Actinomycosis is a bacterial infection caused by Actinomyces species. It usually occurs following a break in the skin or mucous membranes that allows the bacteria to enter and form lumpy masses or granulomas. Symptoms vary depending on the infected area but may include lumps, draining sinuses, fever, and weight loss. Diagnosis involves culture, biopsy or imaging tests. Treatment involves long-term high dose antibiotics such as penicillin for several months to over a year to prevent recurrence or relapse. Prevention focuses on good oral hygiene and prompt treatment of wounds.