Sporotrichosis is a long-lasting fungal infection of the skin. It causes lumps and open, draining sores that do not heal. Cats get it more than other animals, and an infected cat can pass it to people.
Sores that do not heal and keep draining need a vet. In most pets the disease shows up as skin lumps that later break open and drain [1]. Do not treat these sores at home.
Protect yourself. Sporotrichosis is a zoonosis, which means it can pass from animals to people, and cats pass it on far more easily than dogs [1]. If your cat might have it, handle it as little as possible and ask your vet what precautions to take. If an infected or suspect cat scratches or bites you, see your own doctor.
What causes sporotrichosis
The infection is caused by fungi of the Sporothrix group. They live in soil and on plants, and do best in damp soil full of rotting plant matter. They have been found on rose thorns, moss, tree bark and old mine timbers [1]. The disease occurs in warm and temperate parts of the world, above all in the Americas, and is uncommon in Europe [1].
Most infections start when the fungus gets into a wound, for example from a thorn, a splinter, soil or plant material, or from the bite or scratch of a sick animal. Breathing in fungal spores is a less common route [1].
Sporotrichosis in cats
Cats are very prone to sporotrichosis [1]. In Latin America, where the disease is common, a recent review found that pet cats are the main way the infection reaches people [4].
Signs in cats
- Lumps and sores: most cats get several lumps, open sores and crusts, because they spread the fungus around their own body while grooming [1].
- Range: in a large outbreak of 347 cats in Rio de Janeiro, the skin changes ran from small bumps to wide areas of dead tissue [2]. In severe cases the dead skin can leave muscle and bone exposed [1].
- Breathing signs: in the same outbreak, sneezing and other breathing signs were the most common problem outside the skin [2].
- Spread through the body: the form that spreads to inner organs is rare, but it is seen more in cats than in other pets [1].
Why cats spread it to people
The sores of an infected cat usually hold large numbers of the fungus, much more than a dog’s sores do. That is the main reason cats pass the disease to people more easily [1]. A cat can also pass it on through bites and scratches [1].
Sporotrichosis in dogs
Dogs get it less often. In some dogs it stays in the skin; in others firm lumps form where the fungus got in and then spread along the lymph vessels, often with swollen lymph nodes nearby [1]. In a study of 44 dogs in Rio de Janeiro, the most common finding was one open sore on the nose, and breathing signs were the most common problem outside the skin [3].
When the infection spreads
Rarely, the fungus travels through the blood and lymph to inner organs. It can reach the bones, lungs, liver, spleen, kidneys, testes, gut and brain, and the skin then shows sores in many places [1]. This is one more reason to see a vet early.
How vets diagnose it
Vets usually take samples from the sores. Looking at cells under a microscope (cytology) often finds the fungus in cats, because their sores hold so much of it, but it is hard to find this way in dogs [1]. Growing the fungus in the lab (culture) is the most reliable test, but it is slow and the result can take weeks [1]. Special stains, PCR tests and, for cats, a blood test may also help, and more than one test may be needed [1].
Treatment
Treatment is long. It is usually continued for some time after the sores have healed [1]. Your vet will choose the medicine and decide how long to give it.
At home, as directed by a vet:
- give the medicine exactly as prescribed, and do not stop early on your own, even if the sores look healed;
- follow your vet’s advice on handling and hygiene;
- keep the pet indoors and away from other animals if your vet advises it;
- go back for every recheck.
Keeping people safe
The people most at risk are those who handle and treat a sick animal, such as vets, their staff and the owner who gives the care [1]. The handbook advises wearing disposable gloves when handling a cat with draining sores and washing hands and arms with soap afterwards [1]. Ask your vet what precautions you and everyone in your home should take while your pet is ill.
If you are scratched or bitten by a cat that has, or may have, sporotrichosis, or if you get a sore that does not heal, see your own doctor and tell them about the cat.
Outlook
Outcomes vary between studies:
- A veterinary dermatology handbook reports that more than 70% of cats and about 80% of dogs can be cured when they get suitable treatment. It notes that sores on a cat’s nose are hard to treat, that cats with breathing signs died about twice as often, and that the disease can come back after treatment ends [1].
- In the Rio de Janeiro outbreak of 347 cats, 124 cats died and 118 were lost to follow-up. Treatment was given to 266 cats, and 68 of them were cured. The authors felt that cats can do well when treatment is given steadily over a long time [2].
- In the study of 44 dogs, the authors felt that many dogs did well with treatment, and that in a few dogs the sores cleared up without it [3].
These are figures and statements about groups of animals in particular studies. They do not prove that a treatment caused an outcome, and they cannot predict how one animal will do. Your vet can explain what this means for your pet.
When to see your vet
See your vet if your cat or dog has:
- a sore that does not heal, or keeps draining [1];
- lumps or sores on the nose, face or ears [1][3];
- new lumps along a leg or the body near an old wound [1];
- sneezing or breathing signs together with skin sores [2][3];
- fever, low energy or poor appetite.
See your own doctor if you are scratched or bitten by a sick cat, or get a sore that does not heal.
FAQ
Can I catch sporotrichosis from my cat?
Yes. Cats are the pets most likely to pass it to people [1][4]. Ask your vet about precautions, and see your own doctor if you are scratched, bitten or get a sore that does not heal.
Can I catch it from my dog?
It is possible but much less likely than from a cat, because dogs’ sores hold far fewer fungi [1]. Follow your vet’s guidance when handling a sick dog.
How long does treatment take?
It is long and continues after the sores look healed [1]. Your vet will tell you when it is safe to stop.
Can sporotrichosis be cured?
It varies, and no one can promise it. See Outlook above, and ask your vet about your pet.
Is it the same as ringworm?
No. Both are fungal skin infections that can pass to people, but they are caused by different fungi. See ringworm in dogs and cats.
The bottom line
Sporotrichosis is a fungal infection that causes lumps and non-healing, draining sores, most often on a cat’s head. Cats can pass it to people, so handle a sick cat carefully, follow your vet’s advice, and see your own doctor if you are scratched or bitten. Treatment is long, and it must not be stopped early.
This article is for general information only and does not replace advice from your veterinarian or your doctor. If your pet has a sore that will not heal, contact your vet.
Sources
- Torres SMF. 4.8 Cutaneous and Subcutaneous Mycosis: Sporotrichosis, Small Animals. Small and Large Animal Dermatology Handbook, Vol. 1. University of Minnesota, 2025. CC BY 4.0. https://open.lib.umn.edu/animaldermatology/chapter/subcutaneous-mycosis-sporotrichosis-small-and-large-animals/
- Schubach TM, Schubach A, Okamoto T, et al. Evaluation of an epidemic of sporotrichosis in cats: 347 cases (1998-2001). J Am Vet Med Assoc. 2004;224(10):1623-1629. https://pubmed.ncbi.nlm.nih.gov/15154732/
- Schubach TM, Schubach A, Okamoto T, et al. Canine sporotrichosis in Rio de Janeiro, Brazil: clinical presentation, laboratory diagnosis and therapeutic response in 44 cases (1998-2003). Med Mycol. 2006;44(1):87-92. https://pubmed.ncbi.nlm.nih.gov/16805098/
- Santos MT, Nascimento LFJ, Barbosa AAT, et al. The rising incidence of feline and cat-transmitted sporotrichosis in Latin America. Zoonoses Public Health. 2024;71(6):609-619. https://pubmed.ncbi.nlm.nih.gov/39044549/