Allergies are the result of a misguided immune system. Even though some substances are perfectly safe, if your body is overly sensitive, it may misidentify certain allergens as dangerous and react by fighting them off. The most common allergens produced by cats are the proteins found in the cat's saliva and sebaceous glands, along with the dander, or skin flakes, that they shed. The battle against allergens can be manifested in a number of ways.
About Hives and Other Allergy Symptoms Caused by Cat Dander
The pruritic (itchy) cat – when it is not fleas | International Cat Care
Overview Skin problems are among the most common troubles for dogs and cats. They can be caused by a variety of diseases, one of the most common being allergies. Allergies that affect the skin are grouped together under the term allergic dermatitis. As with people, our pets can suffer allergies related to the food they eat and the environment they live in. Additionally, they can have an allergic reaction to the bites of fleas and other parasites.
The pruritic (itchy) cat – when it is not fleas
Cat skin rashes can be caused by exposure to an allergen in the environment or allergic reactions to the current pet food. Common symptoms of skin allergies include excessive scratching, rubbing or chewing at the skin; hair loss; or skin rashes. A rash could also be an indication that your cat has fleas or mites, according to the John and Caroline Bower, authors of "The Cat Owner's Problems Solver. Wash all bedding. The allergen may be located where your cat sleeps, according to Bower.
In cats they are sometimes even referred to as miliary dermatitis. Hot spots can happen to any cat, but cats with fleas or a history of allergies are more prone to developing a hot spot. Cats with long, thick coats may also be more prone to developing a hot spot. When a cat comes into my hospital showing hair loss or hair being matted to the skin, along with the skin being very red from inflammation and fluid oozing from the skin infection, I suspect a hot spot.