Skin Allergies in Dogs
With spring arriving we are starting to see more itchy dogs through the clinic doors. The main cause of this seasonal itch is allergy. Skin allergies can be divided into a number of causes including contact allergy, flea allergy, atopy and food allergy/intolerance. The main clinical sign of allergy is itchy skin leading to scratching, chewing, licking, rubbing or shaking of the affected skin. It is important to remember that the skin includes the ears, paws and anal glands.
As the name suggests this is caused by the irritating substance (allergen) being in contact with the dog’s skin. This leads to itching, inflammation and redness in the area that has been touched. Areas affected are usually the feet, and along the abdomen. Common causes are grass (especially fresh cut grass) and Wandering Dew. Management of contact allergy involves avoidance if possible and topical application of steroid based creams and ointments.
Flea Allergy (very common)
This is caused by an allergy to flea saliva which is injected into the blood when a flea bites. This leads to itching and hair loss typically around the tail base. In allergic dogs it only takes a small number of flea bites to cause a reaction so typically fleas are not seen despite the irritation they cause. Management of flea allergy involves strict all year round flea control and short courses of anti-itch medication to provide relief.
Atopy (very common)
Atopy is caused by an allergic reaction to environmental allergens e.g. pollens, moulds, dust mites. Clinical signs include itching and inflammation especially. involving the ears, inside the elbows and back legs. The underlying reason for these dog’s allergies is a genetic based weakness in the skin barrier allowing allergens to trigger an inflammatory response. Breeds commonly affected are Labradors, Boxers and Staffordshire terriers. Atopy typically starts in young dogs 2 – 4 years old and is usually seasonal in nature. Management of atopy involves avoidance of environmental allergens (if possible), regular shampooing, fatty acid (fish oil) supplementation and anti-itch/ anti-inflammatory medication.
Food allergy/ intolerance
This is caused by an allergy to an ingredient in the diet. Clinical signs include itch and inflammation often affecting the ears, paws and under the tail base. Common ingredients that trigger a reaction include beef, lamb, and pork products. This allergy is managed by avoiding the triggering ingredients, typically by feeding a chicken or fish based diet.
Many dogs have a combination of the allergy types above and the underlying causes combine together to produce an itch. This is known as the itch threshold. Managing and eliminating the causes that we can will often drop the allergens below the itch threshold and result in clinical improvement.
For example, consider a dog that has concurrent atopy and flea allergy. Even if we don’t know the trigger for the atopy the itch may be sufficiently managed by strict flea control. A dog with concurrent atopy and food intolerance may respond to dietary changes alone.
Unfortunately, there is no cure for allergic skin disease but there are a number of ways we can minimise its effects. Strict flea control, regular shampooing, fish oil supplementation and skin diets are the first step. When these don’t give the relief needed anti itch drugs like steroids and apoquel are used.
It is important to remember that dogs can itch for a number of reasons other than allergy and the first step in achieving a diagnosis, treatment and relief is giving us a call and booking a consultation with one of the veterinary team.