Allergic contact dermatitis is caused by a chemical reaction of a hapten (allergen) and your skin. Many different substances, or allergens, can cause allergic contact dermatitis, including nickel, rubber (latex), dyes, poison ivy, and poison oak. Allergens typically cause no trouble for most people. But once the skin becomes sensitive or allergic to the substance, any exposure will produce a rash. The rash usually doesn’t start until a day or two later, but can start as soon as hours or as late as a week.
Allergic contact dermatitis usually shows redness, swelling and water blisters ranging from tiny to large. The blisters may break, forming crusts and scales. Untreated, the skin may darken and become leathery and cracked. Allergic contact dermatitis can be difficult to distinguish from other rashes, especially after it has been present for a while.
To treat allergic contact dermatitis, you and your dermatologist will discuss the materials that have touched your skin at work and home to try to identify the allergen. Your dermatologist may also perform patch tests. Patch testing is a safe and relatively quick way to diagnose contact allergies. A small amount of the suspected allergen is applied to the skin for a fixed time, usually two days. At Sand Dermatology, the North American 80 panel is used to determine the causative agent.