Macular Rash as a Presenting Symptom of Acute Q Fever: A Case Report

Q fever is a globally distributed zoonotic infection caused by Coxiella burnetii, exhibiting a broad clinical spectrum in both acute and chronic forms. While pneumonia, hepatitis, and endocarditis are well-recognized manifestations, cutaneous involvement remains poorly characterized and likely underreported.

A 63-year-old male metalworker was admitted with a 2-week history of high-grade fever, dyspnea, anorexia, intractable hiccups, and profound asthenia. Physical examination revealed a diffuse, nonpruritic, blanchable macular rash on the back and sacral region. Extensive microbiological and autoimmune investigations were negative. Chest imaging demonstrated bilateral pneumonia, mediastinal lymphadenopathy, and a small pericardial effusion. Skin biopsy showed mild acanthosis, dermal capillary congestion, and superficial lymphohistiocytic infiltrates. Serological testing confirmed acute Q fever, with elevated Phase II C. burnetii antibody titers. Oral doxycycline led to complete resolution of fever and rash. Serial serology demonstrated a progressive decline in antibody titers, and the patient remained symptom-free after 6 months.

This case highlights a rare parainfectious macular rash associated with acute Q fever-apparently the first reported in Italy. Cutaneous involvement in Q fever may represent a parainfectious immune-mediated reaction. Its nonspecific appearance and lack of a characteristic distribution pattern often delay diagnosis.

Clinicians should maintain a high index of suspicion for C. burnetii infection in patients with unexplained fever, pneumonia, and rash, even in the absence of direct animal exposure. Multidisciplinary evaluation and serial serology are pivotal for timely diagnosis, effective management, and monitoring of disease resolution.