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Contact Dermatitis: Your Common Skin Rash

Contact dermatitis, also known as a skin rash, occurs for different reasons.

There are two types of contact dermatitis: allergic contact dermatitis and irritant contact dermatitis.

Allergic Contact Dermatitis

Allergic contact dermatitis occurs when an allergen comes in contact with previously sensitized skin, resulting in a rash. Previous exposure to the substance is necessary for this type of contact dermatitis to occur, but the reaction can occur any time after the first exposure. This means a substance can become an allergen at any time, even if a patient has been in contact with that substance for many years. For example, a patient may suddenly develop allergic contact dermatitis on her earlobes after wearing earrings every day for the past five years. Common allergens include cosmetics, personal hygiene products, soaps, perfumes, fabrics, and metals.

Irritant Contact Dermatitis

Irritant contact dermatitis is an inflammatory reaction to a substance that results in a skin rash. No previous exposure to the substance is necessary, so the reaction can occur with just one exposure to an irritating substance and continue with subsequent exposures. For example, a patient may develop irritant contact dermatitis after spilling pesticide on his skin. Common irritants include soaps, cleansers, fabrics, and occupational chemicals.

A biopsy performed in a dermatology office can confirm the presence of an ongoing dermatitis, but it can’t identify the causative agent or agents, which is key to preventing future reactions. To identify these agents, a comprehensive patch test is often necessary; this test should also be performed in a dermatology office.

The Department of Dermatology in Hinsdale and Lombard offers a Patch Test Clinic. Our team of trained professionals will perform a comprehensive contact allergy test on cosmetic and personal care products, clothing, occupational materials, and other substances with which a patient may come in contact at both home and work. 


Topics and Subtopics: Skin Health

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