What could be wrong with our cat if he has irritated, lumpy skin under his arm?

skin irritations are often caused by an allergy to an ingredient/s in the cat’s food. Try a high quality cat food with a minimal amount of grains; corn and soy are common irritators for cats. Also, if you can afford it, and there is one available to you, try a holistic vet. My holistic vet has extended the life of my cat that has heart problems; traditional vets are stunned that she is still alive.

I would be more worried about the fact that your cat has an arm.

It’s time to have your vet refer your to a veterinary dermatolgist or an internist. They may need to do a small biopsy to determine what’s going on.

If your vet thinks that it’s immune mediated, he may suggest putting the cat on a course of steroids to see if it improves. Please use caustion when using steroids and make sure that your vet explains the risks involved.