What is a classical feature of actinomycosis?

A classical feature of actinomycosis is the presence of multiple cutaneous fistulas. Actinomycosis is a chronic granulomatous infection caused by the bacterium Actinomyces, which is often found in the oral cavity. When the infection occurs, it can lead to the development of abscesses that may drain through the skin, resulting in the formation of multiple fistulas. These fistulas are typically characterized by their serosanguinous drainage, and their presence is one of the hallmark signs of this disease.

The other symptoms listed, like fever, severe headache, and joint pain, may be found in various other conditions but are not specific to actinomycosis. While fever can accompany an infection, it is not a defining feature of actinomycosis. Likewise, severe headache and joint pain are not commonly associated with this infection and lack the specificity that the presence of multiple cutaneous fistulas provides. The key distinction lies in the unique presentation of the fistulas, which not only helps in diagnosing actinomycosis but also illustrates the chronic nature of the infection.