Allergic Dermatitis in Dogs

Allergic dermatitis is a general term to describe a group of skin allergies that may be caused by a multitude of factors in dogs.

Allergies are immune reactions to a given substance (allergen), which the body recognizes as foreign. These reactions occur following initial exposure to the allergen, with subsequent development of a hypersensitivity that causes itching and inflammation upon future exposures.

The most common classes of allergic dermatitis seen in dogs are:

Flea bite allergy 

Food allergy 

Atopy – an allergic condition caused by inhaled allergens, or absorption of allergens through the skin

Less common are:

Drug reactions

Hormonal allergies 

Bacterial allergies

Allergies to other parasites (mites, intestinal worms, ticks)

Contact allergies (due to topical treatments or exposure to fibers, floor polish and detergents)

Atopy and flea bite allergy are usually seen in young adults, whereas food allergy can be seen at any age. There are a number of canine breeds predisposed to the development of atopy. And some animals may be prone to development of certain allergies due to genetic factors. Allergic signs may be seasonal, depending on the cause of the allergy.

What to Watch for

Scratching, licking, chewing or biting the skin, feet and ears.

Red, raised, scaly areas on the skin

Bumps, crusts or pus filled vesicles on the skin

Increased skin pigmentation

Thickened skin

Loss of hair

Salivary staining (brown color)

Head shaking