Leukocytoclastic vasculitis (LCV) is an immune complex–mediated small-vessel vasculitis commonly associated with infections, medications, autoimmune diseases, and malignancy. Although atypical respiratory pathogens have been linked to several extrapulmonary dermatologic manifestations, reports of LCV occurring in association with Chlamydia pneumoniae infection remain rare. We describe a case of biopsy-proven LCV occurring in temporal association with C. pneumoniae respiratory infection in a 36-year-old woman who developed upper respiratory symptoms followed two weeks later by a rapidly progressive purpuric rash involving the lower extremities, abdomen, and upper extremities. Associated symptoms included arthralgias, bilateral foot edema, abdominal pain, nausea, and vomiting. Chest radiography demonstrated patchy left upper lobe airspace opacity, and respiratory pathogen testing was positive for Chlamydia pneumoniae . Extensive infectious and autoimmune evaluation was otherwise unrevealing. Skin punch biopsy confirmed leukocytoclastic vasculitis with negative direct immunofluorescence studies. The patient was treated with doxycycline and systemic corticosteroids, resulting in marked clinical improvement. This case highlights the diagnostic challenges of infection-associated vasculitis, which may mimic primary autoimmune disease because of systemic symptoms and transient autoantibody positivity. Although causality cannot be established, C. pneumoniae was considered a possible associated infectious trigger given the temporal association between respiratory illness and rash onset, compatible radiographic findings, positive respiratory pathogen testing, and exclusion of alternative etiologies. Clinicians should consider atypical respiratory pathogens in the differential diagnosis of small-vessel vasculitis following respiratory illness.
Vora et al. (Thu,) studied this question.