Atopic dermatitis is a pruritic (itchy) skin disease in dogs and cats. With this condition, an allergic reaction occurs when an animal inhales airborne substances (pollen, house dust) or ingests a substance to which they are sensitive. Another form of allergic reaction in pets caused by contact with substances is known as contact dermatitis. Contact dermatitis appears where direct exposure to the skin occurs, while atopic dermatitis will appear on both sides of the body.

The allergic reaction causes the animal to rub, lick, bite or scratch. Unlike humans, animals with atopic dermatitis only occasionally cough, sneeze or get asthma. Instead, atopic dermatitis in pets presents as persistent itchy skin.

The itching may be localized to certain areas or it may be over the entire body. Usually, the feet, face, ears, armpits and front legs are affected. This is in contrast to a flea allergy where the rump, tail, groin and thighs are usually affected. About half of the animals with atopic dermatitis will also be allergic to fleas and will have symptoms of both diseases.

The usual progression of a skin disease involves an underlying trigger (disease syndrome) that causes primary lesions such as papules, pustules, and vesicles. Pruritus is a common clinical sign in many diseases, and, in conditions that are not inherently pruritic, it is often present because of secondary infections or as a result of production of inflammatory mediators. As the inflammatory changes progress, crusting and scaling develop. If the process involves the deeper dermis, exudation, pain, and sloughing of the skin may occur.

Secondary bacterial and yeast infections commonly develop as a result of skin inflammation. As dermatitis becomes chronic, acute signs of inflammation (e.g., erythema) subside and primary lesions become obscured by signs of chronic inflammation (thickening of the skin, hyperpigmentation, scaling, seborrhoea). Often, the skin becomes drier; if pruritus is not a component of the underlying trigger, it will often develop at this stage. Resolution of dermatitis requires identification of the underlying cause and treatment of secondary infections or other complications.

Atopic dermatitis due to food reactions can be cured, while those due to airborne substances cannot, but can be controlled with medication in most cases. Usually, cortisone-type drugs (steroids) are used for the treatment of atopic dermatitis. They are very effective anti-inflammatory, anti-itch medications. However, steroids have more side effects (excessive drinking, urinating and eating along with increased susceptibility to infection) than other treatments.

If used long-term without supervision, steroids may also decrease your pet’s longevity. Unfortunately, steroids may be the only treatment that will control your pet’s symptoms. If you do not want your pet on long-term steroids, or if they cannot tolerate them, there are alternatives.

There are a number of new treatments available for dermatitis, some with less side affects than others, but as with most long term medication- regular check ups which may involve blood tests are of utmost importance.