Histoplasmosis

• Histoplasmosis encompasses a spectrum of clinical manifestations in the fewer than 5% of infected persons who are symptomatic.
• Clinical manifestations may be classified according to:
  • site (pulmonary, extrapulmonary, or disseminated)
  • duration of infection (acute, chronic)
  • pattern of infection (primary versus reactivation)

• Acute pulmonary histoplasmosis is an influenza-like illness that is characterized by nonpleuritic chest pain, pulmonary infiltrates, and hilar adenopathy. Symptoms persist for 2 or 3 days to 2 weeks.
• Erythema nodosum can occur in adolescents, but erythema nodosum and chronic pulmonary histoplasmosis are uncommon in children. Primary cutaneous infections can occur after trauma.
   
• Acute disseminated histoplasmosis is most common in children whose cell-mediated immunity is impaired:
  • human immunodeficiency virus (HIV) infection
  • solid-organ transplant recipients
  • infants younger than 1 year of age.
• Features include prolonged fever, failure to thrive, cough, hepatosplenomegaly, adenopathy, pneumonia, skin lesions, and pancytopenia. Central nervous system involvement is common.

• Chronic disseminated infection is rare.
• Histoplasmosis may reactivate years after primary infection in isolated tissues, particularly in the central nervous system, adrenal glands, and mucocutaneous surfaces, as well as in other sites.
• Disseminated or extrapulmonary histoplasmosis is an acquired immunodeficiency syndrome–defining condition in an HIV-infected person. Histoplasmosis may be diagnosed by culture, antigen detection in body fluids, or serology. The histoplasmin skin test is used primarily for epidemiologic purposes. 

References:
American Academy of Pediatrics. Histoplasmosis. In: Pickering LK, ed.
2000 Red Book: Report of the Committee on Infectious Diseases. 25th
ed. Elk Grove Village, Ill: American Academy of Pediatrics;
2000:319-321