The things that cause human asthma are a common cause of scratching in dogs. Pollen, dust mites and household spores are often the cause of atopic dermatitis in dogs. These allergens cross your dog's skin barrier in the hairless regions such as the feet, the groin, the tummy and the arm pit. Dogs with atopic dermatitis have a deficient skin barrier with faulty ceramides. The skin loses moisture and allergens penetrate the skin initiating an allergic reaction.
Grass pollen is a common cause of atopic dermatitis as grasses are wind pollinated. Grass pollens are therefore very small so that they blow easily in the wind. Grass pollens blow in the wind and get everywhere making it almost impossible for atopic dogs to avoid them.
Tree pollens are much larger as many trees are insect pollinated and especially by bees. Tree pollens usually fall to the ground under trees and are a common cause of contact allergies which are predominantly on your dog's feet and ventral abdomen (tummy).
It has recently been proven that there are three different points of entry for pollen into the body which causes different antibody production depending on the route of entry of the pollen.
Due to a faulty skin barrier, most pollen actually crosses the skin barrier. This is called transdermal. Pollen is also inhaled by breathing in pollen in the air. Pollen is also ingested by dogs licking itchy feet and skin. As a consequence different antibody groups are stimulated giving rise to IgG and IgE. This is important for desensitisation. It is now recommended to have skin prick tests as well as blood tests for a more comprehensive picture of the full range of allergens.
Pollen is one of the many causes of allergic skin disease in dogs. For more information and to download a FREE "Self Diagnosis Manual to the Itchy Dog" visit http://www.scratchingdoghelp.com
