Primary cutaneous histoplasmosis difficult to treat in immunocompetent patient: case report and literature review

Abstract

Histoplasmosis is an infection caused by the dimorphic fungus Histoplasma capsulatum. The disease is endemic in several regions of tropical and temperate climate. The fungus presents opportunistic behavior, causing widespread infection in immunocompromised patients, resulting from complication of primary pulmonary infection, due to exogenous reinfection or reactivation of a quiescent source. In immunocompetent individuals, approximately 95% of pulmonary infections are asymptomatic. However, prolonged exposure to high amount spores may lead to acute or chronic lung infection. Due to the low amount of inoculum, primary cutaneous histoplasmosis caused by traumatic implantation is extremely rare and effectively treated with triazoles. Thus, the present study aims to report a case of primary cutaneous histoplasmosis that is difficult to treat in an immunocompetent patient, and to review the literature on the incidence of drug-resistant Histoplasma capsulatum strains in clinical practice.

Figure 1. Erythematous papular lesion

Figure 2. Histoplasma capsulatum yeast form stained by periodic acid Schiff (A) and Grocott-Gomori methenamine silver (B)

Figure 3. Plain chest radiography in posteroanterior (A) and lateral (B) views

Figura 1. Lesão eritêmato-papulosa

Figura 2. Forma leveduriforme de Histoplasma capsulatum corada pelo ácido periódico de Schiff (A) e pela prata metenamina de Gomori-Grocott (B)

Figura 3. Radiografia simples do tórax em posição posteroanterior (A) e lateral (B)