Itchy skin is a very common problem in dogs and can have a number of different causes. A step wise approach is needed to eliminate possible causes one by one until a diagnosis is made and treatment initiated.
⟪ ITCHY SKIN ⟫
Fact Sheet
Some causes are easily eliminated and some require careful lifelong management.
Stepwise approach leads to a diagnosis
1. Flea bite allergy:
Some dogs are allergic to flea saliva. It is sometimes difficult to find fleas on dogs with a flea allergy, so an effective and consistent flea treatment is essential in eliminating this as a problem.
2. Parasitic skin diseases: Mange (mites) and lice
Your vet may do a skin scraping, take hair samples and look for the parasites under a microscope. Parasitic skin diseases are usually easily treated once a diagnosis is made.
3. Infectious diseases / Skin infections: Bacteria and/or yeasts
These can occur on their own or are often seen in allergic cases where they contribute to the itchiness. If these infections are present, they are treated with antibiotics and antifungals.
4. Food allergy:
A food allergy can cause itching in dogs from any age. It can be ruled in or out by doing an exclusion diet trial and then “treated” by eliminating the offending food allergen. An allergen is usually a protein that causes the body to react, leading to redness and itchiness. Food allergy causes itchiness around the face, inside the ears, the feet and on the tummy. If fleas, parasitic skin conditions or skin infections are ruled out, then your next step would be an exclusion diet trial.
Food allergy exclusion diet trial:
Your vet will prescribe a specific prescription food formulated for trial purposes. It is critical to the trial that no other food or treats are given for 8 to 10 weeks. The smallest treat or other food will invalidate the trial. The rationale is to remove all food sources that your dog would have been exposed to in the past which may have caused the itching, with only new novel proteins being fed. The exclusion diet will not show an immediate improvement and if successful the itchiness will decrease gradually over the 8 to 10 weeks.
The biggest stumbling block with a food allergy is owner compliance. Some owners are in the habit of giving treats, and feel sorry for their pet not getting a variety of foods. It is worth persevering as it is the easiest and in the long run, cheapest way of controlling a food allergy.
5. Atopy – Allergies to pollens, house dust mite and other environmental allergens:
If the conditions mentioned in steps 1 to 4 have been eliminated, your dog will fall into this broad category of skin disease. This is the most common cause of itchy skins and up to 50% of skin cases seen fall into this category. It is caused by environmental allergens such as pollens and house dust mites.
These allergens enter through an unhealthy skin barrier and cause inf inflammation in the body. This in turn causes itching and when scratched, causes further skin damage and so the issue worsens. Secondary infections often complicate the allergic reactions as mentioned before. Atopy typically causes itchiness for the first time in dogs from the age of 1 to 3 years and then for the rest of a dog’s life.
Environmental allergies are usually recurring, may be seasonal or non-seasonal and can be difficult to manage. There is no cure, and usually lifelong management is required, either ongoing or at times of the year when the problem resurfaces.
Management of an itchy/allergic dog
In the case of flea allergies, infections (parasitic, bacterial and yeasts) and food allergies the treatment is usually straight forward. If the cause is treated (flea treatment, antibiotics, antiparasitics, antifungals) the itching usually resolves.
Environmental allergies are more difficult to treat, as it is usually not possible to remove the cause and these cases usually require careful long term management for the rest of the dog’s life.
Management is usually a multipronged approach
1. Anti-inflammatory/Immunosuppressants:
This is the most common treatment and includes drugs such as cortisone and cyclosporine. Cortisone has an immediate effect and cyclosporine requires 4 to 6
weeks to control the inflammation, however they can have serious long-term side effects such as liver dysfunction and diabetes. These drugs should be used sparingly and not as a long-term solution.
2. Immunotherapy:
This is a type of desensitisation therapy which is used in select cases only. Success is varied and treatment is very expensive.
3. Antihistamines:
These are a safe long-term treatment for allergies. They have very little side effects compared to drugs like cortisone. Antihistamines are often used in conjunction with other treatments as long-term management as they are not very effective on their own.
4. Topical treatments:
These also include cortisone, antibiotic and anti-yeast treatments that come in the form of shampoos, creams and sprays. They don’t have the same side effects as tablet or injectable format and can be effective in localised areas.
5. Essential Fatty Acids (Omega-3 and 6):
These play a major role in managing the disease long-term. They strengthen the skin barrier which helps to protect against the environmental allergens as well as reduce inflammation. There are no side effects and over time can help to reduce the need for cortisone. The positive effects can take a month or two to be seen so it is important to keep your dogs on EFAs long-term.
Environmental allergies cannot be cured and are therefore a lifelong problem for which lifelong management is required. If treatment is stopped, the allergy will flare up and require high dosages of medication to bring it under control, whereas if treatment is ongoing, lower dosages of medication are required that are cheaper and safer in the long run. Allergies can be frustrating for owners. As depicted above, it is a lengthy process, but by working closely with your vet it can be rewarding.