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Reactive infectious mucocutaneous eruption in Adult
Other Resources UpToDate PubMed

Reactive infectious mucocutaneous eruption in Adult

Contributors: Amanda Tillmann MD, Susan Burgin MD
Other Resources UpToDate PubMed

Synopsis

Reactive infectious mucocutaneous eruption (RIME) is a relatively uncommon mucocutaneous condition resulting from Mycoplasma pneumoniae infection and, less commonly, other viral and bacterial infections. It is characterized by prominent mucositis. Initially, RIME was designated as MIRM (Mycoplasma-induced rash and mucositis), given that all then-recognized cases were associated with M pneumoniae. With the recognition that other infectious agents (including Chlamydia pneumoniae, human parainfluenza virus 2, rhinovirus, adenovirus, enterovirus, human metapneumovirus, and influenza B virus) can cause a similar clinical picture, the term RIME was adopted. A case of RIME induced by COVID-19 (SARS-CoV-2 infection) has been reported.

RIME secondary to M pneumoniae (ie, MIRM):
  • Usually seen in children and adolescents (mean age of approximately 12 years); however, adults of middle age and younger individuals may also be affected.
  • Cases occur more commonly in males than females (ratio of 2:1).
  • Prodromal symptoms of cough, fever, and malaise precede mucocutaneous manifestations by approximately a week. Mucositis is a prominent feature and is usually associated with a sparse, polymorphic eruption.
  • Complications may include hematemesis, epiglottitis, subcorneal pustulosis, pneumomediastinum, pericardial effusion, and hepatitis.
  • Ocular sequelae include conjunctival shrinkage, corneal ulceration, blindness, synechiae, dry eyes, and loss of eyelashes. Oral or urogenital adhesions are less common. Pulmonary complications such as restrictive lung disease and chronic obliterative bronchitis have also been observed in MIRM patients.
  • MIRM is very rarely fatal and has a reported mortality rate of 3%, occurring in cases with significant respiratory disease. Most patients make a full recovery, and both long-term complications and recurrences are infrequent.
The pathophysiology underlying RIME remains poorly defined. Direct cytotoxic injury, autoimmune-mediated injury, and immune complex-mediated vascular injury have all been proposed as potential etiological mechanisms. It is speculated that a genetic predisposition is also important. Of note, it has been postulated that autoantibodies produced as a result of molecular mimicry between M pneumoniae and endogenous proteins cross-react with specific self-antigens that are most abundant in mucous membranes. This theory helps explain why mucositis is such a salient feature.

Codes

ICD10CM:
B96.0 – Mycoplasma pneumoniae [M. pneumoniae] as the cause of diseases classified elsewhere

SNOMEDCT:
406595002 – Infection caused by Mycoplasma pneumoniae

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Diagnostic Pearls

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Differential Diagnosis & Pitfalls

SJS / TEN
  • The cutaneous involvement of RIME tends to be much less extensive than in SJS and TEN (<10% of body surface area is usually affected).
  • The cutaneous lesions of RIME are usually distributed in acral regions compared to SJS and TEN, which exhibit a more central distribution of lesions.
  • The desquamation associated with SJS and TEN is absent in RIME (Nikolsky sign is negative).
  • RIME has a much milder course than SJS and TEN, eg, ICU admission is less commonly required.
  • Absence of exposure to a culprit drug favors RIME, as most cases of SJS and TEN are drug-related.
  • Evidence of atypical pneumonia, including respiratory symptoms, lung auscultation findings, M pneumoniae serology, polymerase chain reaction (PCR), and chest x-ray results, may help support RIME diagnosis.
Erythema multiforme (EM)
  • The classic target lesions occurring in an acral distribution that are typical of EM are less common in RIME.
  • Unlike EM, cutaneous lesions may be absent in RIME.
  • Evidence of atypical pneumonia, including respiratory symptoms, lung auscultation findings, M pneumoniae serology, PCR, and chest x-ray results, may help support RIME diagnosis.
Fixed drug eruption
  • Typical round morphology is diagnostic.
  • RIME lacks a temporal relationship to drug exposure.
Multisystem inflammatory syndrome in adults (MIS-A)

Best Tests

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Therapy

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References

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Last Reviewed:02/14/2022
Last Updated:02/15/2022
Copyright © 2022 VisualDx®. All rights reserved.
Reactive infectious mucocutaneous eruption in Adult
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A medical illustration showing key findings of Reactive infectious mucocutaneous eruption : Acral distribution, Targetoid configuration
Copyright © 2022 VisualDx®. All rights reserved.