Mycoplasma pneumoniae-Induced Mucocutaneous Rash: A New Syndrome Distinct from Erythema Multiforme? Report of a New Case and Review of the Literature

Mycoplasma pneumoniae-induced rash and mucositis: A new entity

Mycoplasma pneumoniae is a well-known cause of community-acquired pneumonia, mostly associated with dermatological manifestations especially with mucosal involvement and targetoid cutaneous lesions. For many years, it was considered among the spectrum of erythema multiforme. Recently, some authors have recommended the creation of a new syndrome called "mycoplasma-induced rash and mucositis." This new syndrome has distinct epidemiological, clinical and histological features making it different from drug-induced Stevens-Johnson syndrome, toxic epidermal necrosis and erythema multiforme. Herein, we report two patients with acute Mycoplasma pneumoniae respiratory tract infection presenting severe mucocutaneous lesions in accordance with this new syndrome.

Case Report: Clinical and Immunological Features of a Chinese Cohort With Mycoplasma-Induced Rash and Mucositis

Dermatological disorders are the most common extrapulmonary complications of Mycoplasma pneumoniae, of which Mycoplasma-induced rash and mucositis (MIRM) has recently been proposed to be a separate diagnostic entity. MIRM could easily be misdiagnosed as atypical Stevens-Johnson syndrome by clinicians due to the unawareness of this rare disease. We retrospectively reviewed the inpatient database from Jan. 2016 to Dec. 2019 of the Children's Hospital of Fudan University. In total, five patients (mean age 5.5 years, three male) matched the diagnostic criteria of MIRM. All patients had scattered lesions and more than two sites of mucosal involvement. The serum IgA level of three patients was higher than normal. Two patients had a significant decrease in peripheral blood CD3+ T and CD4+ T cells that improved with recovery. The percentage of TCRαβ+ CD4-CD8-T cells of Patient five was higher than normal. All patients received treatments with antibiotics and corticosteroids, 3 patients received intravenous immunoglobulin. Among five patients, three patients complained of dyspigmentation, and two patients had an uneventful recovery. MIRM is a separate entity with predominant mucosal involvement and excellent prognosis that more often affects younger patients. Excessive inflammatory reactions may lead to immune disorders, including lymphopenia and a redistribution of CD4+ T cells. We recommend that pneumonia accompanied by mucocutaneous eruptions, especially in young patients, should raise clinical suspicion of MIRM.