Contact dermatitis.

Allergic contact dermatitis and irritant contact dermatitis in the small animal may result in clinical lesions with similar anatomical locations. Allergic contact dermatitis is generally noted in ventral and lightly haired regions as a papular, erythematous, and sometimes vesicular dermatitis. It is intensely pruritic and is the result of many months (and usually years) of exposure to the contact allergen. Total avoidance of the allergenic substance is the only successful long-term management. Irritant contact dermatitis occurs when an irritating substance is applied to the skin. It is a sequela that would occur in the majority of a population having contact with the compound. It is generally more painful than pruritic. Removal of the irritant will permit resolution of the signs.