|Posted on October 5, 2012 at 2:20 AM|
Allergic contact dermatitis is a rare disease, which occurs when an animal's skin overreacts to certain small molecules in the environment. Substances, which can cause allergic contact dermatitis include certain antibiotics applied to the skin; metals such as nickel; materials such as rubber or wool; and chemicals such as dyes and carpet deodorizers.
Irritant contact dermatitis occurs when the skin is exposed to severely irritating chemicals such as the sap in poison ivy and salt on the road.
Allergic contact dermatitis only affects those animals with a hypersensitivity to the molecule. Irritant contact dermatitis would affect every dog that is exposed to the irritant.
Allergic dermatitis requires multiple exposures to the molecule before it develops. It rarely occurs in animals less than two years old. Irritant contact dermatitis often occurs in inquisitive young animals who get into things they should not.
Lesions generally occur on the areas of skin that are sparsely haired and directly exposed to the offending molecules. This often means the back of the paws, abdomen, muzzle, and lips. The affected areas are very red, have small bumps or vesicles (blister-like lesions), and itch. In irritant contact dermatitis ulcers may appear.
The history and physical exam can often indicate what is going on. To isolate the allergen (molecule that caused the dermatitis), exclusion trials are often performed. In these trials, the animal is restricted to an uncarpeted room and kept off the grass, for instance. If the animal's condition improves, potential allergens are slowly introduced one by one.
A 'patch' test can also be performed. In this test, a small amount of the allergen is rubbed on the skin, or a gauze pad containing the suspected allergen is bandaged on the pet's skin. The skin is monitored for 2-5 days for a reaction.
The key to managing this condition is removing or restricting exposure to the allergen or contact irritant in the pet's environment. If that is not possible, then fatty acids, antihistamines, biotin, and topical shampoos can be used to control the itching.
Categories: Allergies in dogs