Fur pulling

My cat (medium length hair) is pulling his fur out in tufts while grooming. When we first discovered large tufts of fur on the floor and bed we thought he'd been in a fight with one of the other two cats in the house, but found no sign of injury in any of them (other than the lost fur). We kept finding new tufts and clumps, almost always in his favorite nap spots. After a week of the mysterious clumps of fur I finally caught him doing it to himself while grooming. He's biting tufts of fur off and spitting them out on the bedding then going back to grooming like it's no big deal. There's no excessive scratching or any other sign of skin irritation, but his fur on his sides is starting to get thin. You can almost see his skin without pushing the fur apart to do so. What could be causing this behavior?

[Kimberly Coyner, D.V.M., DACVD]

Fur pulling is most commonly due to itchy skin caused by parasites such as fleas or microscopic mites, food allergy, or pollen/dust allergies. Make sure your cat is on a good monthly flea preventative such as Advantage or Revolution. In older cats, fur pulling can also be a symptom of an underlying internal disorder, such as hyperthyroidism, spinal arthritis/pain, kidney pain, etc. so if he has not had his yearly geriatric bloodwork recently then now would be a good time. Lastly, stress or intercat aggression can cause fur pulling due to "psychogenic alopecia", but this is a disease made by ruling out all other medical causes for the problem. I recommend starting with a recheck exam by your veterinarian for a good physical exam and then proceeding from there.
Good luck,
Kimberly Coyner, DVM DACVD
www.dermvetvegas.com