Does Kitty have bald spots on his back or legs? Unlike dogs, who tend to scratch at itches, felines lick them. Since they can reach their backs, that's often where you'll first observe hair loss. There are a number of reasons your cat's losing the fur off his back.
Allergies
A common cause of hair loss is skin allergies. Kitty can react to many of the same allergens as you do, like pollen, mold or dust. He can have a reaction to a household cleaner that he's rubbed against, whether he's ingested it or not. His vet can perform skin and blood tests to determine what's aggravating him, and prescribe antihistamines and steroids to relieve itching. If the vet suspects a food allergy, an elimination diet may be in order. Your cat will be put on a special diet whereby different proteins and carbs are slowly added to his diet to determine what's causing the reaction.
Fleas
Fleas can be a source of discomfort for your kitty. Aside from the annoyance of crawling on his skin and sucking his blood, they can cause Kitty to lose his hair. If he develops red, itchy bumps and bald spots, he's probably allergic to the fleas' saliva. Keeping Kitty on a year-round topical flea preventative can prevent him become infested with the little bugs in the first place. It's also a good idea to keep him indoors, where he's less likely to come in contact with fleas.
Ringworm
Ringworm isn't actually a worm; it's a fungus. It lives on the surface of the skin and causes his hair to die and break. When this happens, a red, scaly ring will appear on the hairless skin. Ringworm is seen most commonly on his back, ears, head and paws. It's highly contagious, not only to other cats in the home but to you, too.
Your cat's vet will prescribe antifungal pills or a topical lotion, and you'll have to keep him isolated at home. The most susceptible to the disease are young kittens, long-haired kitties, kitties with pre-existing health issues and those raised in overcrowded shelters.
Psychogenic Dermatitis
Psychogenic dermatitis is a disorder usually caused by anxiety, stress or boredom, each of which can cause Kitty to obsessively over-groom. His tongue has tiny barbs on it, giving it that “sandpaper” feel when he licks you; it can cause a lot of damage to his skin. His fur will come out, and he can develop open sores. Topical treatments are usually ineffective, since he'll just lick the medicine away. His vet may give the cat oral medication and prescribe an Elizabethan collar, or kitty cone, to stop the licking.
If the source of environmental stress can be determined, such as a change in the home such as a new dog, find a way to remove the stressor -- keeping the dog outdoors, for instance -- and eliminate the response.
Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.
References
- "The Encyclopedia of the Cat"; Michael Pollard
- The Cat Health Guide: Cat Losing Hair (Cat Alopecia)
- The Cat Health Guide: Cat Ringworm Symptoms and Treatment
- Lyne Animal Hospitals: Psychogenic Dermatitis in Cats