Nick Tremlett

Skin Allergen Test

One of the problems I am seeing on an increasing basis is itchy dogs due to skin allergies. These dogs get referred to me once the usual suspects of fleas and other parasites have been dealt with. In the same way allergies in children are becoming more common, the incidence in dogs is also on the increase. Of the various things I find dogs reacting to, House Dust Mites (HDM) are by far the most common. This also mirrors what has been happening in children.

There are various species of HDM, but they generally all live in the fibres of our soft furnishings and carpets. When they die, either naturally or after the fabric is washed, they disintegrate over time and the particles that result make up the dust to which dogs and people become allergic. An illustration of the presence of dust in any house is seen on the surface of the TV screen.

The particles which make up the dust are small enough to enter the body, either by being breathed into the lungs, or being absorbed into the skin surface. The immune system then recognises the foreign material and reacts to it. Over a period of time this reaction becomes exaggerated to the point of becoming an allergy. This is when the response by the immune system is to cause inflammation and irritation. In children the consequence is asthma, and in dogs it is an intensely itchy skin.

Various drugs can be used to treat these allergies but over the last few years the trend has been away from drugs and more towards understanding the nature of the allergy and reducing the exposure to the allergens. In recent years the use of ‘desensitisation’ has also become a recognised control measure. This is a way of reducing the dogs sensitivity to an allergen, and as a result the itchy reaction to it.

The key to this approach is to identify what allergens we are dealing with and to this end we can carry out a skin test. The test involves injecting small quantities of the various possible allergens in to the skin and watching for a reaction. The reaction takes just a few minutes, and in most cases gives us a very clear indication to what an individual dog is allergic. You will see in the picture that Rocky has a clear reaction to several allergens, and turned out to be allergic to HDM and also mosquitoes. With this information we have now been able to control Rocky’s allergy by desensitising him to HDM and by making sure he goes for walks in areas where they are few mosquitoes.

Allergies may be an ever increasing problem but our understanding of them is growing too. If you think your dog may have an allergy problem don’t be afraid of seeking your vet’s advice. We can do more about it than you may think – and your dog will certainly be grateful!

by  Nick Tremlett MA VETMB MRCVS  Partner Kynoch Vets Wokingham