Itchy skin and rashes are symptoms of allergic skin conditions. Food allergies frequently result in a rash and irritated skin. Severe allergic responses can result in hives, rashes, and swellings across the body. If you feel your cat is suffering a severe allergic reaction, contact your veterinarian immediately—this is an emergency. Other common causes of skin problems in cats include: Parasites such as fleas or ticks that bite cats often develop skin diseases as a side effect of being bitten by another animal. These parasites spread disease causing bacteria or viruses into the cat's blood when they bite them. If your cat has not been treated with heartworm prevention, have him checked by a vet before starting treatment for other skin disorders. Skin problems can also be caused by food allergies or dietary changes. If you start seeing signs of skin irritation such as dry skin or scabs, take your cat to the vet right away so that any underlying problems can be treated.