My Pet Won't Stop Chewing, Scratching, and Licking His Skin. What's Going On?

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Licking, chewing, scratching, and self-biting are common symptoms in pets. Cats will lick excessively, sometimes biting out their fur in clumps or excoriating the skin about the head and face with their claws. Dogs will scratch repetitively with their paws or gnaw incessantly; target areas can include the whole body, or specific areas, like the backside, legs, and feet. Regardless of the form of the symptoms, when they appear in excess, they point to one thing: itchiness.

Known as pruritus in medical terms, itchiness is among the top reasons owners take their pets to veterinarians. To fix the problem, a vet must find the root of the problem. And that’s often a tricky prospect.

Causes

There are a variety of causes for itchiness in pets.

1. Allergic skin disease. This is perhaps the most common cause of chronic or seasonal itchiness in pets. The typical cycle in both dogs and cats goes like this: in response to an allergen that’s been inhaled, absorbed, contacted, injected (by an insect, for example), or eaten, pets can display skin symptoms such as rashes, scabs, pustules, ear infections, backside rubbing, and just plain scratching — sometimes in one location, sometimes all over. And itchiness, as we all know, begets skin trauma, inflammation, and infection.

Yeast and bacteria love the warmth and moisture afforded by the resulting inflammation and will grow happily in this milieu. These organisms and their detritus elicit even greater inflammation and itchiness — and sometimes even an additional allergic response.

2. Yeast (malassezia) infection. Yeast infections are notoriously itchy. But almost all yeast infections in pets are secondary to allergic skin disease. Still, it bears mentioning that once in a while pets who are not suffering allergies can get yeast infections.

3. Fleas. These insects are an extremely common cause of itching. By themselves flea bites are itchy enough, but when a pet is allergic to flea bites, even a tiny amount of flea saliva can send a pet into a squirming paroxysm of pruritus for weeks.

4. Ringworm infection: Not a worm at all, this fungal infection is called dermatophytosis. And it can be very itchy for some pets.

5. Mites and other creepy crawlies. Mange mites can be extremely itchy beasties. There are a few different types of mange mites. They can live on the surface of the skin or burrow deep into pores and follicles. Different species tend to infest dogs and cats, but the result is often the same: pruritus. Lice can also cause itchiness, but these are lower on the list when it comes to frequency of occurrence and itch potential.

6. Bacterial infections. As it does with yeast, animal skin can get really unhappy in the presence of bacteria. Allergic skin disease is the No. 1 cause of chronic bacterial skin infections in dogs and cats.

7. Nonskin diseases. Plenty of systemic diseases can manifest in the skin and cause itching. These include hypothyroidism in dogs, autoimmune diseases, and psychogenic/behavioral disorders.

What To Do at Home

There are some steps pet owners can take at home to help keep the itchies under control.

1. Use external parasite preventives if you live in areas prone to them. Make sure you are using products that are approved for your pet (don't use dog products on cats, for example). Ask your veterinarian to recommend the best products for your pets.

2. Bathe your pet if he seems itchy. There are shampoos available to help soothe irritation, fight infection, and relieve pruritus. It’s important, however, to consult your veterinarian about the best product to use. And never use human products on your pet unless your veterinarian advises it.

3. Try sprays and powders. Safe, effective topical therapies are available. Ask your veterinarian for a recommendation.

4. Keep pets well groomed. Excessive or unkempt hair can lead to irritation, infection, and itchiness. Matted fur can also help mask fleas and other evidence of skin problems.

5. See your veterinarian at the first sign of discomfort. If your pet is licking, pawing, scratching, or biting himself, take him to the vet. Early intervention is often the key to successful treatment.

What Your Veterinarian Will Do

When you take your pet to the vet for itchiness, procedures and recommendations may include the following:

1. History. Most veterinarians will start by asking a few questions to understand the history of the problem. When did you first notice the itching? Has it changed? How has your pet been otherwise? What do you normally do to take care of your pet’s skin? What medications or products do you use? Take these products with you so your veterinarian can see them (and so you don’t forget).

2. Physical examination. Giving the whole body, not just the skin, a thorough look is a crucial part of the process. When examining the skin itself, your veterinarian will check for the presence of lesions (bald areas, rashes, redness, pustules, scratches, etc.) and evidence of external parasites.

3. Skin scrape. Scraping the very surface of the skin with a metal scalpel blade and examining the cells under a microscope can help your veterinarian determine whether mites might be living just beneath the surface of the skin.

4. Impression smear. Examining collections of cells and debris found on the surface of the skin (or within a lesion) is a common practice. Evaluating these under a microscope can tell your veterinarian whether microscopic parasites and/or bacteria and yeast are involved in the itchiness.

5. Culture and sensitivity. Once a bacterial organism has been identified (or is assumed based on the characteristics of the skin problem), culturing the skin (usually of a pustule or other lesion) is standard procedure. This tells your veterinarian what kind of bacteria live there and which antibiotic will best defeat it.

6. Biopsy. It may sometimes be necessary to obtain a small sample of skin tissue and submit it to a diagnostic laboratory to determine its condition before definitive treatment can be initiated.

7. Food trials. If your vet suspects your pet may have a food allergy, a food trial may be recommended. Eliminating all but a few ingredients in a pet’s diet for a period of time can help isolate which proteins a pet may be allergic to.

8. Allergy testing. Allergy testing may be recommended, especially for pets that may have allergies to inhaled allergens. Sophisticated skin or blood testing can help determine which allergens a pet might be reacting to.

9. Fungal culture. Should a fungus be suspected, the affected hairs can be sampled for culture testing.

Treatment

Treatment of itchiness depends wholly on the underlying cause. It can range from topical or oral medication to kill parasites to thyroid hormone supplementation to long-term allergy treatment, in which a multipronged approach involving oral and/or topical therapy (at least in the short term) along with restricted diets and/or immunotherapy may be prescribed.

This article was written by a Veterinarian.

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