A Rare Case of Stevens-Johnson Syndrome in a Young Patient Presenting With Odynophagia Following Antibiotic Use.

BACKGROUND Stevens-Johnson syndrome (SJS) is a rare, immune-mediated mucocutaneous disorder usually triggered by medications or infections. It typically manifests with widespread epidermal detachment and mucosal ulcerations, but atypical cases can present with isolated mucosal involvement, leading to diagnostic uncertainty and delayed treatment. Recognizing such varying presentations is crucial to precent progression to more severe disease and improve outcomes. CASE REPORT We present the case of an 18-year-old male with no significant medical history who presented with severe odynophagia, oral ulcerations, conjunctivitis, and dysuria shortly after completing a course of cefdinir for an upper respiratory infection. Notably, he lacked the characteristic diffuse rash seen in classic SJS. Laboratory evaluation revealed elevated inflammatory markers, and imaging demonstrated non-specific soft tissue edema. Initial management included cessation of cefdinir, intravenous fluids, corticosteroids, and broad supportive care. During hospitalization, he developed macular lesions on the palms and soles and progressive mucosal sloughing. Serologic testing later confirmed elevated Mycoplasma pneumoniae IgM and IgG titers, leading to reclassification of this condition to Mycoplasma pneumoniae-associated SJS (MP-SJS). He was treated with intravenous immunoglobin and azithromycin, with gradual improvement and full recovery after a 2-week hospital course. CONCLUSIONS This case highlights an atypical, mucosal-predominant presentation of Mycoplasma pneumoniae-associated SJS in an adolescent male, initially mimicking severe oropharyngeal infection. Clinicians should maintain a high index of suspicion for SJS in patients presenting with acute mucositis and odynophagia following recent medication use or respiratory illness, even when the cutaneous findings are absent. Early identification, withdrawal of the offending agent, and prompt multidisciplinary care are critical to favorable outcomes.