ZSFG Report 3.13.18: This ain’t for the best, my histo’s never been worse, so…

Thank you to Kendra M and Annie Luetkemeyer for discussing the case of women with HIV/AIDS and disseminated histoplasmosis, manifesting as a diffuse papular rash and diffuse lymphadenopathy. We learned some great information about etiology, diagnostics, and classic presentations of histoplasmosis.

Histoplasmosis: Epidemiology

  • Most common endemic mycosis in patients with HIV/AIDS; overall declining though in HIV positive patients given success with ART.
  • Inhaled from soil that contains bird and bat droppings.
  • In the US, classically thought about in the Mississippi, Ohio and St Lawrence River valleys. In this hemisphere, also seen in Caribbean and Central America.
  • Worldwide, Histo has been found in all continents except for Antarctica!


Histo: Clinical presentation

Both immunocompetent and immunocompromised hosts can have histoplasmosis infection

  • Immunocompetent host – usually presents as a mild pulmonary infection
  • Immunocompromised host – especially with advanced AIDS (and CD4 less than 200), can have systemic multi organ involvement.
    • Systemic: Fever and weight loss very common in disseminated histoplasmosis
    • Cutaneous: 10-15% of pts with disseminated histo have skin involvement, usually nodules and papules diffusely
    • Gastrointestinal disease: 70% of pts with disseminated histo have GI involvement; lesions include ulcers most often in colon or ileum.
    • Hepatic and splenic involvement : infiltrative liver disease
    • Pulmonary: productive cough, apical infiltrates with cavitation
    • CNS: 5-20% of cases, meningitis or focal brain lesions
  • Common laboratory signs
    • Pancytopenia – can infiltrate bone marrow
    • Isolated elevated alk phos – infiltrative liver picture
    • Ferritin – frequently very elevated in s/o histo infection


How to diagnoses Histoplasmosis

  • Big picture: maintain high clinical suspicion, as may have false negatives in multiple modalities of testing for histoplasmosis.
  • Top three tests for Histo diagnosis:
    • Antigen testing: Urine Histo Ag: 75% sensitive in nonimmunocompromised, and 95% sensitive in immunocompromised.
    • Biopsy of involved organs with PAS stain.
    • Antibody testing: immunodiffusion test and complement fixation are ~90% sensitive in immunocompetent, ~70% sensitive in immunocompromised pts with disseminated disease. May be negative in acutely ill patients and in those who are immunosuppressed.









One thought on “ZSFG Report 3.13.18: This ain’t for the best, my histo’s never been worse, so…”

  1. As a former chief resident, I really appreciate these posts and the hard work it takes to keep the blog updated.

    I wanted to especially commend you on the title of this talk. I burst out laughing once I got the reference.



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