Case Report: Mycoplasma pneumoniae-induced rash and mucositis in a child.

RATIONALE: Mycoplasma pneumoniae (MP) is a common pathogen responsible for pediatric community-acquired pneumonia. MP infection can also induce extrapulmonary manifestations, including mucocutaneous eruptions. Mycoplasma pneumoniae-induced rash and mucositis (MIRM) is a relatively newly described entity distinct from erythema multiforme (EM), Stevens-Johnson syndrome (SJS), and toxic epidermal necrolysis (TEN). However, MIRM remains underrecognized, with limited cases reported in China.

PATIENT CONCERNS: A previously healthy 10-year-old boy presented with fever, cough, severe mucositis (oral and ocular involvement), and disseminated rash for 5 days.

DIAGNOSES: The patient was diagnosed with Mycoplasma pneumoniae-induced rash and mucositis (MIRM), confirmed by clinical presentation and laboratory detection of MP nucleic acid.

INTERVENTIONS: The treatment regimen for the patient included intravenous azithromycin, methylprednisolone at a dosage of 1 mg/kg/day, intravenous immunoglobulin (IVIG), vitamin C, oral antihistamines, topical treatments for mucosal care, ophthalmic ointment, and calamine lotion. After 1 week, due to a persistent cough and a positive Mycoplasma pneumoniae (MP) nucleic acid test, the patient's treatment was transitioned to oral doxycycline.

OUTCOMES: The patient experienced significant clinical improvement after 14 days, with resolution of rash, mucosal lesions, and cough. Follow-up tests confirmed clearance of MP nucleic acid and normalization of inflammatory markers.

LESSONS: MIRM is a distinct mucocutaneous entity associated with MP infection. Pediatricians should recognize its clinical presentation early to provide prompt targeted therapy and supportive care, thus preventing complications.