02 4721 5494

22 Belmore Street, Penrith

Penrith Veterinary Hospital

Penrithvet

Cambridge vet answers the question, Why Is My Dog Itchy?

Most itchy dogs will show obvious signs like excessive scratching or chewing. However other signs – including paw licking, recurrent ear irritation, face rubbing, repeated skin infections (hot spots), scooting (dragging the bottom along the ground), chronic sneezing and weeping eyes – can also indicate your pet is itchy.

Furthermore, there are other causes for each of these signs, so it is important to have us give your pet a thorough clinical examination before suggesting any treatments.

There are two common reasons for dogs to be very itchy:

  1. Allergic skin disease, also called eczema, summer eczema, grass allergy, dermatitis and allergic dermatitis. This is a relatively common problem in dogs, with some breeds being more susceptible than others.
  2. A mite infestation called scabies which is often difficult to diagnose, and may require a treatment trial to eliminate the possibility. Based on factors like contact with an infected animal, the area of itchiness, skin scraping results and lack of response to other treatments, we will be able to advise you if a trial is necessary.

Allergic skin disease can be divided into five general categories:

  1. Flea allergy effected dogs are usually chewing or scratching at their tail-base or around the neck, but they can be itchy anywhere. Unfortunately it takes only one fl ea to cause a major irritation for a dog allergic to fleas, which is why some dogs that have very few fl eas can be itchier than a non-allergic dog with many fleas. While often a seasonal problem (Spring/Summer), fl ea allergy can occur yearround, particularly for inside pets. This is by far the most common type of skin allergy seen in dogs.
  2. Inhaled allergy (or atopy) is relatively common and generally effects all areas of your dog, including the paws, ears, and face. The most common allergens (a substance causing an allergy) are grass pollens, other plant pollens, dust mites and moulds (the latter two being found normally in indoor environments). While often seasonal initially, this allergy can progress to be a year-round problem.
  3. Contact allergy is quite uncommon, and usually effects areas with little of no hair covering, for instance the feet and abdomen. Allergens include grasses, plants, clothing/carpet fi bres, hessian bedding and many others. This is often a seasonal allergy, but can be year-round, depending on the cause. The most common cause is contact with Wandering Jew; an evergreen, small-leafed creeping plant.
  4. Food allergy often causes dogs to be itchy around the face, ears and feet – although they can be itchy all-over. The most common allergens are wheat (found in most canned and dry foods), beef and to a lesser degree, chicken. Food allergies will occur any time of the year that your pet is receiving the allergy inducing food.
  5. Allergy to bacteria normally found on the skin is also called a ‘Staph Allergy’, as Staphylococcus is the most common skin bacteria. This allergy will often cause slightly different signs to the other allergies, but we will be able to determine if this is a factor in your dog’s itchiness. This allergy can also be present year-round and is one which requires specific treatment from your vet.

While it is helpful to group skin allergies into these five groups, due to the similarity in signs, it is impossible to tell on appearances alone which allergen is causing the problem. The allergens mentioned above are the most common sources of irritation, but there are literally hundreds of substances which have been reported to cause allergies in dogs. As well, many allergic dogs are allergic to more than one allergen.

So where do we start?

Our goal is to identify a cause for your pet’s allergy

It is very helpful to follow the suggestions on this page, however it is most important to us that your pet isn’t suffering during this time.

If you have any questions, are unsure which approach is best to take, or if you are having no luck with these medications, please do not hesitate to call us.

A home prepared low-allergy diet should include the following ingredients:
  • Meat, which your dog hasn’t been fed before, such as fish (including tinned tuna in brine), kangaroo, rabbit or lamb. Approximately 30% of the meal.
  • Boiled rice, including the starch. Approximately 50% of the meal.
  • Raw or cooked vegetables, excluding onions. Approximately 20% of the meal.

Flea and food allergies can be ruled out without medications or expensive testing:

  1. If fleas are present it is worth trying to eliminate them. Unfortunately, where allergies are concerned, we need to eliminate all fl eas from the environment. This is difficult, but we can advise on the best fl ea treatments for your situation.
  2. If a food allergy is suspected, we can trial your pet on a low-allergy diet. This involves maintaining a special diet for 4–6 weeks and not deviating from a strict list of foods. For instance, giving a single dog biscuit at week 4 can ruin a trial in a dog allergic to wheat. This is difficult, but does help us greatly to identify a food allergy. Having eliminated food and flea allergies, an allergy test may then be suggested. (c)
  3. Allergy tests identify inhaled allergens, including plant, tree and grass pollens – as well as dust mites and moulds. We collect a small blood sample from your pet, and the results are available within 2 days. If the results suggest an allergen which cannot be avoided or eliminated, then a ‘desensitising’ vaccine is made up and given as a series of injections. A positive response is seen in approximately 50% of pets and side effects are uncommon.

If all of the above options have been performed to no avail, then a contact allergy or inhaled allergy not included in the allergy test, is most likely. Further trials can be performed at home, such as changing bedding or sending your dog to a friend’s house for 3–4 weeks. If a cause can still not be identified, a second option is appropriate.

Medication trials are also very useful, in consultation with one of our vets

  1. Cortisone is often used to control allergies, being the only medication that will nearly always stop itching quickly and effectively. This makes it a great short-term solution and as such, it may be prescribed for daily then alternate-day, morning dosing. However, due to side effects when used in high doses or for long periods, cortisone is not a good long-term solution. Side effects include liver problems, weight gain, increased risk of infection, diabetes, hair loss, lethargy and increased thirst. Some worthwhile alternatives used alone or in combination, are as follows:
  2. Cyclosporin is a medication that works as well as cortisone but has fewer long -term side effects. It is however relatively expensive, especially for large dogs.
  3. Other prescription medications are now available that have very few side effects and provide excellent long-term solutions, when effective. Unfortunately, not all itchy dogs respond to them equally, so we may advise a treatment trial.
  4. Antihistamines have drowsiness as their main side effect, which can be remedied by reducing the dose. The effectiveness of each antihistamine varies, even for each dog. For this reason we suggest trying at least three different antihistamines before deciding if this treatment will work for your pet. All can be purchased from the chemist without a prescription (refer to the adjacent table). Furthermore, antihistamines are up to 50% more effective when combined with a fatty acid supplement.
  5. Fatty acid supplements including Evening Primrose oil are widely available with little risk of side effects. Give 1–4 capsules in food a day, the higher dose for larger breeds. The capsules can also be broken, and the oil applied to food. An alternative supplement (Megaderm) is available from us and may prove more cost effective.
  6. Anti-allergy shampoos and conditioners available from us can be effective in providing at least short-term relief from itchiness (e.g. Epi-soothe and Aloveen). Other products have been reported to help (e.g. Tea Tree shampoos and eucalyptus rinses), but we have had rare allergic reactions reported with these products.

After examining your pet, we may also dispense other treatments such as antibiotics or Malaseb Antifungal Shampoo, to help relieve itchiness.