Reactive Infectious Mucocutaneous Eruption Associated With Mycoplasma pneumoniae in a 11-Year-old Boy

To the Editors: Reactive infectious mucocutaneous eruption (RIME) is a significant mucocutaneous condition predominantly affecting children and adolescents following respiratory tract infections, particularly those caused by Mycoplasma pneumoniae. It is primarily characterized by severe oral mucositis, conjunctivitis and involvement of the urethra. Cutaneous manifestations are usually mild and often include vesiculobullous eruptions. Unlike Stevens–Johnson syndrome and toxic epidermal necrolysis, RIME is typically associated with an infectious trigger, has a less severe clinical course and is generally associated with a favorable prognosis.1 We report a case of an 11-year-old previously healthy male presenting with mucositis in the oral cavity, penile ulceration, fever and cough. His fever and cough began 10 days prior, leading to a consultation three days earlier, during which he was prescribed oral amoxicillin-clavulanate (12-hour intervals). Following the third dose of the antibiotic, painful oral and penile mucosal lesions emerged, prompting referral to our clinic. On examination, the patient had mucositis in the oral cavity, bilateral nonpurulent conjunctivitis and an erythematous ulceration at the glans penis (Fig. 1). Bilateral crackles were auscultated in the lower lung lobes. Penile examination revealed mucositis around the glans and urethral meatus, accompanied by dysuria requiring catheterization. Laboratory investigations, including complete blood count, biochemistry, C-reactive protein and urinalysis, were performed. The patient’s oral intake was inadequate, necessitating intravenous fluid therapy. Chest radiograph revealed increased infiltrates in the middle and lower zones of the right lung. Echocardiography ruled out Kawasaki disease. The ophthalmologic evaluation identified no ocular involvement.FIGURE 1.: Illustrations of the clinical features and progression through treatment. A and B: Conjunctivitis, (C and D) hemorrhagic crusted lip, (E and F) Post-treatment healing appearance of eyes and lips.Given the mucocutaneous lesions, recent antibiotic exposure and multisystem involvement, Stevens–Johnson Syndrome was considered. However, evaluations by ophthalmology and allergology did not support this diagnosis. The presence of pneumonic infiltrates raised suspicion of RIME secondary to Mycoplasma pneumoniae infection. Multiplex respiratory polymerase chain reaction confirmed Mycoplasma pneumoniae positivity, and serological tests showed elevated Mycoplasma pneumoniae IgM (>200.0, positive) and IgG (>74, positive). Additional immune parameters were notable for elevated total IgE (390.6 U/mL) with normal IgA, IgG and IgM levels. The patient was treated with oral clarithromycin for the infection and fluconazole for oral lesions. Methylprednisolone (1 mg/kg/d) was initiated and continued for 5 days. The patient showed rapid improvement, with oral lesions healing and systemic symptoms resolving. Fluid therapy was tapered, and catheterization was discontinued on day 2 of hospitalization. The patient’s mucosal lesions fully resolved, and he was discharged in good condition with no residual symptoms. Treatment for RIME is primarily supportive and involves a multidisciplinary team, including pediatricians, dermatologists, ophthalmologists and pain specialists. Saline-soaked gauze and soft paraffin are used for lip care to prevent crusting and pain, while topical anesthetics like oral lignocaine improve oral intake.2 Urethral lesions may benefit from paraffin and topical anesthetics, and catheterization is considered if urinary retention occurs. Ocular lubrication and regular ophthalmology reviews help prevent complications such as conjunctival ulceration. While antibiotics treat the underlying infection, they do not alter RIME’s course. Immunosuppressants are reserved for uncertain diagnoses or worsening symptoms after conservative management.3,4