Cat pulling hair on new diet. How long till hypoallergenic food works?

Hi there! Our diet trials for patients with allergies can take a couple of months to show true improvement but usually around the one month mark the difference is noticeable. Make sure you are strictly following the diet trial and giving no other treats or food mixed in, as this will not give accurate results to your new food. Hope this helps!

I would recommend to wait up to 8 weeks before thinking about other causes. If not working, a skin scrape and more dermatological tests (including allergic testing on bloods) are required to determine if other causes are possible. Three main type of allergies are usually affecting pets: food allergies, flea and parasite related ones and environmental type (allergens coming from trees, pollens, dust etc etc). Some medications can be given by the vet in order to repair any possible skin lesions (like steroids and antibiotics). Hope this answer was helpful, but please do not hesitate to contact us again on the forum or by requesting a consultation if you have any more questions or to discuss it any further.

It can sometimes take up to two months to fully see results of a new food before any symptoms are completely gone if it is a food-based reaction. I would hesitate to keep switching foods as you won't be able to accurately judge if a food is causing it and may just cause added GI upset on top of the itching and scratching. If Jax is still breaking out very badly it would be best to contact the vet doing the food trial with you so they can take note and make suggestions on whether a change should happen or if you should stay on the food for a while longer.

Food allergies can be frustrating to deal with. A cat may show signs such as vomiting or diarrhea within hours of eating a food they are allergic to or it can take weeks to see a problem, Skin issues such as hair loss and scabbing sometimes will not occur until 2-4 weeks after a cat eats a food they are allergic to. Food allergies are typically seen in pets older than 1 year, but can be seen as young as 8-12 weeks in rare cases. If you are concerned Sweetie may have a food allergy, I would recommend discussing this with your veterinarian as they will be able to guide you in a food trial to confirm a food allergy.

It takes 4-6weeks for allergens to completely leave the skin layers. If persisting longer than this the diet should be reassessed and other triggers such as external allergies, parasites and infections should be investigated

If Maze was previously diagnosed with food allergies and they don't seem to be better yet, then they were not adequately diagnosed. First, it can take several weeks for the allergy to go away after a diet change. So, if it's been less than six weeks after the diet was switched, then you'll need to wait a little longer before you know if it worked. Food allergies are due to certain proteins and they are usually animal proteins (beef, pork, dairy, etc.). To find the actual protein Maze was allergic to, you must have done an elimination trial. If there was not an elimination trial done, then you would be only guessing at the source of the allergies. One way I often bypass the elimination trial is by recommending a hydrolysed protein diet such as Hill's i/d. In these diets, the proteins are broken down, so there is minimal chance of them causing an allergy. This would have to be prescribed by a veterinarian though. In the meantime, you may consider starting a diet trial to see if that helps to relieve the problems Maze is having. Here is a link to a good article that explains how to do the diet: http://communityvet.net/2010/03/diy-elimination-diet-for-the-dog-an-cat/ Keep in mind that your diet trial will cease to work if she is getting any treats or table scraps. Make sure that there is no possibility of this happening - especially if there are kids in the house. As always, it's recommended to do these things in consultation with your vet.

First you have to rule out other things as well like fleas and secondary infection which can both be itchy. If there are any lesions under the skin there may be a secondary infection (common with allergy). For food allergy it can take time for symptoms to resolve (8+ weeks for some dogs) and those pets who are very itchy may need medications to stop the itch (itching can lead to secondary skin infection as well). So if your pup is very itchy you may want to talk to your family vet about meds to help with itch while going back to the old food. And treat for fleas just in case (even if you do not see any). I hope this helps and thank you for using Petco Pet Education Center, formerly Petcoach!