Particularly with S. brasiliensis infection, changes in the nasal lining and respiratory signs can be a central part of the disease, rather than just an uncommon additional finding.
When to see a vet urgently
Contact a vet promptly if your cat has:
- slow-healing nodules or wounds and has previously lived in an affected area;
- facial ulcers with nasal discharge, sneezing or eye symptoms;
- spreading skin lesions accompanied by loss of appetite or marked tiredness;
- difficulty breathing or a sudden deterioration in its general condition, which requires immediate emergency care.
Tell the practice about suspected sporotrichosis before arriving so that safe handling can be arranged. You can find a vet near you.
Overview
Sporothrix is a dimorphic fungus that lives in soil, plants and organic matter. Cats become infected when fungal spores enter broken skin through contact involving scratches, bites or splinters. The disease is usually more severe in cats than in other animals, and cats are considered an important source of human infection.
Dimorphic means that the fungus grows as filaments in the environment but takes a yeast-like form in animal tissues. An infected wound may contain large numbers of fungal cells. Simply touching wound discharge can be dangerous, and human infection does not always require a noticeable bite or scratch.
The infection may remain localised or spread through lymphatic vessels to nearby lymph nodes. These vessels carry tissue fluid, and new nodules may develop along their course. The number of skin lesions alone does not show whether internal organs are also infected. Initially, a cat may otherwise appear well.
Causes
- Contact with contaminated soil, hay or plants.
- Scratches and bites from infected cats.
- Spores entering the skin through injuries.
- Less commonly, inhalation of spores.
Cat-to-cat and cat-to-human transmission are central to S. brasiliensis infection. It is therefore misleading to think of every Sporothrix species simply as a cause of wound infection acquired from soil. Protection must also take nasal and oral secretions into account, especially if the cat has respiratory signs.
The risk of infection is assessed from travel and contact history. As well as the country of origin, tell your vet about previous places of residence, outdoor access and contact with sick cats. The cat's current country of residence alone does not describe its previous exposure. Equally, ordinary contact with a garden does not in itself indicate sporotrichosis.
Risk factors
- Cats with outdoor access.
- Cats living in rural areas.
- Cats with skin injuries and weakened immunity.
- Crowded conditions, such as rescue shelters and breeding establishments.
- Cats brought from areas where the disease occurs, such as Brazil.
The disease is not confined to rural areas: cat-associated epidemics also occur in cities. Unneutered outdoor males make up a large proportion of affected cats in endemic areas, but females and indoor cats can also become ill. These observations relate particularly to the epidemic areas studied and do not establish the risk for cats elsewhere.
Weakened immunity is not necessary for infection. Even an apparently healthy cat that tests negative for FIV or FeLV can develop severe disease. Virus status therefore cannot rule out sporotrichosis. Cases have also been described in Europe, so country of origin helps the assessment but cannot replace investigations.
Typical symptoms
- Firm nodules under the skin that burst and become ulcers.
- Clear or pus-like discharge.
- Lesions most often on the face, ears, paws and tail.
- Enlarged regional lymph nodes.
- A chronic course with slow-healing wounds.
- Damage to the lungs, bones and eyes in generalised disease.
A lesion may resemble an ordinary bite abscess or tumour. A nodule may ulcerate, bleed and become crusted. A photograph or the appearance of a wound alone cannot distinguish sporotrichosis from another deep fungal infection, a bacterial infection or a skin tumour.
Damage to the nasal lining may cause sneezing and nasal discharge. Respiratory signs may also appear before visible skin lesions. Normal-looking skin therefore cannot by itself rule out the disease in an exposed cat. Changes in or around an eye need examination; do not wipe away discharge with bare hands.
Complications and consequences
- Chronic ulcers and draining tracts.
- Generalised fungal infection, which is uncommon but life-threatening.
- Lengthy, difficult treatment.
- Human infection through contact with the cat, especially scratches and bites.
Prolonged disease can make eating difficult and impair nutritional status. Fever or weight loss alone does not show that the infection has spread to internal organs, but increases the need to assess the whole cat. Prognosis depends on the extent of the lesions, involvement of the respiratory tract or internal organs, and treatment success.
Interrupting treatment can cause a relapse even when the wounds appear to have healed. Skin closing over therefore does not mean that medication or protective measures can stop. Sustained treatment and infection prevention are planned so that you can carry them out.
Diagnosis at the vet
- Cytological examination of impression samples from ulcers to look for yeast-like fungal cells.
- Fungal culture for Sporothrix.
- PCR testing.
- A skin biopsy.
- Ruling out other causes of chronic ulcers, such as ringworm, bacterial infections and tumours.
Cytology can quickly raise a strong suspicion, but a negative sample does not rule out infection. There may be few fungal cells in the sample, or previous treatment may have reduced their numbers. Tell your vet about all medicines and creams used before sampling.
Under a microscope, yeast-like cells may resemble other fungi, so tissue examination or PCR may be used for confirmation. PCR looks for the organism's genetic material. The need for culture is decided with the diagnostic laboratory: handling Sporothrix cultures requires appropriate safety arrangements. Do not collect samples or grow cultures at home.
