Reactive infectious mucocutaneous eruption

Background

• RIME is a mucosal or mucocutaneous eruption following Mycoplasma pneumoniae infections
  • Other suspected causative infections include Chlamydophila pneumoniae, human metapneumovirus, human parainfluenza virus 2, rhinovirus, enterovirus, influenza A and B, COVID‐19, and adenovirus
• Similar to a postinfectious Stevens-Johnson syndrome, though more common in younger patients with notable mucosal findings and absent or minimal cutaneous findings

Clinical Manifestations

• Prodrome of fever, cough, and malaise lasting 3 to 13 days (median 8 days)
• Usually two or more mucosal surfaces involved, including oral (most common, in 95% of cases), ocular (next most common, in around 90%), urogenital (about 60%), and anal or esophageal surfaces (least common)
  • Oral: erosions, ulcers, vesicular or vesiculobullous lesions, or desquamation
  • Ocular: bilateral conjunctivitis (often purulent), conjunctival injection, or hyperemia
  • Urogenital: more commonly described in female patients
• May have skin involvement, though absent in 1/3 and sparse in 1/2 of cases
  • Vesiculobullous lesions are most common, followed by targetoid, papular, macular, and morbilliform
  • Present on extremities and/or trunk

Differential Diagnosis

• SJS/TEN

Investigations

• Routine investigations
• Consider chest x-ray to assess for respiratory infection
• Consider NP swab for viral PCR, Mycoplasma pneumoniae, and Chlamydophila pneumoniae
• May need biopsy, though on biopsy it is indistinguishable from SJS/TEN

Diagnosis

• Evidence of an infectious trigger, with at least 2 of:
  • Non-contributory medication history
  • Erosive mucositis affecting 2 or more sites
  • Vesiculobullous lesions or atypical targets affecting less than 10% of body surface area
• Evidence of an infectious trigger can include history of cough, fever, malaise, and arthralgias in the preceding 7 to 10 days, or signs of respiratory infection on clinical examination
• Supporting features include prodromal symptoms in the preceding 7 to 10 days, or histology ruling out other diagnoses

Management

• Not well studied
• Supportive care: fluids, nutrition, and pain management
• Low threshold for Dermatology consult to help with diagnosis and treatment
• Consider Ophthalmology consult for patients with ocular involvement
• Often receive antibiotics, particularly when considering a bacterial infectious trigger
• In case reports or case series, patients have received high-dose corticosteroids (1-2 mg/kg IV methylprednisolone or 1 mg/kg p.o. prednisone for 3 to 5 days +/- taper), IVIG, cyclosporine, and etanercept

Further Reading

• Diagnosis and management of reactive infectious mucocutaneous eruption. J Hosp Med. 2025 Nov;20(11):1212-1216. doi: 10.1002/jhm.70099. Epub 2025 Jul 7. PMID: 40619921; PMCID: PMC12579755.