INTRODUCTION
General advice only. Please consult your family Veterinarian for your specific cat!
The most common skin allergies causing a dermatitis (hair loss, crusty, inflamed skin, bumpy rash) in cats are from flea and food sensitivities. Other allergies include atopy (seasonal and environmental) or contact allergies. We also see ringworm, and much less commonly, skin mites and lice.
FLEA ALLERGY
Flea Allergy is one of the most common causes of dermatitis in a cat. Skin can look a bit scabby or crusty, and there can be hair loss (especially on the rump). Some cats are allergic to flea saliva and have severe breakouts even with only one or two fleas. It can sometimes be difficult to find a flea. A good place to check is on the rump or the belly.
In severe flea infestations, you may need to treat your house and yard. Flea control for your cat may need to be applied all year round as fleas can overwinter in your house.
Make certain you are using good flea control (on all your cats and dogs!). Ask your Veterinarian for advice regarding safe topical or oral flea products. Some over-the- counter brands can cause toxicity depending upon the ingredients (usually those containing Pyrethrins or Permethrins). Cats who have been exposed to toxic levels of these types of ingredients may show symptoms within a few hours. Clinical signs can range and progress from drooling, vomiting and diarrhea, to staggering, seizures, and even death. Seek Veterinary help immediately.
NOTE: Never use a dog flea product on your cat! Many cases of toxicity are from misuse of products.
FOOD SENSITIVITY/ALLERGY
A good diet is extremely important for cats !
Diet is so controversial, but I generally recommend well-known brands. The traditional brands spend a lot of money in nutritional research. Some newer brands of food seem to pop up frequently . They may have have good ingredients, or they may not. Pet food should be US-FDA certified. You can check for a previous history of food recalls from the FDA. FDA LINK
In general, I don't like kibble that has red or green dyes, and I don’t recommend the semi-moist / pouch foods. I am okay for a trial of Frozen Raw (ie Natural Instinct Raw) if an owner wants to try. (Your Vet may disagree with that statement). I like cats to get a combination of canned & dry food.
If your cat is an otherwise healthy, young cat with no other underlying medical issues, and you are still and still having skin issues, there are some over-the-counter cat diets specifically labelled for 'sensitive skin' or 'sensitive skin and stomach' that could be tried. Slowly wean onto the new diet.
Note - some cats are extremely picky, and may not transition to new food. Caution is always recommended when changing diets. Never let your cat quit eating. Otherwise, we usually recommend trying any new diet for at least 2 months to look for improvement, unless symptoms dramatically worsen.
I am not a fan of excess treats for cats. Be conservative and also check your treats for 'bad ingredients' such as high fructose corn syrup.
Clean out your food bin in between new bags of food, if you use one (grain mites can become an allergen source).
You can also consider a consult with UC Davis Veterinary Nutrition Experts, and they provide nutrition consults if you are interested in consulting with experts. UC Davis Vet Nutrition Consult
ATOPY (SEASONAL & ENVIRONMENTAL ALLERGIES)
Some cats have seasonal allergies (during high pollen counts), or environmental allergies (ie molds, house dust mites). Your family Veterinarian can give medications as needed.
If your cat is having chronic skin issues, your Veterinarian may refer you to a Veterinary Dermatologist. There are more specific skin tests that can be done to isolate your cat’s problem. (Blood test or intradermal skin test for specific allergens. Note - these tests are less accurate for food allergies.
Your Dermatologist may actually start with Food Trials before more specific skin testing. They will often start with Prescription Food trials utilizing Hydrolyzed Protein Diets or Novel Protein Diets. You may prefer to discuss these diets with your family Veterinarian before a referral.
RINGWORM AND SKIN MITES
Ringworm can be an issue in cats (usually kittens) . Sometimes, it can be seen in catteries or animal shelters. Ringworm is a fungal infection and is zoonotic, meaning you can catch this fungal disease from your cat. Feline skin mites such as feline demodex and scabies are rare. There is only one species of feline lice (Felicola subrostrata) and it is not contagious to humans.
Your Veterinarian may need to do a DTM test (fungal culture), or a skin scraping or cytology to diagnose these conditions. Treatments may vary depending on the size of your cat, and severity of the condition.
GROOMING
Some cats have very long fur than can get extremely matted and contribute to skin breakouts. Try to keep your long haired cats combed (I like the steel combs). Mats may need to be shaved out, and your Veterinarian or Groomer may have to help with this.
It is very easy to accidently nick or cut your cat when trying to use scissors to remove a mat! You may need to see a professional groomer in your area for a Lion Cut shave down and bath for a severely matted cat. Many cats will need sedated for an extensive shave down, so discuss needs with your family veterinarian and groomer to coordinate.
CONCLUSION
For severe or chronic itch, redness, or general dermatitis in your cat, please consult your family Veterinarian. They will recommend proper medications or diagnostics.
Skin allergies are frustrating problems! But a proper diet and good flea control will actually save you money and solve most of your problems. A skin supplement containing Omega 3 fish oil (ie Nordic Naturals) may also be extremely beneficial.
Your family Veterinarian can help with the rest!