Allergies, ringworm infection, stress and parasites are common causes that may result in hair loss in a cat, according to WebMD. Some pure-bred cats, such as the Himalayan and Bengal breeds, are genetically predisposed to having hair-loss problems, and others are born with a harmless skin condition resulting in chronic hair loss. In rare cases autoimmune disorders, such as diabetes and thyroid conditions, and cancer in older cats may result in hair loss.
Parasites, such as fleas, ticks, mites and lice, often cause a cat to lick and scratch her fur excessively, resulting in hair loss and possible sores, states WebMD. Parasites are easy to treat with medicine. A ringworm infection is the result of a fungus that causes a scaly ring and hair loss in the infected area. Ringworm treatments include antifungal creams and ointments prescribed by a veterinarian.
Hair loss as a result of food allergies requires a complete change in diet for the cat, informs Animal Planet. Foods that are free of dyes and excessive additives, such as canned food with only a few, simple ingredients, and foods that are fish-based or poultry-based may help alleviate symptoms in a cat. If the cat is allergic to an item in his environment, the owner may replace the item with a hypoallergenic version, such as hypoallergenic bedding, or switch to using greener products to alleviate symptoms.