With the exception of hairless breeds such as the Sphynx, cats are known for their furry pelts, so if a cat starts to lose his coat, it’s justifiably cause for concern. How can you distinguish between normal shedding and abnormal hair loss? It’s easy: Shedding doesn’t cause bald spots. If the skin is visible, best to schedule a veterinarian exam or ask for a referral to a dermatologist.
Hair loss, or alopecia, takes two main forms, says dermatologist William H. Miller, VMD, Medical Director of the Companion Animal Hospital at Cornell University College of Veterinary Medicine:
“The hairs fall out spontaneously.” Though it’s a rare occurrence, spontaneous hair loss can be related to stress, endocrine diseases such as Cushing’s disease (an overproduction of cortisol by the adrenal glands), hyperthyroidism (excess production of the thyroid hormones), and some forms of cancer, including lymphoma, liver or pancreatic cancer.
An unusual form of spontaneous hair loss can develop when cats go to the veterinarian or some other stressful place. The experience can activate the cat’s arrector pili muscles, which are attached to the hair follicles. This causes him to suddenly shed massive numbers of hairs that have been in the resting phase of the hair-growth cycle. Fortunately, this condition is harmless, and the hair will grow back.
“The hairs are broken off by scratching or chewing.” The condition is known as traumatic hair loss and is the most common form. “Cats with hair loss typically are licking the hairs off or pulling them out because they have an allergic or behavioral condition,” Dr. Miller says. Allergies to substances in the environment such as pollen or ingredients in their diets can cause the skin to itch, and scratching and chewing ensue.
Determining the cause of hair loss requires a complete clinical and laboratory evaluation. In some cases, a skin biopsy may be necessary. If medical causes have been ruled out, the cat should be evaluated by a veterinary behaviorist to determine if he has a compulsive disorder causing excessive grooming.
Endocrine disorders and allergies can be treated or managed with medication, changes in diet or allergy shots. “If the cat has a treatable disease, he usually will respond nicely to treatment,” Dr. Miller says.