Cat biting out her hair...

I wasn't sure if this should go into behavior or health, so if a moderator feels it should be moved, please do so...

I am submitting a question for my sister-in-law. About a year ago, she started noticing large patches of missing fur on the sides of her cat Isabelle's stomach. She brought Isabelle to the vet, who said that she was biting it out herself, most likely due to a combination of stress and dust due to some remodeling they had been doing.

Isabelle seemed to be getting better, and now she is doing it again (no construction this time). Has anyone had any experience with this type of behavior, and/or any suggestions as to why she is doing this and what can be done to help?

Thanks for your help!!

You said this happened a year ago. Is it the same time of year this time as last? Not sure where your SIL lives, so don't know if it's the dead of cold winter and her house is shut up, or recently shut up. Seasonal allergies (molds, etc)? Changes in environment triggering stress? New cleaning chemicals being used in the house? Dry skin from low indoor humidity (can make them itchy)?

Could be a number of things. Stumpy did that for 6 years and in spite of all the testing we did, never found the culprit until our dog crossed the bridge last January. He slept with the dogs and when they were gone, his skin cleared up (go figure the cat that loved the dogs the most was allergic to them).

Rule out some of the obvious (stress triggered), run blood tests to make sure there isn't anything physically wrong, do a skin scraping if necessary, and if all those are inconclusive, you probably have an allergy reaction. And like in humans, those are hard to track down.

There is a good thread on skin problems in the Health forum also.