Abstract
ABSTRACT: Systemic contact dermatitis is a skin reaction that occurs after systemic exposure to a previously encountered allergen. Such exposure may occur via oral, intravenous, percutaneous, or inhalational routes. After exposure, dermatitis may occur at various sites. One clue to the diagnosis is the occurrence of recurrent episodes of contact dermatitis despite topical avoidance of known allergens. The treatment of systemic contact dermatitis involves avoidance of all systemic exposure to an allergen, which includes removal of the allergen from the diet. In this review, we focus on four major dietary allergens and describe relevant dietary sources to serve as a guide for patient education. These allergens are nickel, balsam of Peru, propylene glycol, and formaldehyde.