What to Do About Unexplained Hair Loss

For feline lovers and enthusiasts, cat hair is a fact of life. There are countless T-shirts and mugs with cute sayings like “Everything tastes better with cat hair in it” or “No outfit is complete without cat hair.” Yes, cats shed, but it’s a small price to pay for the love and happiness they bring us.

©Thorsten Nilson / EyeEm | Getty Images
Last Updated on November 8, 2022 by Natasha Medvetsky

For feline lovers and enthusiasts, cat hair is a fact of life. There are countless T-shirts and mugs with cute sayings like “Everything tastes better with cat hair in it” or “No outfit is complete without cat hair.” Yes, cats shed, but it’s a small price to pay for the love and happiness they bring us.

When cats shed normally, their coat appears just fine. However, if your cat is looking a little on the bald side, there may be something going on besides normal shedding.

What causes hair loss?

The medical term for hair loss is “alopecia,” and it is a common problem in cats. Feline alopecia can be divided into two broad categories: spontaneous and self-induced.

✔ Spontaneous hair loss means that the hair is falling out, which is often a result of systemic diseases, most notably glandular disorders like an underactive thyroid or overactive adrenal glands.

✔ Self-induced is from cats who lick, bite or pull their hair out. This is often because either their skin is itchy or for psychological reasons.

Why cats have itchy skin

There is no shortage of causes of itchy skin in cats. Skin parasites, infections (bacterial or fungal) and allergies are common conditions. Although cats get lice and mite infestations of their skin, this is an infrequent problem. Here are some of the most common conditions and how to treat them:

©Thorsten Nilson / EyeEm | Getty Images

Fleas. By far, the most common itch-inducing and hair loss-producing feline skin parasite is the pesky flea. Flea infestation is diagnosed by carefully inspecting the skin. Live fleas can often be seen when the hair is parted. Sometimes, if you turn a cat over on his back, you might see one or two fleas scurrying across the abdomen.

In many cases, live fleas aren’t detected; however, multiple brown specks of “flea dirt” (the polite veterinary term for flea poop) is noted during the exam. A hair coat containing flea dirt has the appearance as if someone sprinkled pepper on the cat and is a telltale sign that fleas are an issue.

Treatment: Flea infestation is easily remedied with once-a-month topical flea control products. The best, most reliable products are obtained through your veterinarian.

Flea allergy. Some cats are allergic to flea bites, specifically to the saliva that the flea injects into the skin as it bites. Even if fleas and/or flea dirt aren’t detected, flea allergy might be the culprit, as it only takes a single flea bite to produce an intense reaction in some allergic cats.

Treatment: Besides monthly topical treatment, a short course of oral corticosteroids and/or antihistamines may be warranted in cats with concurrent inflammation and itching.

Ringworm. This is the most common infectious skin disease in cats. Any age, sex or breed may be affected, although young cats, older cats and long-haired cats are more frequently affected.

Ringworm varies in its ability to induce itching. Some cats with ringworm don’t seem to be uncomfortable, while others scratch and lick at their skin constantly, resulting in self-inflicted hair loss.

Ringworm is a “zoonotic” disease, meaning that it can be transmitted to humans. If your cat has a circular, crusty skin rash, and you have a similar rash, it’s likely that ringworm is the culprit.

I had a client who went to her doctor because of a skin rash just above her upper lip. Her doctor asked her if she kisses her cat. “Of course I kiss my cat,” she said. “Well, you have ringworm, and you might want to get your cat checked.” Sure enough, her Persian kitten did have ringworm.

Treatment: Ringworm treatment options vary, depending on the situation (an individual cat versus cattery or multiple cat household, long-haired cats versus short-haired cats, etc.),but may involve some combination of clipping the coat, topical therapy (usually medicated shampoos), oral medication and environmental decontamination. Treatment is often successful if clients are diligent about following the prescribed protocols, but there’s no denying it: Ringworm treatment can be a major nuisance.

Food allergies. Adverse reactions to food may manifest themselves via the skin. You may see:

  • severe, generalized itching
  • little scabs and crusts throughout the haircoat (called “miliary dermatitis”)
  • itching around the head, neck, ears and face
  • self-inflicted hair loss due to overgrooming

A food allergy may show up first in the skin as small red spots, which can turn into scabby or crusty sores that become infected as the cat rubs or scratches them. Itching around the head and face is common; however, there are many cats whose only sign of food allergy is self-induced hair loss.

