Mycoplasma pneumoniae-Induced Erythema Multiforme in an 11-Year-Old Boy: Diagnostic and Therapeutic Challenges

Mycoplasma pneumoniae is a causative agent of respiratory tract infections that can also trigger immune-mediated complications such as erythema multiforme (EM), presenting with characteristic target-like skin lesions. Recognizing M. pneumoniae as a potential cause of EM is crucial for accurate diagnosis and timely intervention. We present the case of an 11-year-old boy hospitalized with M. pneumoniae infection followed by severe EM. Initially presenting with high fever, oral ulcers, and a characteristic rash on his extremities, he was misdiagnosed with pharyngotonsillitis and herpetic gingivostomatitis. His symptoms persisted despite treatment until a positive polymerase chain reaction (PCR) confirmed an M. pneumoniae infection. By day 6, the rash had evolved into target lesions, leading to a revised diagnosis of EM. The patient was treated with IV azithromycin, corticosteroids, and IV immunoglobulin (IVIg), which resulted in significant clinical improvement. Recognizing M. pneumoniae as a potential cause of EM is essential for accurate and prompt diagnosis. Timely identification and a multidisciplinary treatment approach, including appropriate antimicrobial therapy and supportive care, can significantly enhance patient outcomes.