Skin lesion of Coccidioidomycosis

Definition:

A disease caused by inhaling a fungus from the soil in certain parts of the southwestern U.S., Mexico, and Central and South America. California's San Joaquin Valley is endemic for coccidioidomycosis (it occurs there commonly); the pulmonary form is often called San Joaquin Valley Fever.

Causes, incidence, and risk factors:

A coccidioidomycosis infection is caused by inhaling the spores of a mold-like fungus (Coccidioides immitis) that is found in the soil of hot, dry regions. About 60% of the infections cause no symptoms and are only recognized by a positive coccidioidin skin test. In the remaining 40%, symptoms primarily involve the lung (pulmonary) and nonspecific general symptoms. These may range from mild cold or flu-like symptoms to severe illness. Darker skinned people generally have more severe symptoms. Immunocompromised individuals such as those with AIDS may experience disseminated coccidioidomycosis which includes skin lesions.

Incubation is 10 to 30 days. Nonspecific skin rashes, a scarlet fever-like rash or erythema nodosum, often develops within a week of onset of other symptoms. This rash is not significant and may actually indicate a healthy immune response. The severe form of cutaneous coccidioidomycosis develops later, after an initial infection has become chronic or disseminated. This rash begins as red papules, often on the face scalp and neck. These papules may develop into ulcers and finally into highly vascular warty lumps (granulomas). Abscesses may also form. The skin lesion often resembles those of other fungal skin infections such as blastomycosis and histoplasmosis.