Reactive Infectious Mucocutaneous Eruption Following a Respiratory Infection in an Adolescent: A Case Report

Reactive infectious mucocutaneous eruption (RIME) is a recently defined mucocutaneous manifestation associated with respiratory infections, most commonly reported secondary to Mycoplasma pneumoniae. The core diagnostic criteria of RIME involve greater than or equal to two mucosal areas with erosive mucositis, minimal cutaneous lesions, a recent infectious prodrome, and exclusion of drug-induced etiologies. RIME presents with acute mucositis involving the oral, ocular, and genital mucosa, with presentations similar to other mucocutaneous disorders such as Stevens-Johnson syndrome (SJS), erythema multiforme (EM), and multisystem inflammatory syndrome in children (MIS-C) secondary to SARS-CoV-2 infection. This case report describes a unique presentation of RIME secondary to a Mycoplasma infection, highlighting diagnostic challenges and therapeutic approaches. A 16-year-old male, previously healthy with no significant past medical history, was accepted for transfer to our hospital for evaluation of persistent fever, worsening left lower lobe pneumonia, oral mucositis, and conjunctivitis. On examination, extensive erythema and inflammation throughout the oral cavity, exudative pharyngitis, clear ocular discharge with conjunctival injection, and sloughing of the scrotal skin were noted. The patient's medical history and clinical examination raised initial suspicion of Kawasaki disease or possible MIS-C. Lab studies showed elevated CRP, ESR, and B-type natriuretic peptide (BNP), indicating extensive systemic inflammation; however, the PCR was negative for respiratory syncytial virus (RSV), influenza A and B, and SARS-CoV-2. Further investigations revealed a positive Group A Streptococcus PCR on throat swab, felt to be colonization, and elevated Mycoplasma pneumoniae IgG titers suggested previous or recent exposure; however, acute infection could not be confirmed due to negative PCR and IgM. The patient improved over the following several days after initiation of azithromycin, continuation of clindamycin, and wound care for scrotal and oral mucosal lesions. Differentiating RIME from other mucocutaneous disorders is vital to prescribing proper treatment and preventing further systemic effects. This case underscores the importance of considering Mycoplasma as a potential etiology in patients presenting with mucocutaneous lesions and conjunctivitis following a previous respiratory infection.