Sporotrichosis in Cats

Sporotrichosis is a sporadic, chronic disease caused by the organism, Sporothrix schenckii that is found on timber, vegetation and in the soil. Sporotrichosis is a rare but potentially fatal fungal disease that cats and humans can contract, as the fungus easily enters the body through open sores on the skin. Sporotrichosis commonly appears as localized lesions of the nose, ears, and face of the feline, but can affect other portions of the body if left untreated. 

The symptoms a feline may experience depend on the type of Sporotrichosis the cat has contracted. 

Lymphocutaneous Sporotrichosis

• Small, firm skin bumps
• 1-3 cm in diameter
• Ulcerating lesions with discharge 
• Lesion are commonly seen on the pinnae (tips of the ears), nose and head. 
• Depression 
• Listlessness 
• Fever 

Cutaneous Sporotrichosis

• Swollen lymph glands
• Lymph disease 
• Dermal lesions
• Skin crusts with drainage 

Disseminated Sporotrichosis

• Fever
• Osteoarticular sporotrichosis: when the fungal infection spreads to the joints and bones.
• Sporotrichosis meningitis: when the fungal infection spreads to the nervous system and brain. 
• Anorexia 
• Cachexia (weight loss) 

Types

The fungal disease, sporotrichosis, can be grouped into three forms: Lymphocutaneous, cutaneous, disseminated. 

• Lymphocutaneous: the most common form of sporotrichosis, lymphocutaneous, is characterized by small, firm subcutaneous nodules. 
• Cutaneous: characterized by multicentric lesions that tend to remain localized. 
• Disseminated: a rare form of sporotrichosis, disseminated is potentially fatal and often results from neglect to lymphocutaneous or cutaneous stages of the fungal infection. 

A cat can become infected with sporotrichosis by coming into direct contact with the organism through wounds on the skin. As the fungus is found on various plants, a can become infected by penetrating foreign bodies (plant scratching the skin) or consuming one of these host plants. However, cats have a higher rate of contracting the infection if they are inflicted with a puncture wound, which gives the sporotrichosis organism a chance to enter the body. Cats that pose a risk for contracting the fungal disease include:

• Fighting male cats
• Multiple household cats 
• Immunosuppressive felines
• Felines around decaying organic debris 

Sporotrichosis in cats is difficult to diagnose because the symptoms associated with this disease mimic that of other cutaneous conditions. Therefore, your veterinarian will want to begin the diagnostic process by reviewing your feline’s medical history and asking you a series of questions about the feline’s recent activities. Recent cat fights, outdoor exposure, and contact with decomposing debris, such as garden compost, will be helpful in the veterinarian’s diagnosis. 

In order to eliminate other possible conditions causing dermal lesions, your veterinarian will want to perform a differential diagnosis. In order to pinpoint your cat’s condition to a sporotrichosis infection, the vet will first want to rule out the possibility of a drug eruption, parasite allergy, immune-mediated disease, lupus, squamous cell carcinoma, or a bacterial pyoderma. Therefore, blood work, a urinalysis, and skin cytology will be performed on the feline to further examine his/her condition. 

Sporotrichosis has a distinctive cytological feature compared to other lesion-causing skin diseases, which is often diagnosed via cytological evaluation of the skin sample. A sample can be obtained through a skin scraping, smear of a specimen swab, ulcerated skin impressions, or aspiration of the nodule or present abscess. 

Treating felines for fungal disease of the skin has proven to be somewhat of a challenge for veterinary practitioners. There is a variety of medical drug therapies a vet can use, however, many are not approved for animal use and have notable adverse effects. Talk to your veterinarian about possible adverse reactions caused by the drug chosen for treating your cat’s sporotrichosis and the appropriate way to monitor the feline at home. Therapeutic treatments can last anywhere from three weeks to a month and your vet may choose to continue well after the apparent clinical cure. Traditional drugs used to treat cats with Sporotrichosis include the following: 

• Sodium iodide 
• Potassium iodide 
• Ketoconazole 
• Itraconazole 
• Terbinafine 

Follow all veterinary directions and complete the duration of therapeutic treatment, even if the cat is no longer showing signs of illness. Sporotrichosis is commonly treated for at least a week past the point of apparent cure to ensure the fungal spores are removed entirely from the body, so make sure to complete the entire treatment plan. Adverse drug effects are common in cats receiving treatments for sporotrichosis, therefore, your veterinarian will ask for you to monitor the patient carefully at home. A feline showing any clinical signs of adverse effects will need to be taken to the vet clinic right away, as these adverse effects can be fatal.