Cryptococcosis is a potentially fatal fungal infection of mainly the lungs, presenting as a pneumonia, and in the brain, where it appears as a meningitis.

[5] When the brain is infected, symptoms include headache, fever, neck pain, nausea and vomiting, light sensitivity and confusion or changes in behavior.

[5] It can also affect other parts of the body including skin, where it may appear as several fluid-filled nodules with dead tissue.

[4] These fungi are found globally in soil, decaying wood, pigeon droppings, and in the hollows of some species of trees.

[14] Diagnosis is by isolating Cryptococcus from a sample of affected tissue or direct observation of the fungus by using staining of body fluids.

Many of these findings are non-specific, but the presence of basal meningeal enhancement is significant as it is associated with the future development of cerebral infarct.

[4] When the brain is infected, symptoms include headache, fever, neck pain, nausea and vomiting, light sensitivity, confusion, or changes in behaviour.

[9] Symptom onset is often sudden when lungs are infected and gradual over several weeks when the central nervous system is affected.

Other conditions that pose an increased risk include certain malignancies (such as lymphoma), liver cirrhosis, organ transplants, and long-term corticosteroid therapy.

[22] In humans, C. neoformans chiefly infects the skin, lungs, and central nervous system (causing meningitis).

Males are more likely to develop the infection and a 2020 study showed that the sex bias may be due to a growth hormone, produced by C. neoformans called gibberellic acid (GA) that is upregulated by testosterone.

[24] Morphologic description of the lesions shows umbilicated papules, nodules, and violaceous plaques that can mimic other cutaneous diseases like molluscum contagiosum and Kaposi's sarcoma.

[25] Cryptococcus (both C. neoformans and C. gattii) plays a common role in pulmonary invasive mycosis seen in adults with HIV and other immunocompromised conditions.

The sensitivity of cultures and the Cryptococcal (CrAg) antigen with lateral flow device on serum are rarely positive in the absence of disseminated disease.

[32] CD4+ T cells have proven roles in the defense against Cryptococcus, but it can also contribute to clinical deterioration due its inflammatory response.

[33] Symptom onset is often subacute, progressively worsened over several weeks, and delays in diagnosis are associated with increased mortality.

India ink of the CSF is a traditional microscopic method of diagnosis,[35] although the sensitivity is poor in early infection, and may miss 15–20% of patients with culture-positive cryptococcal meningitis.

[36] Rapid diagnostic methods to detect cryptococcal antigen include latex agglutination testing, lateral flow immunochromatographic assay (LFA), or enzyme immunoassay (EIA).

[19] Cryptococcosis is a very subacute infection with a prolonged subclinical phase lasting weeks to months in persons with HIV/AIDS before the onset of symptomatic meningitis.

In Sub-Saharan Africa, the prevalence rate of detectable cryptococcal antigen in peripheral blood is often 4–12% in persons with CD4 counts lower than 100 cells/mcL.

[45] People living with AIDS often have a greater burden of disease and higher mortality (30–70% at 10 weeks), recommended therapy is with amphotericin B and flucytosine.

Adding flucytosine to amphotericin B is associated with earlier fungal clearance and increased survival, however, it is not readily available in many lower-income regions.

[34][46] Based on a systematic review, the most cost-effective induction treatment in resource-limited settings appears to be one week of amphotericin B coupled with high-dose fluconazole.

Regular (often daily) lumbar punctures to lower the intracranial pressure by draining CSF are associated with reduced mortality in those with cryptococcal meningitis (with or without HIV).

[19] Immune reconstitution inflammatory syndrome is possible in those with cryptococcal infection, especially those with concurrent HIV starting anti-retroviral therapy.

With anti-retroviral therapies for HIV, the CD4+ T-cell counts recover and the restored immune system mounts an exaggerated, hyperinflammatory response against cryptococcal infection in the body.

It is the most common deep fungal disease in cats, usually leading to chronic infection of the nose and sinuses, and skin ulcers.

Cryptococcosis is most common in dogs and cats but cattle, sheep, goats, horses, wild animals, and birds can also be infected.