Why does my cat have bumps on his back after changing food?

Thanks for using Petco Pet Education Center, formerly Petcoach! This is likely a skin infection which may be secondary to something like allergies. The infectious component would have to be taken care of but it is crucial to take care of the possible allergy as well so this does not continue to happen. It really comes down to figuring out what is causing his allergies so that they can be treated or the specific allergen avoided. There are many things that can cause allergies though in most cases they can be broken down into 3 big categories: flea, food and environmental allergies. Allergies are usually worked up in a stepwise fashion starting with flea allergies as this is the easiest and cheapest to take care of. If not on a flea preventative, then it would be a good idea to get started on one. If already on one then it would be a good idea to change to something else (there are many new products out in the market). If not improved in 1-3 months then it is time to move on and check for food allergies by switching to a novel diet (new protein and new carbohydrate). If that does not seem to be the issue then you are left out having to check for environmental allergies which require blood and/or skin tests. Allergies can be very frustrating to deal with at first but so rewarding at the end when we are able to treat them effectively!

Hi there, it is hard to give you a specific answer regarding these bumps without seeing them, but I will try and give you some suggestions. If the lumps have just come up and feel soft they could be urticaria from an allergic reaction. Likewise if they are fairly new and are red or hot they may be caused by a skin infection. However, if the lumps have been there for a while again they could be infection but they could also be little growths in the skin. Have a good feel and if they are under the skin and soft they could be fatty lumps. If they are hard and in the skin they could be cysts, and if on top get may be warts. Unfortunately there is also the possibility the growths could be tumours. If you like you can repost with some photographs or more information and we can try and help more. I would recommend going to the vet to have he lumps checked f they have been there for a while. If they have just come up and don't look infected you could wait a day or so and give an antihistamine in case of allergic reaction.

I recommend to have her examined. This spots may not be related to the diet and they could actually be something like ringworm which can spread to humans. if the lesions become a chronic issue, your best option to rule out food allergy is to feed a hydrolyzed protein diet and conduct a proper food trial. I hope this helps.

Pixie could be having an allergic reaction but an early skin infection is also possible. If more bumps appear, or these do not go away with using a mild shampoo bath, I recommend she get checked out by her veterinarian as she may need antibiotics for an infection.

Thank you for submitting your question regarding Louie. I would recommend that he sees his veterinarian to ensure he does not have ringworm. It can start out looking like his nose does. True food allergies typically present with vomiting and diarrhea as well as red itchy skin and hair loss. If the lesion does not resolve within a few days, he will need to be seen. I hope this information helps!

Hi and thank you for using Petco Pet Education Center, formerly Petcoach. Bumps on the head and neck with missing fur may indicate an allergy. Often flea allergy in cats can present like this or food allergies or environmental allergy can also cause this. I recommend getting Selene on a good prevention such as Advantage if she is not on flea prevention. If she is itchy, the bumps have any discharge or painful she needs to go to the vet to see if she needs additional treatment or diagnostics.

There are several types of food allergy. If you have not had any luck with the brands you have tried, I recommend to try a prescription brand made by Royal Canin called Ultamino. The protein is broken down to the amino acid level, thus it will not trigger an immune response. Basically you need to feed this diet for 8 to 12 weeks. During this time she cannot eat anything else. No treats, no canned food, nothing. At the end of the 8 to 12 weeks, if her skin is all cleared up, then you know it is food. If her skin is not cleared up, then it is not likely food and you should look into other causes. I hope this helps and please feel free to post any additional questions!