Some common causes of hair loss in cats include fungal infections, hormone imbalances and excessive self-grooming. In some cases, hair loss is symmetrical on both sides of the cat, while other conditions cause patchy hair loss.
Some forms of feline hair loss are treatable, while others are not. Excess cortisone and excess thyroid hormone can both lead to hair loss in cats, and medications are available to help with these conditions. Ringworm and mange, which are skin infections that lead to loss of fur, are also treatable with medication and ointments.
For cats that over-groom themselves and lick or chew off patches of hair, behavioral training might help reduce the grooming behavior. In some cases, over-grooming behavior develops when a cat is stressed, so maintaining a calm environment and regular routine can help prevent excessive self-grooming.
No cure exists for hereditary disorders such as congenital hypotrichosis, a genetic condition that causes young kittens to lose their fur.
In general, most hair loss does not cause permanent damage or pain for the cat, but the underlying causes might have other, more dangerous effects, so a trip to the vet is warranted for cats that display unexplained hair loss. Redness, scabs and open wounds at the site of hair loss may require veterinary intervention.