Visiting Vet: What makes Groucho itch?

Sometimes the answer is something very ordinary.

Why is your cat scratching? — WikiMedia Commons

Groucho, a rescue kitten from South Carolina, arrived on the Vineyard with an upper respiratory infection (URI). These colds, common in young cats from shelters, are caused by various viral or bacterial organisms. Usually mild, self-limiting illnesses, occasionally URIs can be more serious, particularly in the very young, very old, or immunocompromised. Soon after his adoption, Groucho’s new owner brought him to me with a complaint of wheezing and sneezing. I wasn’t overly concerned. He had a runny nose and weepy eyes, but no fever or loss of appetite. Probably feline herpes virus. He was taking L-lysine, a supplement provided by the rescue organization, to reduce virus replication. Often URIs resolve without treatment in seven to 10 days, but since Groucho’s had been going on for many weeks, I prescribed oral antiviral medications and eye ointment.

Two months later, Groucho returned. His URI was completely resolved, but his owner was concerned about his ears. “He scratches them a lot,” she said, “and doesn’t like me touching them.” I checked thoroughly for evidence of fleas. All clear. I examined his ears with my otoscope. Nothing unusual. “All cats scratch sometimes,” I said nonchalantly. Thinking this might just be Groucho’s normal grooming habits and personality, I sent them home with nothing but a recommendation for “tincture of time.”

Five months later, they were back. “He’s constantly scratching his head and neck,” his owner reported. This time there were small scabby areas on Groucho’s neck, and a smidgeon of creamy white discharge in his ears. I smeared a little ear goo on a slide, stained it, and examined it under the microscopic. Bacteria or yeast might indicate an ear infection, explaining the sensitivity and itchiness, but I found nothing. “I suspect he may have allergies,” I concluded. Oral or injectable medications like corticosteroids are often used to control itchiness in these cases, but can be mildly immunosuppressive. In cats like Groucho, who carry feline herpes virus, systemic cortisone can precipitate URI recurrences. Instead, I dispensed medicated lotion to apply topically to his ears and scabby areas, and advised if excessive scratching persisted, to consider allergy testing and a hypoallergenic food trial.

The scratching persisted. Groucho’s owner opted to start by ruling out food allergies. We reviewed exactly how to do this scientifically — it’s more complicated than you think — and started him on specific prescription diets. But two months later Groucho was even worse, spending several hours daily scratching his head and neck, and pulling out fur from his legs and underside. “So it’s not the food,” I said. I wasn’t surprised. Food allergies are fairly uncommon in cats. “The next diagnostic step would be testing for inhalant allergies,” I continued, not expecting a positive response. In my experience, people are often reluctant to pursue this, cat owners even more so than dog owners. I was delighted when Groucho’s mom immediately nodded in agreement, saying, “We need to figure this out.”

Inhalant allergies can be triggered by all kinds of things — pollens, dusts, molds, danders. Cats usually present with a history of licking, chewing, scratching. Sometimes they have recurrent skin or ear infections. Symptoms may include scabs, rashes, bald patches, moderate to severe scratching, and/or self-trauma on the face, head, neck, belly, limbs, ears, back, and/or paws. Signs generally occur by the age of 3, and may fluctuate seasonally. There isn’t one simple treatment. Good flea control (since fleas make everything worse). Medications to control itching. If necessary, antibiotics for secondary bacterial infections. Topical and/or oral essential fatty acids to fortify the skin.

To actually get to the root of the issue, rather than just treating symptoms, we must identify what Groucho is allergic to, then, if possible, minimize exposure, and use immunotherapy, also called desensitization, to try to reduce the severity of his reaction. Desensitization involves very gradually exposing his immune system to tiny but increasing doses of the allergen, by injection or oral drops. It can take anywhere from four to 12 months to see a response. Not every animal benefits, but for those that do, it can make a significant difference in quality of life and need for other medications.

While awaiting test results, Groucho got a long-acting cortisone injection to relieve his discomfort, and started back on supplements to minimize risk of URI recurrence. When his allergy report arrived, I scanned the first page. No allergy to 13 different grasses. No allergy to 18 types of weeds. No allergy to 35 trees. I turned the page. Groucho wasn’t allergic to mold or fleas. He wasn’t allergic to dogs or feathers. Ah. There it was. Groucho was allergic to house dust mites.

House dust mites are microscopic bugs that live in our homes. Everyone’s home. They are not a reflection on your house-cleaning skills. They are just everywhere. Don’t get confused. These aren’t like mange mites, that live and breed on the animal’s skin. House dust mites hang out in the environment wherever people and pets hang out, feasting on bits of skin and dander we leave behind. Groucho gets exposed to mites in house dust, then has an allergic reaction which makes him itch all over.

Environmental control is challenging. House dust mites love mattresses, bedding, carpets, and humidity. Here’s what helps. Wash all bedding weekly in very hot water. Keep pets off beds and furniture. Consider plastic covers. Discard feather pillows. Cover pet beds with plastic, or treat with pet-safe insecticides. Wash pet beds weekly (the stuffing too), and replace entirely twice a year. Same goes for stuffed toys. Avoid knickknacks that collect dust. Wash curtains weekly, or replace with blinds. Remove carpet. Mop floors frequently. Change furnace filters often. Use a dehumidifier to reduce dampness.

All of that is a tall order for any owner, so desensitization immunotherapy is also key. We are teaching Groucho’s mom how to give allergy shots, and hoping they help. What a lucky little guy to have landed in the lap of someone willing to go that extra mile. Gesundheit!