Skin lesion of histoplasmosisSkin lesion of histoplasmosis is a symptom of Histoplasmosis, an infection caused by inhaling the spores of the fungus Histoplasma capsulatum, which are in bird and bat droppings and are common along river valleys. If the skin lesion is seen in the setting of disseminated histoplasmosis, a biopsy of the skin lesion may show the associated fungus. Other findings
such as erythema nodosum and erythema multiforme are manifestations of the body's inflammatory reaction and usually do not have fungus in them.
Histoplasmosis is caused by a fungus found in the central and eastern U.S., eastern Canada, Mexico, Central America, South America, Africa, and southeastern Asia. The fungus has been linked to exposure to birds, bird feathers, and bats. Histoplasmosis, a type of fungus, exists as a spore in the soil in endemic areas. Exposure is usually through inhalation of the spore. The spore germinates into the fungus which can cause primary pulmonary histoplasmosis (a type of pneumonia) or spreads from the lungs to other areas of the body. Most cases are mild or asymptomatic. The symptoms most commonly occur as a nonspecific respiratory infection similar to a cold or flu. It can also occur as an acute or progressive disorder, as disseminated (widespread) disease, or as a chronic disorder. The acute disease may occur in epidemics, with illness lasting for 1 to 6 months, but it is rarely fatal. The acute progressive Histoplasmosis continues to worsen and is often fatal within 6 weeks or less. It involves the liver, spleen, and all the organs of the body. Skin lesions are common with progressive Histoplasmosis.
Skin lesions may also occur with disseminated and chronic Histoplasmosis. The disseminated disease commonly occurs in persons with immune system disorders such as AIDS and is often rapidly fatal. The chronic disease may occur in immunosuppressed persons or in elderly persons with COPD and mild immune compromise, and usually confines symptoms to the lungs until it is in its terminal stages. The chronic or disseminated disease can also occur in people with normal immune systems although this is rare. The associated skin lesion usually presents as a lesion on the mouth or inner cheek. Like other mouth ulcers, it may interfere with the ability to eat and drink because of discomfort.
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. The treatment includes treatment for systemic disease and symptomatic relief of the mouth ulcer. Systemic disease is treated with antifungal medications, intravenously (in a vein) or orally (by mouth). These medications include amphotericin B, ketoconazole, fluconazole, and other potent (and often dangerous) antifungal agents.
Gentle, thorough oral hygiene helps to decrease pain and reduces the risk of infection of the mouth ulcer. Topical antihistamines, antacids, steroids or other medications may be recommended to soothe the area. Avoid hot or spicy foods, which often increase the mouth pain. Prevention of histoplasmosis involves minimizing exposure to dust in contaminated environments -- such as chicken coops and bat caves. Wear protective equipment such as masks if you work in these environments.