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Cat Skin Allergies

January 14, 2010
Liz the allergic domestic long hair cat ignores her veterinarian

Beautiful Liz practices, "If I can't see you, you can't see me at the vet's office."

Sometimes a Cat Itches All the Time!

A beautiful brown-black long-hair tabby kitten stared out of her black Sherpa soft-sided carrier. She hissed. Our formal introduction deteriorated into cajoling and negotiating as I snuck a full physical examination in between angry kitten hisses. My first visit with little Liz ended 20 minutes after our introduction. She was obviously displeased with me. I fell in love with her.

Normally, I see a cat once or twice a year. If they despise the veterinary visit, at least a year or so rolls by in between appointments. Liz came back one week later!

Some cats run around the house, madly dashing with tail arched up and paws flying, biting ankles, tearing around corners, frisking curtains, and gnawing electrical cords. Liz added frantic hair pulling and self mutilation to the repertoire.

Cat Skin Diagnostic Work-Up

That first, “Can you check the itch?” visit involved into skin scrape cytology, skin tape cytology, ear swab cytology, and ringworm culture (called “worm”, not a worm!). Basically, samples from the surface of the skin, prepared and analyzed under the microscope. Some critters, like sarcoptic mange (insects), and ringworm (fungus) infect people; they are zoonotic diseases. Liz came up clean.

Doc Truli lists the tests needed for a basic first, thorough dermatology visit:

  • Skin scrape cytology
  • Skin tape cytology
  • Ear swab cytology
  • Ringworm culture (called “worm”, not a worm!).
  • Basically, samples from the surface of the skin, prepared and analyzed under the microscope. Some critters, like sarcoptic mange (insects), and ringworm (fungus) infect people; they are zoonotic diseases.
  • A note about the ultraviolet light test (Wood’s Lamp Test): 50% of ringworm fungi species will glow candy-apple green along the hair shafts under the UV light. Your veterinarian will still need a fungal culture test to speciate the fungus. ┬áThis test takes 1-3 weeks to grow.
  • Try This at Home to Decrease Itchy Skin

    We instituted strict flea control, oatmeal hypoallergenic baths, and high quality food with balanced omega 3: omega 6 fatty acids at a ratio of 1:5.

    Official Cat Allergy Testing

    Still itchy weeks later. We drew blood for allergy testing from a reputable laboratory. Liz tested 5/6 (seriously allergic) to several allergens:

    • Black ants
    • Sheep wool
    • Human dander
    • And various grasses, ragweed, palm trees

    Here’s How a Conversation About Cat Allergies Goes:

    She’s a sweet little indoor cat in South Florida. The intense allergy to black ants and sheep wool stumped this doctor until I spoke with her parents.

    “She catches these huge black ants in the house, plays with them, and eats them.”

    “How often does she find ants?”

    “Almost every day.”

    (For those of you who do not live in a sub-tropical climate, while ants in the house sounds gross and irresponsible, remember: there are bugs all over down here. It barely matters how clean or meticulous you are.)

    “Um, can you, maybe, call an exterminator?”

    (Just call me Doc Obvious.)

    “Now, why would a hot climate like Florida lead to sheep wool in a cat’s environment? Most people down here have tile or hardwood floors.”

    “Not us, we have Berber wool carpets. And we custom ordered Liz a real sheepskin cat bed.”

    Whoa! Who would’ve guessed? (Whodathunk.)

    “Let’s start by replacing the cat bed. What can be done about the carpet? Can she go to a part of the house without it?”

    “No, but we’re moving next month.”


    Sometimes You Just Have to Try Steroids

    Little Liz felt better for a few months, then she was back. I injected the standard cortisone to suppress her itchiness, and she felt fabulous for 2 months. We repeated this ritual until we went to monthly, then, after about 4 months of this, the cortisone only lasted 3 weeks.

    Cortisone can have significant side effects to a body, although cats are fairly resistant to most of the effects compared with people or dogs:

    • Precipitate heart failure in hidden cardiomyopathy patients
    • Trigger diabetes mellitus

    In plain talk: try not to require cortisone chronically. It might not be good in the long run.

    Custom-made Allergy Shots Avoid Steroid Side Effects

    So, we ordered custom-made allergy desensitization vaccines (a.k.a. “allergy shots”). The allergy shot serum takes about 4 weeks to arrive. 12 hand selected antigens comprise the cocktail. The cat allergy specialist assisted in the selection of useful ingredients for Liz.

