Dear Dr. John,

My daughter owns a mixed breed cat that is very aggressive at times and can seem to almost act neurotic. She did some research on this condition. Apparently, it’s called Hyperesthesia Syndrome. The cat’s skin seems to move on her back in weird ways, almost as if she is uncomfortable. Is there a specific cause?

When it starts up, she is prone to growling and hissing. Is there anything that can be done to reduce this cat’s aggression towards people and even my cat when they come to visit for extended periods of time? Her cat is a spayed female that is now five and she seems to have almost gotten worse as time has gone on.

— L.A.

Dear L.A.,

Your daughter’s research is correct, and the condition is known as Feline Hyperesthesia Syndrome or FHS. Certain cat breeds are more typically affected including Siamese, Burmese, Himalayans, and Abyssinians. Skin on the back, usually near the base of the tail, or anywhere on the body twitches and the cat is often in a state of hyperexcitability too. They act as if they are in pain which can lead to aggressive behavior with short outbursts. It is also not uncommon for the cat to make noises that are also suggestive of discomfort.

All of this falls into the broad category of neurological conditions. The cause is not known and can be a combination of several factors including stress, allergies, ectoparasites, and more. Another cause listed in the literature is moving or any environmental changes. Everything you write seems to confirm the possibility of FHS and I would advise your daughter to have the cat seen locally and possibly by a veterinary behavior specialist. She should take videos to document the condition when it occurs so a veterinarian can see what is actually going on.

Treatment or eradication of the clinical signs include changing the environment to reduce whatever may cause the cat to be stressed and it sounds as if this cat could possibly benefit from various pheromone products or anxiolytic medications. Good luck!

Dr. John de Jong is President of the World Veterinary Association. He owns and operates the Boston Mobile Veterinary Clinic and can be reached at 781-899-9994.