Pulmonary actinomycosis associated with poor oral hygiene: A case report

Pulmonary actinomycosis, a rare and chronic infection caused by Actinomyces species, involves anaerobic gram-positive bacteria that are part of the oral cavity’s normal flora. Thoracic involvement, accounting for approximately 15% of all actinomycosis cases, typically results from aspiration of oropharyngeal secretions. We report the case of a 36-year-old man with poor oral hygiene and severe dental decay who presented with a month-long history of chronic cough, hemoptysis, malodorous sputum, weight loss, and pleuritic chest pain. Imaging identified a cavitary lesion in the left upper lobe, initially raising concern for infectious or malignant etiologies. Bronchoscopic sampling confirmed pulmonary actinomycosis through histological identification of sulfur granules. The patient responded favorably to high-dose intravenous penicillin followed by oral antibiotics. This case underscores the diagnostic challenges of pulmonary actinomycosis, the importance of oral hygiene as a modifiable risk factor, and the need for a multidisciplinary management approach.