Why is my dog scratching?
A dog that is itchy and constantly scratching and licking himself is a source of irritation to many pet owners. The most commonly presented patient to veterinarians, especially in summer, is the itchy dog. Itches are almost invariably caused by an allergic reaction to something.
An allergy is in an unpleasant reaction caused by exposure to a food, inhalant, or something in the dog’s environment. What the dog is exposed to is called the allergen. The way in which the dog’s immune system responds to the allergen is the allergic or hypersensitivity reaction.
While humans tend to experience upper respiratory symptoms when an allergy is triggered, the target organ in dogs is usually the skin, with intense itching being the principal sign.
Canine allergies fall into four categories:
- Those caused by fleas and other biting insects (flea allergy dermatitis)
- Those caused by inhaled allergens such as dust mites, grasses, moulds, and tree and weed pollens (canine atopy)
- Those caused and by foods and drugs (food allergies)
- Those caused by irritants that have direct contact with the skin (contact allergies)
Skin allergies in dogs have a cumulative effect. Allergic dogs may do well when only one of the allergens they are sensitive to is present in the environment. However, when another allergen is added, the dog’s tolerance level may be surpassed and itchiness may occur.
As a result of the cumulative nature of allergic skin disease in dogs, it is advisable to prevent exposure to allergens whenever possible. To that effect, flea prevention and control becomes extremely important in managing the allergic dog.
The cause of the irritation can be frustratingly difficult to determine in many cases, but here are a few pointers.
Ear infection/irritation If your dog can’t seem to stop scratching an ear, ask your veterinarian to check for a yeast infection. Symptoms include irritated, itchy, or discoloured skin. The infection usually manifests in the ears because yeasts flourish in dark damp places like inside your dog’s ears. Yeast infections are easy to diagnose and often respond well to an ear ointment. Very often you need to treat your dog’s ears often, even when they do not seem to be worrying him, in order to permanently control the yeasts in his ears.
Superficial bacterial folliculitis is an infection that causes sores, bumps, and scabs on the skin. These skin abnormalities are easier to see in shorthaired dogs. In longhaired dogs, the most obvious symptoms may be a dull coat and shedding with scaly skin underneath. Folliculitis often occurs in conjunction with other skin problems, such as mange, allergies, or injury. Treatment may include oral antibiotics and antibacterial ointments or shampoos.
My dog has mange!
Mange is a skin disorder caused by tiny parasites called mites. This is a far more common condition in rural rather than urban areas. Many owners wrongly attribute their dog’s scratching to mange. Sarcoptic mange, also known as canine scabies, spreads easily among dogs and can also be transmitted to people. The symptoms are intense itching, red skin, sores, and hair loss. A dog’s ears, face and legs are most commonly affected. Demodectic mange can cause bald spots, scabbing, and sores, but it is not contagious between animals or people. Today mange is quite easily treated with a product such as Revolution or Advocate depending on the type of mange.
Fleas are tiny parasites on dog’s skin. Unlike ticks (pictured below) that tend to remain in one place, fleas will race around on the dog’s body especially if they are disturbed. They are one of the most common causes of itching in summer.
You may not see the tiny insects themselves, but flea droppings (visible as small black specks) are usually visible in a dog’s coat. Severe flea infestations can cause blood loss and anaemia, and even expose your dog to other parasites, such as tapeworms (use a deworming such as drontal, triworm or quantel which is effective against this tapeworm). Treatment may include a “spot-on” (Frontline, fiprotec, advocate etc.) and/or oral flea killer (capstar) and a thorough cleaning of the pet’s home area (Ultrum spray). The latter is important as only ten per cent of fleas are on the dogs at any one time; the remainder (including immature stages and eggs) contaminate the environment with a reservoir of fleas ready to repopulate your pet any time you slack off on the flea treatment! A flea problem often takes months to resolve even with resolute anti-flea treatment.
Ticks generally do not cause itching although their bites can cause some irritation. Their greatest danger is transmission of diseases such as Babesiosis (Tick bite fever, Biliary) in dogs. Most spot-ons and dips that control fleas control ticks. Whenever using any tick and flea product please follow instructions carefully.
