Causes of Itching in Cats and Dogs

dog scratching
Itchy Dog, Image Courtesy of anankkml, FreeDigitalPhotos.net

Itchiness and excessive scratching and licking are common problems in pets. They’re usually triggered by parasite infestation or allergies, though emotional problems, low-fat diets, infections, and other medical issues may also cause itchy skin.

Parasites

When a pet is itchy, fleas are the most likely culprit, especially if the itchy areas are around the hips, base of the tail, thighs, groin, and/or neck.  Allergies to fleas are common, and they make the itchiness far worse.

You can check for fleas by combing your pet with a flea comb and placing any residue from the comb on a damp, white paper towel or tissue paper. If there are pepper-like grains that form a red ring on the paper, this is probably flea excrement.

Mites are another common parasite that can trigger skin reactions. Scabies mites often cause itching on the hocks, belly, ears, and elbows. Demodectic mange is more likely to attack the forelegs and face, whereas Cheyletiella mites are more likely to go for the sides and/or back. Ear mites can trigger itching in the ears and harvest mites (chiggers) also tend to favour the ears in cats, as well as the mouth area and between the toes, but they like the head, legs, and abdomens of dogs. Cats and dogs can also be infested with lice.

Not all creatures that cause itching in pets are parasites. Stings and bites from mosquitos and other insects may also cause itching. Insects often bite the ears or the nose where hair is thin or nonexistent.

Infections

Although they occasionally occur on their own, bacterial infections most often arise in response to another problem. For example, if flea bites make a pet itchy, he may scratch, bite, lick, and rub against objects until the skin opens and becomes infected.

Other types of infection that may cause itching include ringworm (a fungal infection) and yeast infections. Ear infections can also be very aggravating for pets.

Allergies

Pets may be allergic to airborne substances, foods, or parasites. Allergic reactions to foods or airborne allergens are more likely to make a pet itch on the ears, face, feet, and belly. Seasonal itching suggests an allergy to fleas, other insect bites, or pollen. Other possible allergens include natural food ingredients, artificial ingredients in cheap pet foods, cigarette smoke, dust, mold, and many other substances. Pets can even be allergic to plastic or rubber food dishes, developing acne-like sores on their lips and chins.

Pyotraumatic Dermatitis (Hot Spots)

This condition, characterized by itching, inflamed, oozy, raw skin, often afflicts dogs with thick long coats, especially those that have recently moved from cool to hot climates. The cause is not known for sure, though insect bites and false nerve stimulation are suspected. There are topical and injectable medications available to treat hot spots.

Hot spots are less common in cats, and when they occur, they usually result from stress.

Low-Fat Diet

Some cats on fat-reduced weight loss diets develop dry, itchy skin. Unlike omnivorous dogs and humans, cats are obligate carnivores, which means that they need fats to make up a higher proportion of their diet. For this reason, I recommend encouraging increased exercise and feeding a low-carb rather than low-fat diet to help cats lose weight (see How to Help Fat Cats Lose Weight for tips and advice).

Dogs don’t need as much fat in their diets as cats do. In dogs, itchy skin is more likely to be caused by allergies than dietary fat deficiency.

Emotional Problems

Stress, anxiety, boredom, and obsessive-compulsive disorder may cause a pet to scratch, bite, and generally overgroom his coat. In cats, the problem is called psychogenic alopecia; in dogs, it’s called acral lick dermatitis. High-strung, nervous individuals are more prone to this problem.

Take your pet in for a veterinary checkup before assuming that the problem is psychological.

Other Causes of Itchy Skin in Pets

Additional causes of itchy skin include syndromes that affect the immune system, cysts, tumours, embedded objects (i.e., a thorn), and reactions to medications or medical procedures.

How to Tell if There’s a Problem

All cats and dogs do some scratching and licking, and a little itching doesn’t necessarily signify a medical condition or infestation. Indications of parasites or medical issues include the following:

    • Bleeding
    • Crusty, scaly, or flaking skin
    • Foul odour on the skin
    • Hair loss
    • Interrupting play, eating, or sleeping to scratch or lick
    • Pus/oozing wet skin
    • Red skin
    • Scabs
    • Sores

In addition to these skin-related symptoms, general symptoms of illness such as vomiting or lethargy are also red flags.

Treatments for Itchy Skin in Cats and Dogs

Treatments for itchy skin in pets depend on the cause of the itching. Bacterial infections are treated with antibiotics, fungal infections with antifungals, and allergies with removal of the allergen if possible and steroid medication in some cases. Food allergies can be treated by implementing a hypoallergenic diet. In the case of sensitivities to unnatural ingredients, implementing a more natural diet free from artificial additives and preservatives can be beneficial.

Parasite infestations may require either topical or oral medications and/or special shampoos to eliminate the parasites. It’s also important to rid the home of parasites and eggs.

Essential fatty acids are often beneficial for pets with dry, itchy skin. Check with a veterinarian before administering supplements, and be sure to purchase supplements designed for pets rather than people. Your veterinarian may also recommend additional supplements.

Some owners have had luck with alternative treatments such as acupuncture, homeopathy, antioxidant therapy, and bathing with aloe vera and oatmeal products. Consult a veterinarian before using natural remedies.

If emotional factors are causing the problem, providing more time and attention, removing stressors whenever possible, providing an enriched environment for indoor cats, more chew toys and walks for dogs, and more playtime for both can be beneficial. Some owners find the use of calming pheromone products such as Feliway for cats and D.A.P. for dogs helpful.

Severe psychological problems that don’t respond to other interventions may require medication, though this should be considered a last resort because anti-anxiety and mood-altering medications have side effects and many are addictive.

For more cat articles, see the main Cats page. For more dog articles, see the main Dogs page.

This article is provided for informational purposes only and is not intended as a substitute for veterinary consultation and care.

References:

    • Barches, E., DVM. (2011). “Scratching or Licking the Skin (Itching) in Cats and Dogs.” DrBarchas.com.
    • Carlson, D., DVM, & Giffin, J.M., MD.  (2008). “Itchy Skin Diseases in Cats.” Pets.WebMD.com, Excerpted from the Cat Owner’s Home Veterinary Handbook.
    • Eldredge, D.M., DVM; Carlson, L.D., DVM; Carlson, D.G., DVM; & Giffin, J.M., MD. (2007). “Itchy Skin Diseases in Dogs,” Pets.WebMD.com, Excerpted from the Dog Owner’s Home Veterinary Handbook,
    • Feline Advisory Bureau. (n.d.). “The Itchy Cat: What to Do When It Is Not Fleas.” FABCats.org.
    • Healthy Pet Journal. (2007). “Alleviating Your Pet’s Itchy Skin.” HealthyPetJournal.com.
    • Hines, R., DVM, PhD. (2011). “Why Is My Cat or Dog Losing Its Hair? Hair Loss Problems in Cats and Dogs.” 2ndChance.info.
    • Messonier, S., DVM. (2007). “Questions for Dr. Shawn – Allergies, Steroids, Supplements, Fish Oil.” PetCareNaturally.com.
    • PetPlace Staff. (2011). “Itch, Itch, Itch – When Your Dog Can’t Stop Scratching” and “Itch, Itch, Itch – When Your Cat Can’t Stop Scratching.” PetPlace.com.
    • Veterinary & Aquatic Services Dept., Drs. Foster & Smith. (2011). “Trombiculiasis (Chiggers) in Cats.” PetEducation.com.

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