Canine Atopy

If you have been given this handout it is likely that the vet suspects your dog of having Atopy. Skin complaints account for up to 25% of small animal consultations. The two most common causes of skin disease in dogs are Flea Allergy Dermatitis (FAD) and Atopy. Food allergies only account for a very small percentage of total skin allergies in dogs. Unlike humans, dogs do not display hay fever when exposed to pollens etc. Instead dogs display their allergies in the form of dermatitis.

What is Atopy?

Atopy is an allergic reaction of the skin to environmental particles. This allergic reaction leads to inflammation of the skin causing itchiness. Atopy can also manifest as infection or itchiness of the ears. The condition occurs when particles in the environment, for example – pollens, dust mites, spores etc land on the dog’s skin.

Your dog’s immune system overreacts to these particles leading to inflammation of the skin and subsequent itchiness. The scratching caused by this itchiness can damage the skin and allow bacteria to penetrate leading to infection. The commonly affected areas include the face, ears, feet and groin. In long-term cases there can be hairloss, skin thickening and pigment changes.

Why do some dogs get Atopy?

75% of atopic dogs will show signs before 3 years of age and some even as young as 3 months. Some breeds are more susceptible than others ie. German Shepherds, Staffordshire Terriers, Maltese, Shih Tzu, Cavalier King Charles, West Highland Terriers…and the list goes on!

Diagnosis

Diagnosis is difficult as there is no specific test for the condition.
Atopy is suspected based on:

• History
• The signs exhibited by the dog
• The dog’s age
• The dog’s breed

Allergy testing

Skin testing – Performed by veterinary dermatologist (specialist)
Series of injections of possible allergens (compounds that cause an allergy) into skin
Detects reactions in the skin

Blood testing – not as sensitive as skin testing but can be helpful.

Treatment

It is important to know there is no cure for this skin condition. In most cases it is impossible to minimize exposure to the suspected causes as they often multiple. Management is the key to success to minimize discomfort in atopic patients.

Corticosteroids eg Prednisolone. These drugs act to suppress the inflammation and reduce the itchiness. This in turn will help reduce the secondary damage caused to the skin from scratching. Fortunately dogs and cats aren’t as susceptible to the side effects of cortisone as humans are. However, they may cause increased water consumption, increased urination, weight gain, and may predispose to conditions such as pancreatitis, diabetes and Cushings disease with high dose, long-term usage.

• Antihistamines. Aid by reducing the allergic reaction of the skin. Used alone they have a poor success rate, so are often combined with other treatments. Unfortunately the same antihistamine fails to work consistently in all dogs; therefore various types can often be trialled on the one case. Examples include: Claratyne, Zyrtec, Periactin, Atarax.
• Antibiotics. Bacteria are often introduced into the skin from damage caused by scratching. Infections themselves will cause more itchiness and the story goes on… In such cases the vet may prescribe a long course of antibiotics to eliminate this infection.
• Shampoos. Shampooing your dog with an appropriate shampoo can be an effective way of alleviating symptoms. The bathing process removes foreign particles (allergens) and debris from your dog’s skin. There are a multitude of shampoos available each designed for various scenarios. Examples include Malaseb, Pyohex, Aloveen, Sebolyse, Episoothe and Pyoben. The staff can advise you on the correct shampoo for your dog.
• Essential Fatty Acids ie. Omega 3 and Omega 6 Fatty Acids. These are oils that can be added to the diet to help reduce inflammation. They act by directly inhibiting the body’s factors that are required for inflammation. In many cases they can significantly reduce the amount of corticosteroids used. This adjunctive treatment often takes a minimum of 3 weeks (and up to 3 months) before reaching optimum effect. Below is a combination that provides a good range of the essential fatty acids:
  • Fish Oil (cold water marine – not cod liver oil) – 1000mg capsule / 10kg dog plus
  • Sunflower or Safflower Oil – 1 tablespoon / 10kg plus
  • Evening Primrose Oil – 1000mg capsule / 10kg

It is important to remember that oils contain a large amount of calories so your dog’s diet should be adjusted to avoid weight gain.

• Desensitization. Specialist veterinary dermatologists offer a treatment aimed at reducing your pet’s allergies. It involves first determining what your pet is allergic to by performing intradermal skin testing (as mentioned previously). A custom “vaccine” is produced and a series of injections over months are given aimed at reducing the allergic reaction. It is most successful in severe atopic cases.
• Cyclosporine. This is a drug that acts to specifically target the immune cells involved in the allergic response without the side effects associated with cortisone. It requires daily dosing for a minimum of 4 – 6 weeks. Unfortunately it can be quite costly in larger patients.
• Ear medications. The ear canal consists of skin all the way to the eardrum. Therefore ear infections are very common in atopic dogs. The vet may prescribe eardrops and ear cleaning solutions in these cases.
• Flea Prevention. It is essential that dogs with atopy have effective flea protection. One flea bite maybe enough to cause to an intense allergic reaction in a dog suffering from atopy. In our opinion the only reliable flea prevention in dogs are Advantage, Advocate, Frontline and Revolution.

For further information canine atopy please don’t hesitate to phone the clinic on 5623 4822.