Acral Lick Granuloma
Also called acral lick dermatitis, this is a frustrating skin condition caused by compulsive, relentless licking of a single area – most often on the lower parts of the legs. The area is unable to heal, and the resulting pain and itching can lead the dog to keep licking the same spot. Treatment includes discouraging the dog from licking, either by using a bad-tasting topical solution or an Elizabethan collar.
Hot spots, also called acute moist dermatitis, are small areas that appear red, irritated, and inflamed. They are most commonly found on a dog’s head, hips, or chest, and often feel hot to the touch. Hot spots can result from a wide range of conditions, including infections, allergies, insect bites, or excessive licking and chewing. This condition occurs most frequently in summer and in dog breeds with dense coats such as German Shepherds, Rottweilers, Chows and Retrievers. The most important part of the treatment is trimming, or even shaving, off the hair over the area to allow air to circulate and dry the area. Hot spots need to be treated as soon as possible to limit their spread – in severe cases very large areas of skin can become affected.
Anal Sac Disease
This is the most common reason for an itchy bottom in dogs. Dogs have small anal sacs (at 4 and 8 o’clock to the anus), which can become impacted if they don’t empty properly. The hallmark of impacted anal sacs is a dog scooting his bottom along the ground. Other symptoms include biting or licking the anal area. A vet can manually express full anal sacs, but in severe cases, the sacs may be surgically removed.
Medications commonly used in dogs with skin allergies include:
- Cortisone products such as prednisolone. These medications are not without side effects so they need to be used judiciously in treating skin allergies. Your pet will require regular check-ups if on cortisone.
- This is a medication which seems to be fairly effective at reducing the inflammation associated with skin allergies and calming the immune system of the affected dog. However, it is extremely pricey.
- These medications tend to have a variable effect when used in dogs. For some allergic dogs, antihistamines work very well in controlling symptoms of allergic skin disease. For other dogs, very little effect is seen. However, antihistamines are considered to be worth trying in most cases since the side effects associated with antihistamines are minimal and they are less expensive.
Fatty acid supplements.
- Fatty acid supplements work by improving the overall health of the skin.
Antibiotics which are frequently needed to treat secondary skin infections.
Anti-fungal medications which are frequently needed to treat secondary yeast infections.
Hyposensitisation or “Allergy Shots” in Dogs with Skin Allergies
Hyposensitisation involves testing to determine to which allergens the dog is most sensitive and then introducing those allergens to the dog in ever-increasing dosages to desensitise the dog’s immune system to the allergen.
Hyposensatzation has its limitations in that not every allergen can be tested and the allergens to which your dog is most sensitive may not be included in the test panel. (Although as we have seen above, reducing the number of allergens to which your pet reacts may bring the reaction to below the allergic threshold which results in less itching.)
Hypo-Allergenic Foods in Dogs with Skin Allergies Many dogs with skin allergies suffer from food allergies. Therefore, dietary control can play a role in controlling the allergic skin disease.
Diets used in treating skin allergies in dogs are typically novel protein diets or hydrolysed protein diets. Novel protein diets (Hills d/d salmon & rice or Hills d/d duck & rice) attempt to introduce a food with a protein source that the dog is not likely to have eaten previously, in an attempt to avoid foods which may produce allergic reactions within the dog’s skin. Hydrolysed diets are the result of a special process rendering the normal protein unable to elicit an allergic response. All of these diets also usually contain higher levels of fatty acids and other ingredients to help prevent itching.
Help, he is losing hair!
Shedding and Hair Loss (Alopecia)Anyone who shares their home with dogs knows that they shed. How much shedding is normal depends on breed, time of year, and environment. Especially in early summer most dogs normally lose a considerable amount of hair, but sometimes stress, poor nutrition, or illness can cause a dog to lose more hair than usual. Generally you do not have anything to worry about unless there is excessive thinning of the hair coat or patches of hair loss.In the picture below, this dog is losing hair because of excessive scratching causing a bald inflamed area. Hair loss without evidence of itching or scratching is unlikely to be allergies or parasites such as fleas. Hormonal imbalances are an important cause of hair loss without the itch.