Domestic cat scratch themselves for the same reason that we scratch ourselves: to relieve an itch. Before I explain some reasons for itchiness in domestic cats there are two aspects which are noteworthy, (1) cats sometime scratch themselves far too much because they don’t rationalise the fact that they are hurting themselves with their claws which (2) leads to my belief that cats have difficulty thinking rationally and when they scratch themselves as it is entirely instinctive to the point of self-mutilation. The problem is that when a cat scratches herself she does so with her claws whereas humans do it with their nails. The latter is much more blunt than the former.
Cats can develop an itch for a whole range of reasons and I will briefly mention them but you need to see a veterinarian to deal with this properly. It is shocking to see pictures of cats on the internet who have self-mutilated to the point of serious injury because of a persistent itch which their owner has simply ignored. Quite awful to look at.
- Itchy cats: Don’t give anti-flea treatment first
- Itchy Kitties: Cats that Self-Groom Excessively
- Cat losing hair on back of ears?
Fleas are a major potential issue for all domestic cats and they can itch like hell. Also cats can develop an allergy to the flea bite which makes matters worse. The first thing to check is fleas if your cat is scratching. There are many pages on this website about cat fleas and all over the net. The Internet is covered in pages on cat fleas just like some cats are covered with this bloody parasite.
Other parasites can cause cats to scratch including mites; head mange caused by the head mite, walking dandruff caused by a large reddish mite which lives on the skin causing itching and a large amount of dry, scaly material that looks like dandruff. Another ghastly mite, called the harvest mites a.k.a. chiggers causes severe irritation and the formation of red draining sores with overlying scabs: quite ghastly. Lice can also infest domestic cats. They are not common. They can bite the cat while feeding on skin scales. They cause itching and constant irritation.
The dreaded allergies are another cause of itchiness in domestic cats. There are numerous causes of allergies which is a cat’s immune system overreacting to a food, something inhaled or something in the cat’s environment. You need to look for the allergen (the cause) which is tricky and you will need a veterinarian to do it. The flea bite allergy mentioned above falls into this category. It causes severe itching resulting in intense scratching. The result of this you will see on the Internet causing these horrible self-mutilated wounds. To this bracket we have to add irritant contact, allergic contact dermatitis and atopic dermatitis (inhalant allergy).
Seborrhoea can cause itching in a cat. There is a dry and scaly form and an oily scaly form causing an unpleasant odour as well as a greasy feeling.
Immune-related skin problems
Immune-related skin problems is an autoimmune skin condition in cats causing itchiness. It can also cause lameness if the feet are involved. Cats are ill with a fever and loss of appetite.
Young to middle aged cats might suffer from an itchy skin condition called eosinophilic plaque.
Although domestic cats barely scratch it, an irritation of the eyelids can cause itching. Remaining with the eyes, ‘irritated eyelids’ is also called blepharitis. The cause is often an injury occuring during cat fights. Infection can set in leading to itching and scratching. This makes things worse. Head mange mites can also cause blepharitis.
Conjunctivitis causes itching. This is a bacterial infection of the eye, specifically an inflammation of the membrane covering the back of the eyelids and the surface of the eyeball up to the cornea. Cats won’t scratch the area obviously but they will paw at the eye to relieve itching.
Regarding the anus and rectum, signs of a rectal disease includes scooting which is a sign of anal itching. It can be caused by flea bites, tapeworms, roundworms, anal sac disease and inflammation of the anus.
We have to mention the ears and ear mites. Ear mites are incredibly irritating causing a huge amount of itchiness resulting in ear scratching and headshaking. This can result in injury to the inside of the ears leading to a secondary infection which in turn leads to an abscess. If your cat is scratching their ears unnaturally i.e. for too long a time then see a veterinarian. Cats do scratch their ears from time to time because of day-to-day itchiness which is nothing to worry about but you’ll have to distinguish between that and itchiness caused by ear mites. Any doubts? See a veterinarian, please.
Remaining with the ears, ear allergies cause itching and skin redness without drainage. This form of allergy can be caused by food and inhaled allergens. Finally, sunburn can cause itchiness resulting in scratching which makes it worse by causing an open sore ulcer. This can lead to squamous cell skin cancer.
It should be mentioned that domestic cats also relieve itchiness with their tongues because their tongues can scratch their skin due to the keratin spines attached to the top surface of the tongue. When cats relieve an itch with their tongue they gradually remove the hair from their bodies so you will see bold spots. Cats cannot get to places with their tongue that they can with their hind claws for obvious reasons.
See a vet
The list is not completely comprehensive but is quite long as you can see. It is a complicated area requiring veterinary intervention. It’s a question of observing your cat and seeing whether they are scratching too much and causing themselves injury. If they are urgent action is required.
Source: myself and Cat Owner’s Home Veterinary Handbook (many pages).