What is the recommended treatment for Mycoplasma pneumoniae‑induced rash and mucositis (MIRM) in a pediatric patient with moderate to severe mucosal involvement?

Treatment of MIRM in Pediatric Patients

For pediatric patients with Mycoplasma pneumoniae-induced rash and mucositis (MIRM), supportive care is the cornerstone of management, combined with macrolide antibiotics (azithromycin 10 mg/kg day 1, then 5 mg/kg days 2-5) to treat the underlying infection, with consideration of immunomodulatory therapy (IVIG or cyclosporine) for severe mucosal involvement. 1, 2, 3

Understanding MIRM as a Distinct Entity

MIRM is a recently recognized clinical syndrome distinct from Stevens-Johnson syndrome or erythema multiforme, characterized by predominant mucositis (oral, ocular, and/or genital) with variable cutaneous involvement occurring 7-9 days after prodromal respiratory symptoms. 1, 2 The pathogenesis differs from drug-induced mucocutaneous reactions, involving either direct bacterial invasion or molecular mimicry-induced immune responses. 4

Antibiotic Treatment

First-Line Macrolide Therapy

• Azithromycin is the preferred macrolide at 10 mg/kg (maximum 500 mg) on day 1, followed by 5 mg/kg (maximum 250 mg) daily for days 2-5. 5, 6
• Alternative macrolides include clarithromycin 15 mg/kg/day divided in 2 doses or erythromycin 40 mg/kg/day divided in 4 doses. 7, 6
• Macrolides treat the underlying M. pneumoniae infection and may reduce the duration of symptoms when initiated early. 2

Alternative Antibiotics for Older Children

• For children ≥8 years old, doxycycline (2-4 mg/kg/day in 2 doses) is an alternative if macrolide resistance is suspected or documented. 7, 8
• Macrolide resistance rates vary geographically (0-15% in Europe/USA, up to 90-100% in Asia), which may necessitate alternative therapy. 8
• Fluoroquinolones (levofloxacin) are generally contraindicated in children due to cartilage toxicity concerns. 7

Supportive Care (Mainstay of Treatment)

Essential Supportive Measures

• Pain management with appropriate analgesics to facilitate oral intake and comfort. 1
• Intravenous hydration for patients unable to maintain adequate oral intake due to severe mucositis. 1, 3
• Mucosal care including gentle oral hygiene, saline rinses, and topical anesthetics for oral lesions. 1
• Ophthalmologic consultation for ocular involvement to prevent corneal complications and scarring. 1, 2

Monitoring Requirements

• Maintain oxygen saturation >92% if respiratory involvement is present. 6
• Monitor for cardiac complications including myopericarditis and conduction abnormalities (rare but reported). 4
• Reassess at 48-72 hours; fever may persist 2-4 days with atypical pathogens. 6

Immunomodulatory Therapy for Moderate to Severe Cases

IVIG Consideration

• Intravenous immunoglobulin (IVIG) has been used in multiple case reports for severe MIRM with extensive mucosal involvement. 2, 3
• Dosing typically follows standard protocols (1-2 g/kg), though no standardized guidelines exist. 2
• IVIG may be considered when mucositis is severe enough to compromise oral intake or when ocular involvement is progressive. 2

Cyclosporine as Emerging Option

• Cyclosporine A (CsA) showed rapid clinical resolution in a case series of 3 pediatric MIRM patients when initiated early. 3
• CsA may be particularly effective for severe mucosal disease, though evidence is limited to case reports. 3
• Consider early initiation in severe cases not responding to supportive care and antibiotics. 3

Corticosteroid Role

• Systemic corticosteroids have been used in some cases, though their efficacy remains unclear. 2
• The role of corticosteroids is controversial and not universally recommended, unlike in drug-induced SJS/TEN. 2

Clinical Pitfalls to Avoid

• Do not misdiagnose as Stevens-Johnson syndrome or Kawasaki disease—MIRM has distinct pathogenesis and may require different management. 2, 4
• Do not assume treatment failure prematurely—fever may persist 2-4 days with M. pneumoniae, unlike pneumococcal pneumonia where defervescence occurs within 24 hours. 6
• Do not overlook ocular complications—early ophthalmologic involvement prevents long-term sequelae including corneal scarring. 1, 2
• Do not use beta-lactams alone—M. pneumoniae lacks a cell wall and is intrinsically resistant to all beta-lactam antibiotics. 8

Prognosis and Follow-Up

• The majority of MIRM patients (81%) achieve full recovery with supportive care and appropriate antibiotics. 1
• Potential complications include ocular scarring, oral synechiae, and genital adhesions requiring long-term follow-up. 1
• Recurrence is possible, as documented in at least one case with both M. pneumoniae and C. pneumoniae triggers. 2