Sporotrichosis in dogs

Sporotrichosis in dogs

Sporotrichosis is a fungal disease caused by a fungi named Sporothrix schenckii. Sporotrichosis is more common in horses and cats, but it can infect dogs and humans too. When a dog gets infected by Sporotrichosis, it usually manifests in the form of nodular skin lesions located on the head and trunk of the dog. Sporotrichosis is a slowly progressing dog disease and it can take from one to twelve week for the first symptoms to appear when the dog has been infected. The average time period between initial exposure and noticeable symptoms are normally around three weeks.

Different forms of Sporotrichosis

Cutaneous Sporotrichosis, also known as Skin Sporotrichosis
Cutaneous Sporotrichosis is the most commonly occurring form of Sporotrichosis, in dogs as well as in other animals. The most prominent symptom of Cutaneous Sporotrichosis are nodular lesions or bumps that appear on the skin. They symptoms start where the fungi first gained entrance to the body and can then spread along lymph nodes and vessels. To begin with, the lesions are small and painless and the dog is seldom very bothered by them. The colour varies from pink to purple. If you do not bring your dog to the vet, the lesions and bumps can grow bigger and bigger until they look like boils. More and more lesions can appear and eventually the dog will start suffering form a chronic ulcer. 

When cats are infected, they can develop a type of cutaneous Sporotrichosis that is much more severe than the one normally seen in dogs.

Pulmonary Sporotrichosis
This form of Sporotrichosis can develop when the dogs has inhaled Sporothrix schenckii spores. The dog can start coughing and the lymph nodes can swell up. The coughing is often productive, i.e. the dog coughs up mucus. Fibrosis, and nodules and cavitations of the lungs, are other symptoms of Pulmonary Sporotrichosis in dogs. A dog with pulmonary Sporotrichosis is more prone to develop other lung problems, including pneumonia.

Disseminated Sporotrichosis
If a Sporotrichosis infection spreads from its primary site to other parts of the body, the condition is called disseminated Sporotrichosis. This is rare in dogs, and also very serious. Disseminated Sporotrichosis can for instance affect the bones and joints of the dog, and will then be called osteoarticular Sporotrichosis. It can also infect the dog's brain and central nervous system, so called Sporotrichosis meningitis. Common symptoms of disseminated Sporotrichosis are bony lesions, loss of appetite and weight loss.  

Transmission of Sporotrichosis

As mentioned above, Sporotrichosis is caused by the Sporothrix schenckii fungi. This fungus is naturally found in soil, plants, hay, peat moss and similar. If the dog's skin is perfectly intact, the fungi pose no risk, but if the dog has a small cut or abrasion the fungi can enter and cause Sporotrichosis. You should also keep cats with cutaneous Sporotrichosis away from other animals, dogs included, since such cats give off a lot of spores from their wounds.

Pulmonary Sporotrichosis is the result of inhaling Sporothrix schenckii spores.

Humans catching Sporotrichosis from dogs are extremely rare, but cats with the severe form of cutaneous Sporotrichosis have infected quite a few veterinarians. When humans come down with Sporotrichosis, it is usually the result of gardeners and agricultural workers coming in contact with soil, hay, peat moss or similar. Since roses can spread the disease – especially to hands and arms cut by rose thorns -  Sporotrichosis is one of a number of diseases known as rose-thorn disease or rose-gardeners' disease.

Sporotrichosis treatment for dogs

How to treat your dog for Sporotrichosis will depend on where the disease is located and how severe it has become. If your dog suffers from Cutaneous Sporotrichosis, the vet can give it oral droplets of saturated potassium iodide. This type of Sporotrichosis treatment normally has to be carried out for 3-6 months, so it is a good idea to ask your vet about how to perform it at home. Another treatment choice is intraconazole, an anti-fungal drug. If your dog can not tolerate Intraconazole (Sporanox), fluconazole can be used.

A more potent drug for Sporotrichosis is Amphotericin B delivered intravenously. Due to the common occurrence of Amphotericin B side effects, it is usually reserved for dogs whit more severe cases of Sporotrichosis. Amphotericin B can for instance lead to nausea, vomiting and fever. When a dog suffers from sporotrichosis meningitis, a powerful combination of Amphotericin B and 5-fluorocytosine can be required.

When Sporotrichosis leads to bone infections and cavitatory nodules in the lungs of the dog, surgery can be necessary.

Fungal Infections in dogs: (click for more info)
Blastomycosis in dogs
Cryptococcosis in dogs
Histoplasmosis in dogs
Phycomycosis in dogs
Pythiosis in dogs
Ringworm in dogs
Sporotrichosis in dogs