A 29-year-old woman presented to the emergency department with progressive conjunctivitis, skin rash, and oral and genital mucosal lesions. She was febrile to 102°F (38.9°C), and laboratory results revealed an elevated white blood cell count of 15 × 109/L (reference range 4–11). She had no significant medical history, and was working as a pediatric nurse in an elementary school.
Two weeks before presentation, she developed a fever, productive cough, and myalgia, followed by a scattered maculopapular rash (Figure 1A), painful oral ulcers (Figure 1B), vaginal ulcers, and conjunctivitis. She reported a similar but milder episode about 1 year earlier after a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.
(A) Scattered pinkish-red macules and papules, some with central crusting and some with a targetoid appearance, on the skin of the patient’s back. The inset shows a closer view of the targetoid lesions on the chest. (B) Diffuse erythema and sloughing of the gingiva and buccal mucosa with hemorrhagic crusting of the lip vermilions.
The differential diagnoses included toxic epidermal necrolysis, Stevens-Johnson syndrome, and reactive infectious mucocutaneous eruption (RIME). The patient’s preceding respiratory infection and predominant mucositis involving the oral, ocular, and genital mucosae with limited skin involvement argued against a drug reaction.
Polymerase chain reaction testing of the patient’s sputum was positive for Mycoplasma pneumoniae, which supported a diagnosis of RIME.
The patient was hospitalized for 9 days, treated with intravenous and topical corticosteroids plus azithromycin, and discharged on a short prednisone taper. Her symptoms completely resolved within 1 month.
RIME
RIME is an acute mucocutaneous reaction most commonly triggered by M pneumoniae infection. Initially called M pneumoniae–induced rash and mucositis in 2015, the broader term reactive infectious mucocutaneous eruption is now used because it encompasses similar eruptions caused by other infectious agents, including influenza, Chlamydophila pneumoniae, enterovirus, rhinovirus, and SARS-CoV-2 (which causes COVID-19).1–3
Previously, RIME was thought to be within the same spectrum as erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis.4 However, erythema multiforme is a hypersensitivity reaction characterized by acrally distributed target (“bull’s eye”) lesions and limited mucosal involvement, and is typically associated with herpes simplex virus.1 Stevens-Johnson syndrome and toxic epidermal necrolysis are medication-induced reactions that cause extensive epidermal necrosis and detachment. RIME differs as it is most commonly associated with a respiratory infection, predominant mucosal involvement, and a generally milder course.1,4
Children and adolescents are primarily affected, but RIME can also be seen in adults.1–4 An infectious prodrome of fever, cough, or malaise is followed within a week by the hallmark painful erosions that affect 2 or more mucosal sites, most often oral, genital, and ocular. Ocular findings include conjunctivitis, conjunctival pseudomembranes, and photophobia. Cutaneous eruptions are sparse and may appear polymorphic (macules, vesicles, bullae, or target-like lesions).1,2,4
Chance of recurrence
Recurrence happens in 8% to 48% of cases, often within a year.1,5 Severity varies; our patient experienced a mild initial episode after having COVID-19 and a more severe recurrence after M pneumoniae infection, which required hospitalization.
Management is supportive
There are no standardized treatment guidelines for RIME. Supportive care includes topical corticosteroids, pain control, and adequate hydration and nutrition.2,4 Systemic corticosteroids may be considered for moderate-to-severe mucocutaneous manifestations,2,5 as was the case for this patient. Antibiotics can be used when a specific bacterium, such as M pneumoniae, is identified.2,4,5 Immunomodulators like intravenous immunoglobulin or cyclosporine may also help in severe cases.
THE BOTTOM LINE
RIME is distinct from erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis. Recognizing its characteristic mucosa-dominant pattern and infectious triggers prevents misdiagnosis and guides supportive, individualized treatment.
DISCLOSURES
The authors report no relevant financial relationships which, in the context of their contributions, could be perceived as a potential conflict of interest.
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REFERENCES
- 1↵Canavan TN, Mathes EF, Frieden I, Shinkai K. Mycoplasma pneumoniae– induced rash and mucositis as a syndrome distinct from Stevens-Johnson syndrome and erythema multiforme: a systematic review. J Am Acad Dermatol 2015; 72(2):239–245. doi:10.1016/j.jaad.2014.06.026
- 2↵Ramien ML. Reactive infectious mucocutaneous eruption: Mycoplasma pneumoniae-induced rash and mucositis and other parainfectious eruptions. Clin Exp Dermatol 2021; 46(3):420–429. doi:10.1111/ced.14404
- 3↵Lowell JA, Wright J, Eisenberg S, Teperman J, Dastagir M. Rash from the past: a case of recurrent reactive infectious mucocutaneous eruption triggered by common coronavirus. JAAD Case Rep 2024; 47:26–29. doi:10.1016/j.jdcr.2024.02.013
- 4↵Lofgren D, Lenkeit C. Mycoplasma pneumoniae-induced rash and mucositis: a systematic review of the literature. Spartan Med Res J 2021; 6(2):25284. doi:10.51894/001c.25284
- 5↵Pan CX, Hussain SH. Recurrent reactive infectious mucocutaneous eruption: a retrospective cohort study. J Am Acad Dermatol 2023; 89(2):361–364. doi:10.1016/j.jaad.2023.03.027