    Tru Tip

    A note about allergy shots: Allergy shots take approximately a month to make because the serum sits for weeks at the customizing facility and must be tested for bacterial sterility before shipping. This process, reliant on the laws of time and nature, cannot be shortened through technological advances!

    Administering allergy shots requires finesse and practice. Pet parents usually lack both in their pet’s hour of need. Of course, it might be creepy if you were naturally good at giving shots to a cat with no training and no practice!

    Liz resisted shots like a pro. At first, she needed daily increasing doses, injected just under her skin. Her mom and dad handled these treatments fine after the nurses taught them the basics. Liz stopped itching for 6 months. She settled into a routine of monthly shots.

    After six more months, the little cat person decided she didn’t want shots anymore. So, her parents brought her to me at the animal hospital monthly. Liz abhored her hospital visits.

    Beautiful Domestic Long Hair Cat Dissapproves of her Veterinarian

    Liz, the amazing allergic cat, typically gives Doc Truli this annoyed and ready-to-hiss attitude.

    As long as this independent cat could walk around the exam room, explore, jump up on the counter, and not be touched, she was happy and agreeable. As soon as anyone *at all* tried to pick her up or cradle her, she hissed, squirmed, and attacked with her teeth and front claws. Liz became “a handful.”

    We developed a system for successful allergy shot visits:

    • Quick in
    • No see or hear a dog
    • Stay in soft carrier
    • Distract front bitey end of cat with hands and toys
    • Squash (gently) carrier around mid section of Liz, or else she’d whip around and attack
    • Inject allergy shot in nearest haunches of cat
    • Quick let go and gently close zippered door on carrier
    • Discuss briefly how much Liz hated the car and the vet

    “See you next month!”

    Then, the itchiness returned! She saw a board certified cat dermatologist who could add nothing to the case. That visit did, however, give Liz’s parents a renewed idea.

    Cat Allergy Elimination Diet

    “Doc, didn’t you tell us some cats have food allergies. And the only way to diagnose the food allergies is through an allergy elimination diet?”


    Three days. I repeat: Three days after starting Royal Canin Veterinary Diet Feline HP, Hypoallergenic, the itchiness subsided. We’re at three months and counting.

    Liz has relapsed before, but hope springs eternal. We may finally have licked the cat allergy!

    6 Comments leave one →
    1. Tracey permalink
      May 11, 2014 4:03 pm

      My cat was having a lot of scratchiness, so our vet put her on the Royal Canin hypoallergenic cat food. She got even worse, was scratching herself bloody. We got the blood test and found out that she is allergic to (among other things) duck rabbit and potato. Three of the four most common ingredients in hypoallergenic cat food. We’re working on the shots option for my scratchy girl.

      • May 14, 2014 5:26 pm

        Dear Tracey,

        Sorry to hear your cat is so itchy. Coupla points. 1) food allergy blood tests are thought to be 50% accurate, like flipping a coin. I have found them to be helpful, but not definitive.

        2) the food you refer to is novel protein, not hypoallergenic. In theory, your cat should not react allergically to a protein she’s never has before. Note *should not* does not mean will not.

        Get a different food. Like z/d or royal canine hypoallergenic (not duck and potato).

        3) it takes about 8 weeks for the body to clear out allergies to food in extreme cases. Be patient. Do not help her cheat on her diet.

        Good luck! Your veterinarian is an awesome source of help, call them!

        -Doc Truli

        • Suzanne permalink
          May 30, 2017 7:37 pm

          OH WOE IS US!!! we’ve done all of the above trying to help poor BB Boycat who not only itches, he has lesions, and loses fur, his legs and belly are the worst…he got a little better when diagnosed with hypothyroidism and got treatment but his legs are still so bad and he is taking antihistamine for the itchy-owies but we’re sliding back it looks like… I just read about the black ants, I have ant infestation every year and use the little red houses to get rid of them… am I clutching at straws here? could this be it? BB Boycat is 15 yrs old and I would like him to end his days much better than it looks from here…can you help Doc Truli???? Anyone at all….

        • June 21, 2017 12:01 pm

          Dear Suzanne,
          Skin itchiness is so frustrating. Ants can very well be a problem. You are not clutching at straws.
          -Doc Truli

    2. emily permalink
      November 25, 2013 2:57 am

      your cat looks just like my cat , do u know what kinda of breed your ca is cause i think mine might be mix with mainecoon


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