Feline Cryptococcosis
Cryptococcosis is an infection caused by a microscopic fungus found in the environment. It is the most common systemic fungal infection in cats. Cats become infected by inhaling spores, particularly in areas contaminated by pigeon droppings...
What is it?
Cryptococcosis is an infection caused by a microscopic fungus found in the environment. It is the most common systemic fungal infection in cats.
Cats become infected by inhaling spores, particularly in areas contaminated by pigeon droppings or decomposing plant matter.
The infection most often affects the nose, with persistent nasal discharge, swelling on the nose bridge, and sometimes a pink mass visible in a nostril. It can also spread to the skin, eyes, and nervous system.
Commonly observed signs
These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.
Related signs — each one links to its page:
Chronic nasal discharge, often from one side initially, sometimes tinged with blood.
Sneezing and a stuffy nose sound, even when awake and at rest.
Firm swelling on the nose bridge, facial deformity, or a small pink or fleshy mass protruding from a nostril.
Swollen lymph nodes under the lower jaw.
Nodules under the skin that may ulcerate, particularly on the head.
Changes in vision, dilated pupils, or even blindness when the eyes are affected.
Decreased appetite and weight loss.
In nervous system involvement: behavioral changes, disorientation, seizures.
Signs develop over weeks—persistent nasal discharge that does not respond to routine treatments should raise suspicion of this infection.
When to consult without delay
This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.
Causes and risk factors
The infection is caused by fungi of the genus Cryptococcus, mainly Cryptococcus neoformans and Cryptococcus gattii.
These fungi live in the environment, particularly in accumulated pigeon droppings and decomposing plant matter.
The cat inhales spores, which first establish in the nose, then can spread to other organs.
Exposure to pigeon droppings and decomposing vegetation: balconies, roofs, attics, or yards where pigeons roost.
Cats that go outdoors; indoor cats can also be affected, as spores may enter the home.
FIV infection or feline leukaemia is sometimes associated with cryptococcosis, though this link is not constant.
Transmission
The cat becomes infected from the environment by inhaling spores, not through contact with another cat.
Direct transmission from a sick cat to another cat or to humans does not occur under normal living conditions.
Diagnosis and care
Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.
Your vet will examine your cat's nose, face, skin, lymph nodes, and eyes, paying particular attention to the back of the eye.
A blood test detecting a substance released by the fungus often confirms the diagnosis and distinguishes it from a nasal tumour.
Microscopic examination of a discharge, nodule, or sample from the nasal mass can show the fungus directly.
Head imaging, a biopsy, and testing for FIV and feline leukaemia often complete the investigation.
The same blood test is later used to monitor how well the treatment is working.
Treatment
Treatment relies on an antifungal medication, prescribed by your vet.
It is long-term, often lasting several months, and continues until tests—particularly the blood test—show the infection is under control.
A mass in the nose can be removed surgically to relieve your cat's symptoms, in addition to medication.
Severe forms, especially those affecting the nervous system, may require hospital care and more intensive treatment initially.
Do not stop treatment on your own once your cat seems better: the infection can return.
Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.
Prevention
Limit your cat's access to areas where pigeon droppings accumulate: balconies, roofs, attics, and stairwells.
Clean balconies and window ledges regularly when soiled, dampening the droppings before removal to avoid stirring up dust.
No vaccine is available.
Possible complications
Spread of infection to the eyes, resulting in vision loss.
Involvement of the nervous system, with behavioural changes and seizures.
Permanent facial deformity.
Relapse if treatment is stopped too early.
When to see a veterinarian
Your cat suddenly loses vision, has seizures, or shows behavioural changes: seek emergency care.
Your cat breathes with mouth open, or the gums or tongue are bluish: seek emergency care.
A lump appears on the nose, or a mass is visible in a nostril: consult within the next few days.
Nasal discharge continues for several weeks despite treatment.
Nodules appear under the skin.
Your cat is losing weight or eating less.
Prognosis
The outlook is generally good for forms limited to the nose, provided treatment is followed through to completion.
It is more guarded when the nervous system is affected.
Relapse is possible after stopping treatment: follow-up with blood testing is recommended.
Frequently asked questions
How to distinguish it from chronic rhinitis or a common cold?
Coryza begins suddenly, with watery eyes and fever. Chronic rhinitis often follows coryza, without nasal deformity. Cryptococcosis, on the other hand, produces a persistent discharge, sometimes with a bump on the top of the nose or a pink mass in one nostril. A specific blood test can provide a definitive answer.
Can I catch a disease from my cat?
Not directly: the fungus does not pass from a cat to a human in everyday life. However, you can become infected from the same source as the cat, for example from pigeon droppings. If your immune system is compromised, speak to your doctor about it.
Why does treatment take so long?
Fungi are slow to eliminate. Treatment often continues for several months until tests show that the infection is under control. Stopping too early risks relapse.
Are pigeons landing on your balcony: is my cat in danger?
The presence of pigeons does not necessarily lead to disease, but accumulated droppings are a known source of this fungus. Clean regularly by dampening the droppings before removing them, and limit the cat's access to heavily soiled areas.
References
Content reviewed by the TunisieVet editorial team · Updated 10 October 2026
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