Atopic dermatitis in Dogs
Is there anything worse than seeing an animal scratching and itching at sore skin? At Pet Prescription, we know these things cannot be helped, especially with skin issues like atopic dermatitis or atopy. If your dog suffers from a skin disease and you’re at your wits end with managing the ailment, read on to find out what the key factors of atopic dermatitis are, its causes and the treatments available to keep the condition under control.
Atopic dermatitis or atopy is a common skin condition similar to eczema. The condition is mostly seen in dogs who have inherited the tendency of allergic skin disease. Atopy develops in young dogs usually between 6 months and 3 years old and is very unlikely to develop in dogs over 7 years of age.
Atopic dermatitis in dogs is often caused by genetics and means their immune system is oversensitive and is overreacting to certain allergy-causing substances, like certain foods, pollens or house dust mites. When exposed to the allergens, the immune cells involved in allergies release compounds such as histamine into the body which causes the dog to itch, otherwise known as pruritus.
Seasonal changes play a huge role in our skin as well as our own pet’s skin. For instance, during the summer months, your dog could be affected by environmental factors like the increased pollen count. Warmer temperature also increases the chance of picking up some pesky fleas, which will undoubtedly cause irritation to their skin. You’d expect the winter months to create some respite for our four-legged friends but unfortunately, when the winter rolls back around and the central heating is turned up, your pooch could fall victim to dust mites in old central heating units.
The main sign associated with atopic dermatitis is pruritus. Pruritus is the medical term used to describe that itching, unpleasant sensation of the skin. You may notice your dog licking or chewing themselves excessively, rubbing themselves on the floor, furniture or grooming themselves more than usual. These behaviours may lead to patches of hair loss, red, sore and flaky skin. You may also notice them shaking their heads and pawing at their ears. If the skin within the ears is red and irritated - this could indicate that mites or pollen are causing irritation inside the ear. So, make a habit of checking and cleaning their ears as part of their grooming regime. Other commonly affected areas of the body include the face, feet, chest area, stomach and groin.
Long term or reoccurring skin disease such as atopic dermatitis can cause chronic changes in the skin and hair coat. You may notice saliva staining from the excessive licking or chewing and the skin itself becomes thickened (lichenified) and dark in colour (hyperpigmented). Up to 65% of cases are complicated by secondary skin infections called pyoderma, which is the medical term for a bacterial infection of the skin. This will display with sore pustules, reddened, raised and crusty skin. This will effectively affect another layer of skin, causing even further discomfort and pain for your dog.
When you first visit your vet, atopic dermatitis will not necessarily be the initial diagnosis. Atopy is not simple to diagnose and can be a long and involved process requiring commitment from both the vet and the owner to reach a definitive diagnosis. It is essentially a process of elimination meaning that the other causes of allergic skin issues need to be ruled out before atopic dermatitis can be diagnosed. Once your vet is suspicious of atopic dermatitis, they will need to perform a series of tests to rule out the potential other causes of allergic skin disease. Here’s a list of recommendations that your vet may suggest to you:
- Regularly apply a flea treatment. Though flea bites will not be the cause of your dog's atopy, it will certainly exacerbate their condition. If their condition improves, it may indicate a flea infestation rather than a genetic skin problem. Many pets suffer from flea allergy dermatitis, more commonly referred to as FAD.
- To relieve itching and sore skin. Your vet may recommend using a combination of shampoos, supplements and a course of oral antibiotics lasting at least 3 weeks.
- To speed up the diagnosis, your vet may request samples of the affected areas of skin. Moulted fur taken from their grooming brush will most likely suffice. The sample will be examined for mites, yeasts, bacteria and fungi. Blood samples may also be taken to look for the presence of the mite Sarcoptes scabeii which causes intensely pruritic mange.
- The next step is to perform a food trial to see if your dog is allergic to certain foods. Animals on food trials are fed specifically formulated diets such as Royal Canin Anallergenic or Hypoallergenic diets for a minimum of 6 weeks. It is very important that they are not fed anything else during the food trial, no treats or titbits, only the special diet.
Food intolerances are rare. Testing for them is often seen as the last resort so if the skin disease hasn’t improved whilst on a recommended diet then a diagnosis of atopic dermatitis will most likely be made. At this stage, it is possible to do another, more rigorous skin test on the dog to determine what allergens are causing the reaction. This is done by clipping a patch of hair on the flank and injecting small amounts allergens under the skin and comparing the reactions around the injection sites after 15 minutes.
Essential Fatty Acids (E.F.A’s): Essential Fatty Acids are present in supplements such as Viacutan, Coatex, Yumega and Gomega. Some of the E.F.A’s that play a pivotal role in improving skin conditions are Omega-3’s from fish and nut sources and linolenic acid which is a plant oil extract. These ingredients help to stabilise the skin and improve skin and hair coat quality. They are very beneficial in a wide variety of skin problems including atopy.
Antihistamines: These reduce the histamine which is causing the irritation and can work well in conjunction with E.F.A’s. They can improve around 25% of a dog’s allergy issues. There are no veterinary specific products on the market but human preparations are used.
Steroids: Atopic dermatitis is a steroid-responsive disease and oral tablets of steroids such as prednisolone will relieve the pruritus but can have side effects such as increased thirst and appetite in the short term and can have potential effects on the liver in the long term.
Immunotherapy: Vaccines can be made according to the results of the skin tests described above. Depending on the allergens your dog reacts to, a solution containing small quantities is injected under the skin. This is a common procedure for humans as well as animals and over time the immune system regulates so the body doesn’t overreact to exposure of the allergen. It can take several months to have an effect and can improve up to 60% of atopic dermatitis cases but additional medications may still be needed to completely control the atopy and keep the dog as comfortable as possible.
Immunomodulation: A product called Atopica is available to treat atopic dermatitis and consists of soft capsules containing the drug cyclosporine. Atopica targets the specific cells in the immune system involved in allergies and modifies their response, again aiming to reduce the body’s reaction when exposed to the allergens. Atopica has fewer side effects than steroids as its action is more specifically targeted and doesn’t affect other organ systems as steroids can do. Occasionally, it can cause temporary vomiting or diarrhoea when treatment is first started but is usually resolved without having to stop the medication. Atopica is initially given daily but the dose can be tapered if the response to treatment is good. Atopica is available in various strengths and the exact dose required by your dog will be decided by your vet. Atopica is a prescription only medication which your vet will need to prescribe your dog before you can purchase it.