Could My Cat Have a Fungal Respiratory Infection (Cryptococcosis)?

Cryptococcosis is a fungal infection that commonly affects a cat's nose and lungs. Learn signs, tests, when it's urgent, and treatment options.

What is cryptococcosis in cats?

Cryptococcosis is a fungal infection caused by Cryptococcus species (most commonly C. neoformans and C. gattii). In cats the fungus most often enters through the nose and sinuses and can cause local respiratory disease, nasal discharge, facial swelling, and, in some cases, spread to the central nervous system, eyes, skin, or lungs. Although cryptococcosis is less common than viral or bacterial respiratory disease in cats, it is an important consideration because it requires specific antifungal treatment and can progress without veterinary care (Merck Veterinary Manual).

How do cats get infected?

• The fungus lives in the environment (soil, bird droppings, decaying wood, and certain trees). Cats inhale yeast spores or desiccated cells.
• Outdoor cats or those in areas where C. gattii is endemic (certain regions of North America, Australia, and other areas) are at higher risk.
• Not all exposed cats develop disease—immunity and dose of exposure influence whether infection occurs.

Common signs and symptoms

Signs can be subtle at first and depend on the site of infection. Common respiratory and related signs include:

• Persistent nasal discharge (often clear but can be bloody or mucopurulent)
• Sneezing and snorting
• Nasal obstruction or noisy breathing
• Facial swelling or deformity over the nose or sinuses
• Ulcerative lesions on the nose or head
• Lethargy, decreased appetite, and weight loss
• Coughing or labored breathing (if lungs involved)
• Eye problems (uveitis, retinal detachment, vision changes) if infection spreads
• Neurologic signs (head tilt, seizures, ataxia) when the central nervous system is affected

When to See a Vet Immediately

Seek veterinary attention right away if your cat has any of the following:

• Severe difficulty breathing, open-mouth breathing, or bluish gums/lips
• Sudden collapse, seizures, loss of consciousness, or severe neurologic signs
• Persistent large amounts of bloody nasal discharge or rapidly increasing facial swelling
• Rapidly worsening lethargy, refusal to eat, or signs of severe pain

Red Flags - Seek Emergency Care

• Respiratory distress (gasping, panting, open-mouth breathing in a cat)
• Blue or pale mucous membranes (gums)
• Collapse, seizures, sudden blindness, or marked disorientation
• Continuous heavy bleeding from the nose

How is cryptococcosis diagnosed?

Diagnosis requires veterinary tests—owners should not attempt to diagnose at home. Common tests include:

• Physical exam with attention to nasal passages, eyes, skin, and neurologic status
• Cytology (microscopic exam) of nasal discharge, aspirates, or skin lesions to look for the yeast with a characteristic capsule
• Fungal antigen test (cryptococcal antigen latex agglutination test): a blood or cerebrospinal fluid test that is sensitive and useful for diagnosis and monitoring treatment response
• Culture of fungus from affected tissues (may take time)
• Imaging: skull or chest X-rays, CT, or MRI if deeper or neurologic disease is suspected
• Additional labwork: CBC and chemistry to assess overall health and rule out other issues

Differential diagnosis (common causes ranked by likelihood)

When a cat has chronic nasal or respiratory signs, consider these causes (ranked roughly by how commonly they present in general practice):

Your veterinarian will use history, physical exam findings, and targeted tests to narrow this list. Cryptococcosis moves higher on the list when there is chronic progressive disease, facial swelling, unexplained skin lesions, or neurologic/ocular signs.

Treatment options

Treatment is medical and must be prescribed and monitored by a veterinarian. Typical approaches:

• Azole antifungals: Itraconazole and fluconazole are commonly used oral medications. Treatment is prolonged (months) and continued until antigen testing shows resolution. Itraconazole is often preferred for nasal and localized disease; fluconazole penetrates the central nervous system better and is sometimes chosen when brain involvement is suspected.
• Amphotericin B: Reserved for severe, disseminated, or refractory infections. Given IV and can require hospitalization and close monitoring due to kidney toxicity.
• Supportive care: Fluid therapy, nutritional support, treatment of secondary bacterial infections, and anti-inflammatory or analgesic medications as needed.
• Surgery: Rarely, surgical debridement is used for localized nasal masses or to relieve severe obstruction, but most cases are managed medically.

Never attempt antifungal treatment or dosing at home without veterinary prescription—these drugs can cause serious side effects and require monitoring.

Home care while your cat is being evaluated or treated

• Keep your cat calm and indoors to reduce stress and further environmental exposure.
• Maintain easy access to food, water, and a comfortable litter area.
• Use a humidifier or steamy bathroom (briefly) if your cat is congested—this can help loosen secretions, but do not force or attempt nasal irrigation without veterinary guidance.
• Protect your cat from additional respiratory pathogens (isolate from sick pets if possible).
• Follow all medication instructions, attend recheck appointments, and report side effects such as anorexia, vomiting, jaundice, or changes in behavior.

Prognosis

Prognosis varies by the severity and extent of disease and how quickly treatment begins. Localized nasal disease treated promptly with appropriate antifungals often has a good prognosis. Disseminated disease or central nervous system involvement carries a more guarded prognosis and may require aggressive therapy. Early diagnosis and adherence to long-term treatment significantly improve the chance of a good outcome (Merck Veterinary Manual).

Prevention and risk reduction

• Reduce outdoor exposure in high-risk areas if possible.
• Avoid environments with heavy accumulations of bird droppings and decaying organic material.
• Keep indoor cats indoors where practical to limit environmental exposure.
• Promptly address chronic nasal or ocular signs with your veterinarian—earlier diagnosis reduces complications.

Key takeaways

• Cryptococcosis is a fungal infection that commonly affects the nose and respiratory tract of cats and can spread to eyes and the brain.
• Signs include chronic nasal discharge, facial swelling, sneezing, and sometimes neurologic or ocular signs.
• Diagnosis requires veterinary testing (antigen testing, cytology, imaging). Do not attempt to diagnose or treat at home.
• Treatment is long-term antifungal therapy supervised by a veterinarian; prognosis is better with early diagnosis.
• Seek immediate veterinary care for breathing difficulty, collapse, seizures, severe bleeding, or sudden blindness.

References

• Merck Veterinary Manual: Cryptococcosis in animals. https://www.merckvetmanual.com/generalized-conditions/cryptococcosis/cryptococcosis-in-animals
• Veterinary Emergency and Critical Care Society (VECCS): emergency care guidance and resources. https://veccs.org/

Frequently Asked Questions