CUTANEOUS MANIFESTATIONS OF SYSTEMIC MYCOSES

BLASTOMYCOSIS

Initial work by Gilchrist led to the theory by Martin and Smith65, 66 in 1939 that there were two forms of blastomycosis, cutaneous and pulmonary. This mistaken notion was not corrected until 1951 when the clinical pathologic studies of Schwartz and Baum⁸⁶ demonstrated that like the other systemic fungal diseases, blastomycosis is a primary pulmonary infection that arises after inhalation of conidia. The disease is found in the Ohio and Mississippi River valleys, and the Great Lakes region

COCCIDIOIDOMYCOSIS

Disseminated coccidioidomycosis was initially described in South America in the late 1800s as a rare and fatal disseminated infection. It was not appreciated to be caused by the same agent as "San Joaquin Valley fever," a common self-limited infection, until 1929 when a medical student inhaled a cloud of arthroconidia while working in a laboratory of Dickson. The student developed pulmonary disease with erythema nodosum rather than disseminated disease. Dickson and a public health physician

HISTOPLASMOSIS

There are two forms of histoplasmosis; each of these infections has a distinct epidemiology, clinical presentation, and histopathology.48, 49, 63 Histoplasmosis is common in North and Central America and is caused by H. capsulatum. African histoplasmosis, caused by H. capsulatum var. duboisii, is found in central Africa. Although these organisms were originally thought to be separate species, Kwon-Chung⁵⁸ has demonstrated that they are variants of the same species by mating studies.

AFRICAN HISTOPLASMOSIS

The natural habitat of H. capsulatum var. duboisii has not been reported and efforts to isolate the agent from soil have been successful only rarely.³ Outbreaks similar to those of other systemic fungal diseases have not been reported.27, 63 Those cases reported outside of Africa have occurred in former residents, and this implies that endogenous reactivation occurs.1, 5

Cutaneous lesions are the predominant manifestation of African histoplasmosis. Skin lesions may occur as the sole

PARACOCCIDIOIDOMYCOSIS

Paracoccidioidomycosis is seen in Latin American countries between 23°N (Mexico) and 34°S (Bolivia), with Brazil being the country with the highest incidence.⁷¹ It is restricted to regions characterized by constant temperatures and tropical to subtropical conditions. Outbreaks have not been reported, and the ecological niche is unknown. Skin testing surveys have aided in the elucidation of some epidemiology.¹⁹ It has been associated with agricultural rural communities, and armadillos and bats

SUMMARY

Systemic fungal diseases are primary pulmonary diseases caused by the dimorphic fungal pathogens, Blastomyces dermatitidis, Coccidioides immitis, Histoplasma capsulatum, or Paracoccidioides brasiliensis. Infection occurs after inhalation of the infectious form of fungus and may be acute, self-limited, or subclinical. Primary cutaneous infection occurs only after traumatic implantation of the fungus and is quite unusual. Erythema nodosum or erythema multiforme may accompany the acute form of the