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Which itch?
The Dogtor is In
which itch

Here you will find my list of the most common causes of itchy skin and ears in dogs and cats, and some ways to prevent it. As always, this article is not a substitute for visiting your vet for diagnosis and treatment. 

By far and away, in southern Georgia, the most common reason for itchy skin or ears is allergy to the environment. The earth here seems to be a petri-dish for pollens, danders, allergens and parasites that cause itching. Signs of a seasonal/environmental allergy will include flair-ups in level of itch and presence of skin lesions like crusts and scabs during certain times of year or when moving to different regions of the country. The thinner haired area of the belly and armpits, as well as inner thighs, flanks, under the neck, ears, and muzzle may be affected. Waxing and waning symptoms and patterns of normalcy until certain weather changes are strongly suspicious for this type of skin sensitivity. You vet will likely prescribe an anti-itch or anti-allergy medication to help stop the current itch, but be aware that many pets need consistent treatment during challenging seasons. 

When examining your pet for pruritus (the medical word for “being itching”), your vet will check for the presence of ectoparasites such as fleas, ticks, and mites. The first question to answer is whether the itchy pet has had a flea prevention regularly applied, and if so, when was the last application? If fleas or mites are suspected or seen directly on the pet, or the pattern of hair loss and scabbing is consistent with areas likely to be affected by these creepy crawlies, that is the cause of itching until proven otherwise. Flea infestations are relatively simple to prevent, however a three-step approach is imperative to successful long-term control of flea problems. All pets living in the home and yard must be treated, the home must be treated, and the environment must be treated. If you skip a step, or lapse in prevention, you will have fleas, guaranteed. Keep in mind that treating fleas may not stop a pet’s flea bite hypersensitivity, which is the response that some pets experience to even a single flea bite. Treatment for ectoparasite infestation includes the use of a long-acting flea prevention (many of which also treat skin mites), and if needed, an anti-allergy medication (ex: corticosteroids, Apoquel, Cytopoint immunotherapeutic injection) to slow and stop the secondary itchy effects. 

When the presence of fleas is ruled out, the pet is checked for evidence of skin infection. On the belly and armpits this may look like pink or yellow crusty circles, raised red spots or pustules, red or pink skin, and signs of hair loss or skin abrasion from intense scratching. Crusty patches of cracked and dry skin with thickening, especially on the legs and feet or ear tips may be consistent with a fungal infection. Round patches of hair loss, commonly around the face, ears, and eyes may be caused by demodex mites or ringworm (a misnomer, as it is a fungus and not a worm). Careful assessment and microscopic examination of skin samples will allow your vet to diagnose one or more of these infections. Skin infections are best treated with a multi-systemic approach including topical therapy for localized lesions, and medicated shampoo or mousse treatments with oral antibiotics or antifungals for diffuse lesions. The duration of these treatments can be weeks or months for advanced infections, so take your pet to the vet at the first sign of skin trouble. 

Generalized and chronic inflammation and itching over the entire body, which may also involve the ears, feet, and even anal glands, can be indicative of seasonal or environmental allergy but may also be attributed to food allergies.  If cutaneous diet allergy is suspected and other causes of skin disease ruled out, a strict elimination diet trial will be recommended. A trial should take no less than 12 weeks, and the very best diet to use is a hydrolyzed or hypoallergenic formula. These are made in such a way that the protein structure of the food’s ingredients (the body’s over-reaction to certain proteins is the reason an allergy develops) are too small to incite an inflammatory response when ingested. 

A strict trial means that no other outside sources of protein should be ingested during the trial, as this tends to skew results. Prepare for no other treats, table scraps, or even flavored chews or heartworm preventatives to be orally administered during this time.  After the trial, if the itching is gone and skin is improved, a challenge is performed using a diet containing the suspected allergen-inducing protein. If the pet’s skin flairs up after ingestion, then that protein is the source of the allergy. If not, another protein source is selected for the challenge, or the pet may remain on the specialized diet which successfully allowed resolution of their symptoms. 

If a rather expensive and restrictive diet trial is not possible, then novel protein and limited ingredient diets may be tried. Novel protein diets use “novel” or non-commercial protein sources such as rabbit, duck, even kangaroo. Limited ingredient diets are strict in using just a few protein and carb sources in their formulation. Next time you are choosing a diet for your pet, read the ingredients list: there are often numerous protein sources added to derive the essential nutrients and preservatives used in commercially sold pet foods, which confuses interpretation of food allergy results. 

A proper diet trial followed by successful challenge period is the only way to truly diagnose a food allergy in your pet. 

This has been a short summary of a few common causes of itch in dogs and cats. Remember that you should always consult your veterinarian when trying to determine why your pet is scratching. Skin is our largest immune organ, and it is a complicated one. 

There are as many therapies as diseases of this organ, and for your pet’s comfort and your peace of mind, act quickly when the itching starts.