Allergic Contact Dermatitis: Does Your Dog Scratch Incessantly?
Drs. Foster & Smith Educational Staff

Excessive Scratching
Short bouts of scratching are normal and necessary for every dog. But excessive scratching - especially at the muzzle, paws, and other relatively hair-free areas - can indicate a problem. If your dog just won't stop scratching, he may be suffering from Allergic Contact Dermatitis (ACD) or Irritant Contact Dermatitis (ICD). These two similar conditions occur when skin overreacts to an environmental factor.

  Allergic Contact Dermatitis Irritant Contact Dermatitis
Caused by Specific molecules Noxious substances
Trigger examples Certain antibiotics applied to the
skin, nickel, rubber, wool, chemical dyes,
and carpet deodorizers
Irritants such as
poison ivy sap and road salt
Frequency Rare Common
Affects Typically adult dogs,
and only those with a hypersensitivity to the molecule;
requires multiple exposures before developing
Every dog who is exposed to the irritant;
commonly young, inquisitive dogs
Symptoms Irritation and itchy lesions (some blister-like)
on sparsely haired areas
(paws, abdomen, muzzle, and lips)
Same as those of ACD;
ulcers may also appear

If you believe your dog may have ACD or ICD, visit your veterinarian. He or she may recommend an exclusion trial, during which your dog must stay in an uncarpeted room and avoid grass. If your dog improves, your veterinarian will slowly introduce individual potential allergens to determine the culprit. Your veterinarian may also perform a "patch" test, applying a small amount of the suspected allergen to your dog's skin, then monitoring him 2-5 days for a reaction.

To best manage ACD or ICD, remove or restrict exposure to the allergen or contact irritant in your dog's environment. If that is not possible, give your dog a fatty acid supplement, antihistamines; Biotin, and bathe him with Itch Stop Shampoo. Work with your veterinarian to determine the best strategy for minimizing itching and keeping your dog comfortable.