Allergic Contact Dermatitis

Condition Overview

Irritant contact dermatitis is caused by the direct effect of a chemical or irritant on the skin. It occurs in areas where the skin is not well protected by hair such as the feet, chin, nose, hocks, stifles, and the under-surface of the body including the scrotum.

Symptoms

Irritant contact dermatitis produces itchy red bumps and inflammation of the skin. You may notice moist, weepy spots, blisters, and crusts. The skin becomes rough and scaly and hair is lost. Excessive scratching damages the skin and sets the stage for secondary pyoderma.

Less commonly, the skin becomes sensitized to a certain chemical and a delayed type of hypersensitivity reaction develops. This is allergic contact dermatitis. This rash is indistinguishable from that of irritant contact dermatitis, but appears after repeated exposure and often spreads beyond the site of contact.

Flea contact dermatitis is an allergic contact dermatitis. The signs include itching, redness, hair loss, and the development of excoriations (abrasive skin wounds), scabs, and crusts beneath the collar.

All symptoms +

Causes

Chemicals that can cause irritant dermatitis include acids and alkalis, detergents, solvents, soaps, and petroleum by products.

Allergic contact dermatitis can be caused by chemicals found in soaps, flea collars, shampoos, wool and synthetic fibers, leather, plastic and rubber dishes, grasses and pollens, insecticides, petrolatum, paint, carpet dyes, and rubber and wood preservatives. Chemicals used to clean your carpet are a frequent source of irritation. Neomycin, found in many topical medications, can produce allergic contact dermatitis, as can other drugs and medications.

Diagnosis

Skin will be visible irritated and itchy. See Symptoms above for specific descriptions of each type of allergic reaction.

Treatment

Consider the area of involvement and identify the chemical or skin allergen causing the problem and prevent further exposure.

Treat infected skin with a topical antibiotic ointment such as triple antibiotic. Topical and oral corticosteroids prescribed by your vet can relieve itching and inflammation.

Prevention

If your pet is suffering flea collar dermatitis, remove the flea collar and change to a topical flea preventative from Frontline, Advantage, or Advantix.

Support

Please contact your veterinarian for assistance if you think your pet may have this condition.