Infection occurs only when tissue is broken, enabling the bacteria to enter deeper tissues.
Abscesses form in various areas, such as the intestine or face, causing pain, fever, and other symptoms.
Symptoms suggest the diagnosis, and doctors confirm it by identifying the bacteria in a sample of infected tissue.
Abscesses are drained, and antibiotics are given.
With prompt diagnosis and appropriate treatment, most people recover fully.

Actinomyces bacteria do not require oxygen to live. That is, these bacteria are anaerobes.
Actinomyces bacteria cause infection only when the surface of the tissue on which they reside is broken, enabling them to enter other, deeper tissues, which have no defenses against them. As the infection spreads, scar tissue and abnormal channels (called fistulas or tracts) form. After months to years, fistulas may eventually reach the skin and allow pus to drain. Pockets of pus (abscesses) may develop in the chest, abdomen, face, or neck.
Men are affected most often, but actinomycosis occasionally develops in women who use an intrauterine device (IUD).