils, along with preservation of the basal epidermal layer in a characteristic "row of tombstones" pattern, findings highly suggestive of PV. Ceftriaxone was promptly discontinued, and the patient was treated with high-dose systemic corticosteroids, resulting in marked clinical improvement. Ceftriaxone-induced PV is an exceedingly rare adverse reaction, with few cases reported in the literature. The proposed pathogenesis involves drug-induced neoantigen formation or stimulation of pathogenic autoantibody production in genetically predisposed individuals. Early recognition of drug-induced PV is essential, as continued exposure may result in extensive mucocutaneous involvement, secondary infection, and increased morbidity. Prompt withdrawal of the offending agent and initiation of immunosuppressive therapy are critical for improving clinical outcomes.