Food allergies, irritation from grooming products, sensitivity to fleas or flea-treatment products, and ringworm are among the many possible causes of skin rash on a cat, states the ASPCA. Contact dermatitis because of allergy, contact with an irritant and reactive dermatitis from medications are other possible rash causes, notes petMD.
Some cats develop food allergies to certain foods, like beef, milk, poultry and corn, states the ASPCA. The cat's immune system treats those particular foods as foreign, which can cause itching and rashes. Fillers and colorings found in food also can become allergens.
Shampoo and other grooming products can irritate a cat's skin, explains the ASPCA. Fleas are another source of possible irritation of a cat's skin, or they may cause an allergic reaction. Symptoms of an allergic response to flea exposure include crusts and raised, red skin lesions. Additionally, certain flea collars can cause redness and skin irritation in cats that are sensitive to flea-treatment products.
Rash can result from ringworm, a highly contagious fungal infection, according to the ASPCA. Possible ringworm symptoms include inflammation, scaly patches on the skin and hair loss.
Contact dermatitis results from the cat coming into contact with something that has irritated her skin, states petMD. The rash typically is limited only to the area of contact with the irritant, such as poison ivy sap or road salt.