There are many things for which vets will prescribe corticosteroids, usually for inflammation, but for other things as well. They work by suppressing the immune system, which helps reduce inflammatory responses. For that reason, they can also treat autoimmune disorders. However, as with any medication, these medicines have side effects. The question is, are corticosteroids safe?
Dr. Karen Becker worries about how common the use of corticosteroids is in veterinary medicine. According to an article she wrote on Healthy Pets, what's happening is that vets are treating the symptoms of a condition without treating the condition itself. Corticosteroids often work so quickly on symptoms that it's often difficult not to prescribe them when a pet is sick.
She says that prolonged use can lead to serious problems, like Cushing's disease and other organ disorders. And, while cats tend to tolerate steroids better than dogs, Dr. Becker prefers trying alternatives before resorting to steroid treatments.
However, according to Dr. Elyse Kent, the side effects of steroids can almost always be reversed in cats. This includes diabetes mellitus, which can happen in cats that are predisposed to the condition, and taking steroids. Dr. Kent says that, if the diabetes is, indeed, related to the steroid use, then the condition will go away as the cat is tapered off of the medicine.
The alternatives that Dr. Becker prefers are plant-based sterols and sterolins, instead of the synthetic hormone corticosteroids. She also recommends trying to find out what's causing your cat's condition, or what's triggering allergies. By identifying the underlying cause, your cat has a better chance at full recovery, and less chance of suffering side effects of corticosteroids.
The bottom line, however, is ask questions, and listen to your vet's recommendations. Ask if there's a possibility that some underlying problem is causing your cat's symptoms (or ask for an allergy test if allergies are the problem), and find out what it will take to identify and treat that. If, after discussing all the possibilities and alternatives, your vet still feels steroids are best, then go with that. In most cases, steroids are safe for your cat, and they do help many conditions.