Cat Hair loss problem

Question
My cat Aibou is about 2 years old, and recently developed bald spots.

It began at the back base of her tail, now the backs of her legs are bald, and most recently her front legs are loosing hair. There had been no change in her behavior and my other two cats Pierre and Shadow have no symptoms of any kind. Could it possibly be a food allergy? She is mostly an indoor cat, but all three of my cats like to spend time in the fenced back yard, but that is the extent of their outdoor experience. Aibou herself never really likes to leave the house, but maybe the boys are bringing in an allergen.

I'm not sure if I want to put her through the stress of taking her to the vet if there is nothing home treatably wrong, she is absolutely terrified of the car and places away from the house.

Answer
It is possible she's got a food or environmental allergy.  It's possible she's got some kind of mite, a bacterial or fungal infection, auto immune disease, or even that she's overgrooming.  There really isn't anything you can do for her without first determining what the problem is.  I can understand avoiding bringing her to the vet because you don't want to stress her.  However, if she begins getting any raw spots on the skin, she definitely needs to be seen.  Regardless of the underlying cause, most cats carry staph on the fur.  And if they get scrapes from their tongues, staph can enter the bloodstream and travel to any place in the body, causing a potentially deadly infection.  So certainly, if her behavior changes or she develops lesions, a vet visit is a must.  Other than that, there's not a terrible lot you can do for her.