Blood tests assess general health and treatment safety, but inflammatory changes alone do not identify sporotrichosis. Depending on the symptoms, imaging of the lungs or another area may be needed. A wound that does not respond to antibiotics is a reason to reassess the diagnosis, rather than to try successive medicines at home.
Treatment and follow-up
Treatment relies on systemic antifungal medication prescribed by a vet. Wound cleaning or an antibiotic alone will not eliminate the fungal infection. A concurrent bacterial infection can be treated separately. The choice of medicine depends on the extent of the symptoms, other illnesses and any previous adverse effects.
Some antifungals can affect the liver or cause loss of appetite and vomiting. Liver blood tests may be needed before and during treatment. Report jaundice, worsening appetite and new symptoms. The practice decides whether to continue or change medication; do not adjust the dose yourself.
Medication may be supplemented with a local procedure if necessary. The decision depends on the location of the lesion and its response to treatment. Do not attempt surgery, heating or strong cleaning products on facial lesions yourself. A corticosteroid preparation can worsen a fungal infection, so tell your vet about all other medicines being used.
Safe care at home
Keep the sick cat indoors, separate from other animals, as the practice advises. Provide separate food and water bowls, a litter tray and washable resting surfaces. Do not let it lick people's wounds or faces. Children and people with weakened immunity should not handle the sick cat.
Use the protective equipment you have been advised to wear, and avoid bites, scratches and splashes of discharge into the eyes. Gloves alone do not protect against every exposure. Wash your hands with soap after removing them. If you cannot give medication or care for wounds safely, request a revised plan before handling the cat again.
Agree separately on how to clean surfaces, the carrier, fabrics and discharge. Remove visible dirt before disinfecting. Follow instructions when choosing the product, method and required contact time; do not mix chemicals. Also follow the product's instructions for safe rinsing and drying before returning the cat to the area.
Record changes in the wounds, the amount eaten, general condition and any difficulties giving medication. A reduced appetite calls for assessment of pain, nausea and nutritional support. Do not force food into the cat's mouth. If the cat dies, agree with your vet how the body should be handled; do not bury it in soil because of the risk of environmental contamination.
If a person is exposed
Wash a scratch or bite immediately with soap and water and seek medical assessment. Explain the cat's suspected or confirmed sporotrichosis and where it came from. A skin nodule, wound or eye symptom developing after exposure also needs examination. Human investigations and treatment are arranged by healthcare professionals; do not take the cat's medicine yourself.
Prevention
- Limit your cat's contact with soil, hay and compost.
- Prevent fights and outdoor injuries.
- Wear gloves when caring for your cat's wounds.
- Maintain hygiene in rescue shelters and breeding establishments.
- Tell family members that the disease can spread to people.
Reducing transmission starts as soon as the disease is suspected. Simply covering wounds does not replace separation and safe handling. Keep the cat's import and medical history for future investigations. Routine vaccinations do not prevent sporotrichosis, and no preventive vaccine is available against it.
Important for cat owners
Sporotrichosis is an uncommon but serious disease in cats that also poses a danger to people. Remember that every chronic ulcer or non-healing nodule is a reason to take your cat to a vet, particularly if it has been brought from another country. Once the diagnosis is confirmed, treatment is lengthy and the cat must be handled carefully to prevent infection spreading to people.
This article provides general information and does not replace veterinary care. If you notice signs of illness in your cat, contact a vet.
Frequently asked questions
Can sporotrichosis spread without a bite?
Yes. Wound discharge and other close contact can also transmit infection. Follow the practice's protective advice and avoid getting discharge on your skin, eyes or other mucous membranes.
Does a negative cytology sample rule out the disease?
No. There may be few fungal cells in the sample. If the symptoms and exposure history fit the disease, your vet will choose the necessary confirmatory tests.
Can treatment stop when the wounds have closed?
Only if your vet decides it can. Treatment is often needed beyond visible healing, and stopping too early can cause a relapse. Ending separation and protective measures must also be agreed separately.
This article is for general information only and is not a guide to treatment. If you notice the first signs of illness, contact your vet.
Paw4care editorial team
Sources
- Guideline for Sporotrichosis, European Advisory Board on Cat Diseases, accessed 2026-11-05.
- Sporotrichosis in Animals, Merck Veterinary Manual, accessed 2026-11-05.
- Guideline for the management of feline sporotrichosis caused by Sporothrix brasiliensis and literature revision, Brazilian Journal of Microbiology, accessed 2026-11-05.
- Sporotrichosis in Domestic Cat and Zoonotic Transmission, Emerging Infectious Diseases, accessed 2026-11-05.
- Esporotricose Humana, Ministério da Saúde do Brasil, accessed 2026-11-05.
- Fungal Infections in Cats, Merck Veterinary Manual, accessed 2026-11-05.
- 2022 ISFM Consensus Guidelines on Management of the Inappetent Hospitalised Cat, Journal of Feline Medicine and Surgery, accessed 2026-11-05.
- About Cleaning and Disinfecting Pet Supplies, CDC, accessed 2026-11-05.