Treatment: Dietary elimination trials, in which the cat is fed a diet containing a protein source he hasn’t encountered before (such as duck, rabbit or venison) are necessary to obtain a definitive diagnosis. Your veterinary office likely sells these specialized hypoallergenic diets. These trials require patience on the part of the cat owner, as it may take anywhere from three to 12 weeks before you see improvement.

Airborne allergies. Allergic reactions to airborne substances (known as atopy), such as pollen or dust, can lead to itching and subsequent hair loss from excessive grooming. Itching that appears to be seasonal is suggestive of atopy, although many cats with atopy can be itchy year-round, if the allergen is in the environment all the time.

Making a diagnosis of atopy can be challenging. Blood tests can be performed to see if the cat is allergic to plants that are native to a particular geographic region, as well as to common household dusts and mites, although many dermatologists feel the blood tests to be unreliable. Intradermal skin testing, in which tiny amounts of allergenic substances are injected into the skin and the skin reaction noted, is a more meaningful diagnostic test. Dust mites and molds are the most common airborne allergens, with some cats having concurrent reactions to seasonal pollens. Intradermal skin tests should be performed by an experienced veterinary dermatologist.

Treatment: The ideal treatment of an airborne allergy is to identify the allergen if possible, then remove it from the environment. This is usually impractical, especially in patients that are allergic to airborne pollens.

Hyposensitization — serial injections of progressively larger amounts of the offending allergen — is probably the most appropriate long-term control method for cats with a prolonged allergy season. This treatment requires a significant time commitment and dedicated owner. Ultimately, most owners opt to try more common therapies such as antihistamines, omega-3 fatty acids and corticosteroids. Although corticosteroids have the potential to have side effects, the doses necessary to control allergic dermatitis are unlikely to cause problems, especially in cats, as cats are more resistant to the undesirable side effects of steroids as compared to dogs.

Psychological disturbances. Cats who pull, bite at or overgroom their fur do this despite the fact that their skin does not itch. We call this “psychogenic alopecia,” and it is usually a manifestation of stress, fear, anxiety or nervousness. Examples of stressful events in a cat’s life include a move to a new home, a short stay at a boarding facility, a new pet or baby in the household, or territorial competition in a multiple cat household. In some cases, however, the cause of the stress may not be so obvious.

Grooming is a comfort behavior, often used by cats to relax themselves. Think about the last time your cat did something silly or clumsy, like misjudge a leap or accidentally tumble off a chair. We might chuckle, but the cat immediately grooms. Whether they feel embarrassment is debatable, but it shouldn’t be surprising that in the face of stress, cats may turn to excessive grooming to dispel their anxiety

Once parasites, allergies and other medical problems have been ruled out, psychogenic alopecia must be considered. Cats of Asian lineage (Siamese, Abyssinians, Burmese and Himalayans) are more susceptible to psychogenic alopecia, presumably because of their high-strung, nervous temperaments.

Treatment: Ideally, the treatment of psychogenic alopecia would involve the elimination of the potential sources of stress in the cat’s environment. Unfortunately, this is often difficult or impossible, and anti-anxiety medications are often warranted to control the problem. These medications are usually effective, and many cats can eventually be weaned off of them.

Time to see a specialist

Even an experienced cat veterinarian occasionally fails to achieve a diagnosis (or, more frustratingly, they achieve a diagnosis but the cat does not respond to therapy). In these cases, it may be necessary to seek out a true expert — a veterinary dermatologist. In these days of specialization, veterinarians have access to a variety of experts, and most general practitioners can refer their challenging skin cases to a nearby board-certified or qualified dermatologist should the need arise.

These veterinarians specialize in one body system — the skin — and this allows them to recognize clinical signs and disorders that a general practitioner might miss. Veterinary dermatologists are also likely to be familiar with novel treatment options that have not yet filtered their way down to general practitioners.

Your veterinarian can refer you to a veterinary dermatologist or you can find one at the website of the American College of Veterinary Dermatology at acvd.org.

About the Author

Dr. Arnold Plotnick
Dr. Arnold Plotnick
Dr. Arnold Plotnick is the founder of Manhattan Cat Specialists, a feline-exclusive veterinary practice on Manhattan’s upper west side. He is also an author of The Original Cat Fancy Cat Bible. Dr. Plotnick is a frequent contributor to feline publications and websites, including his own blog, Leisure Commando. He lives in New York City with his cat Glitter.

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