Expert: Jessica - 1/27/2012

Question
Hi, I'm a travel RN and my indoor cat was exposed to fleas. She was very sensitive to them loss of hair on her back from tail up spine about half way. I treated her and the fleas are gone however I noticed that in that same area her skin is discolored  (a blueish purple color) and she has been acting strange she growls and hisses at herself with noone around. She is eating, sleeping and drinking fine. I have two cats but from what I can tell she is going to the litter box fine. Could this just be a sever bruising that hurts her? Im not sure that is it though because if I push on that area she doesn't mind or hiss??? I'm at a loss but feel bad for her and don't know what it could be? Her hair is starting to grow back and I check regularly for fleas (she is indoor and no longer exposed to other animals. Anyway just need to know ideas or if I should take her into vet. Thank you for your time :)

Answer
Hi Maggie,

Skin can become discolored as the result of scarring, or during the healing process of dead skin, or even from exposure to cool air in certain cats.  A condition called stud tail can also lead to blocked pores and darkened skin in this area. Bruising would be an unusual response to fleas, but it could be present for any reason, including self-infliction.

Ultimately, you'll need to have a vet look at her to determine what's going on. I think considering her symptoms, it might be wise to ask your vet about a conditioned called Feline Hyperesthesia Syndrome. This causes unexplained pain on the back, particularly close to the tail. The cat suffers episodes of pain, usually a few times a week. During the episode, the cat often hisses, growls and even may chew at her back or tail. She may dash through the house or hide as if trying to escape the pain.

FHS is thought to be related related to a seizure disorder in most cases, but it has strong ties to anxiety, as well. For these reasons, anti-convulsants and antidepressants are the mainstay of treatment.

Good luck!
Jessica