Chronic pulmonary histoplasmosis – a scoping literature review

Chronic pulmonary histoplasmosis (CPH) is an uncommon manifestation of Histoplasma infection with features similar to pulmonary tuberculosis (TB). In endemic areas, it may be misdiagnosed as smear-negative pulmonary TB. Historical case series mainly from patients with presumed TB described a high frequency of cavitation and poor prognosis, likely resulting from delayed presentation. More recent reports suggest CPH can present with nodules, lymphadenopathy or infiltrates, with cavities a less common feature. Emphysema is the main risk factor for cavitary CPH. CPH is therefore an umbrella term, with chronic cavitary pulmonary histoplasmosis and Histoplasma nodules the main long term manifestations in non-immunocompromised individuals. Diagnosis relies on a high index of suspicion, use of fungal culture of respiratory samples, antibody testing and compatible radiological picture. Treatment with itraconazole for at least 12 months is recommended. Morbidity from CPH results from slow progression of cavities and gradual loss of lung function especially if not recognised and treated. Studies on the epidemiology of CPH are needed in order to improve understanding of the disease.