The four main causes of skin allergies in dogs

The skin is the largest organ in the body and so it is not entirely surprising that skin diseases account for a significant proportion of visits to both doctors and vets. There are many conditions that affect the skin of dogs, ranging from flea bites to skin cancer, but what is almost certainly the most important canine skin disease is atopic dermatitis.

Skin allergies are incredibly common in dogs, and whilst most cases are relatively mild and cause only minor irritation, dermatitis can cause significant long term suffering to affected animals. The most common manifestations of skin allergies are itching (or pruritus as it is known to vets), red and inflamed skin, fur loss and saliva staining, foot chewing and in long-standing cases, secondary symptoms such as the blackening and the thickening of skin.

The main causes of skin allergies in dogs are – atopy (allergies to things that are breathed in), food allergies and contact allergies, including flea allergies.

Atopic allergies are the most common (in my experience they account for at least 70% of cases of allergic dermatitis in dogs) and are caused by allergic reactions to inhaled allergens such as pollen from trees and grass, which tends to be around for a few weeks at a particular time of year.

Other inhaled allergens - such as mould spores, house dust mites, chemicals on furniture and carpets, indoor air fresheners and fabrics like wool and nylon - can be a problem all year round.

Whereas in people these allergens would usually lead to hay fever symptoms such as sneezing and red eyes, in dogs the symptoms tend to be expressed in the skin, and licking feet and generalised itching are the classic symptoms of a case of atopic allergy.

Atopy is more common in certain breeds, with small breed dogs such as Westies being most commonly affected – although all breeds can suffer from this kind of allergy.

The next cause of skin allergies is food allergies, although these are much less common than many people think and there is much debate over their true prevalence. Some vets are convinced that certain food ingredients such as wheat, beef and soya are responsible for a significant number of cases of skin allergies in dogs, but I think nowadays the consensus is that true skin allergies directly caused by food are actually quite uncommon. Having said that there is no doubt that they do occur, and feeding a hypoallergenic food (such as Vets Kitchen) is a good idea for any dog with a skin allergy as a precaution. See Dogs With Food Allergies.

Contact allergies, such as those caused by washing powders, grass and so on, are even less common than food allergies, but do need to be considered in dogs which have unusual patterns of allergies, such as redness only on the belly that has appeared just after their bed has been washed for example.

Flea allergies in dogs are another type of allergy that could be considered as a contact allergy, where direct contact with the saliva of the flea leads to irritation and skin disease. Find out how to check your dog for fleas and about natural flea control here.

Treating skin allergies in dogs is never easy and can often be a lifelong battle. Unfortunately, with the possible exception of desensitising ‘vaccines ‘ which are rarely 100% effective, there is no cure for most of these allergies other than avoidance of the cause, so long term symptomatic treatment is usually required.