Urticaria is a cutaneous (skin) hypersensitivity, characterised by small, raised patches of skin accompanied by itching. Rashes are rare in cats and usually associated with certain medications, flea bites, food allergies, chemicals (such as household chemicals), insect bites or stings and pollens, plants, food and flea collars.
Flea bites are one of the most common causes of rashes in cats.
The rash usually occurs within minutes of exposure to the allergen, and symptoms typically include:
- Small, raised wheals which can be localised with only a few or generalised with hundreds
- Facial swelling (not always)
If the exposure occurs over a period of time, the rash can become open and sore, or the skin can become hardened. Common areas include the feet, face, head and neck as well as the back, close to the base of the tail (usually causes by flea bite hypersensitivity) and flea treatments.
Hives are generally a nuisance but not particularly dangerous, if your cat scratches for a period of time, the skin can become damaged, making it more vulnerable to bacterial infection.
Anaphylaxis is a life-threatening severe reaction to an allergen that causes breathing difficulties, swelling around the eyes, mouth, and neck, intense itching and rash along with difficulty breathing, vomiting, pale gums and collapse. This is a medical emergency, death can quickly occur.
Find and remove the cause of the rash where possible. There may be some clues that include the location of the rash and if it is seasonal.
The veterinarian will ask the following:
- Your cat’s diet
- Is the cat on any medications (over the counter or prescription)
- Recent exposure to chemicals
- Any changes in the house, such as new carpets or change in cat litter etc
Eliminate the cause
- Diligent flea control not only on all household pets but the environment too.
- Change or stop medications where possible.
- Avoid the use of household chemicals, switch to natural products where possible
- Food elimination trial involves feeding a novel diet the cat has never eaten before (such as duck, or kangaroo). The cat will remain on this for several weeks, after which he will be re-introduced to his original food, to see if the allergy returns.
For a mild rash, Benadryl may be administered to block the effects of histamine.
A single injection of dexamethasone or prednisolone reduces symptoms by dampening the immune response.