Reactive Infectious Mucocutaneous Eruption (RIME) Associated with Mycoplasma pneumoniae: Clinical and Immunological Insights from Pediatric Cases

Reactive infectious mucocutaneous eruption (RIME) is a rare pediatric condition characterized by severe mucositis, minimal cutaneous involvement, and an infectious rather than drug-induced etiology. <i>Mycoplasma pneumoniae</i> (<i>M. Pneumoniae</i>) represents the most frequently identified trigger, although an increasing number of alternative pathogens have been reported. Its clinical overlap with Stevens-Johnson syndrome (SJS) makes early recognition difficult. We reviewed literature data on the topic and described our center's experience with three pediatric cases of <i>M. pneumoniae</i>-associated RIME. Medical records, laboratory results, and imaging were systematically analyzed. All patients were male, aged 2 to 12 years and originated from rural communities. Etiologic confirmation was achieved via <i>M. pneumoniae</i> IgM serology and/or polymerase chain reaction. Clinical exam modifications included multi-site mucositis (oral, ocular, genital) with variable skin involvement: absent in one case, a solitary palm ulcer in another, and widespread rash in the third. One patient required two hospitalizations within a six-month interval, confirming the possible relapsing phenotype of RIME. Another patient developed pneumonia, sepsis, and systemic inflammation. All received macrolide therapy, antifungals, mucosal supportive care, and systemic management as indicated. Recovery occurred within 10-21 days, with one patient exhibiting skin hyperpigmentation. These cases illustrate the heterogeneity of RIME, emphasize the importance of prompt recognition, etiology confirmation, and multidisciplinary management. RIME is a rare clinical condition in pediatric population, an uncommon but significant mucocutaneous clinical entity, important to be acknowledged by clinicians as a complication and/or extra-pulmonary manifestation of <i>M. pneumoniae</i> infection.