Authors: Issariya Kitwatthanachai , Narumol Silpa-archa

Abstract

Background: Mycoplasma pneumoniae (M. pneumoniae) is one of the most common causes of atypical pneumonia in
pediatric and adult populations worldwide. It can also affect many other organs including neurological, cardiac, hematologic,
gastrointestinal, renal, osteoarticular, ocular, and cutaneous involvement. Mycoplasma pneumoniae-related cutaneous vasculitis is an infrequent manifestation. Several cases of secondary cutaneous leukocytoclastic vasculitis (LCV) associated with M. pneumoniae have been publicly reported in both English and foreign languages.
Case Presentation: This report details the case of a 44-year-old Thai male presented with high-grade fever accompanied by
generalized erythematous papules, patches, and some pustules for 3 days with no chest symptoms. He was treated with
ceftriaxone, doxycycline, and clindamycin for 5 days without clinical improvement. However, histopathological and direct
immunofluorescence tests later confirmed a diagnosis of LCV. Serological tests showed positivity for M. pneumoniae. The
regimen was then changed to azithromycin 500 mg daily for 5 days and the lesions showed remarked improvement without
scarring.
Conclusion: The importance of recognizing and addressing the atypical presentations of M. pneumoniae in febrile patients with cutaneous vasculitis is imperative to guide targeted treatment decisions, thus facilitating rapid clinical improvement.

Keywords: Case report, M. pneumoniae-associated vasculitis, cutaneous leukocytoclastic vasculitis, Mycoplasma pneumoniae infection, atypical bacterial infection, secondary vasculitis, extrapulmonary manifestations.