Determining the cause of contact dermatitis .

Once the diagnosis of contact dermatitis is suspected, it is important to challenge your skin in a process referred to as patch testing. Patch testing is performed in the office setting. Dr. Harvey and Dr. Hardy will apply various strengths of topical compounds to the skin. He will then assess the tested areas in 48 hours to see if a localized skin rash develops. Once an allergen or irritant has been identified, Dr. Harvey and Dr. Hardy will review with you the sources of these agents. In this way you may practice avoidance techniques to help to minimize your risk of developing new skin reactions.
Determining the cause of contact dermatitis is not always easy. The person's occupation, hobbies, household duties, vacations, clothing, topical drug use, cosmetics, and household members' activities must be considered. Most people are unaware of all the substances that touch their skin. Often, the location of the initial rash is an important clue, particularly if it occurs under an item of clothing or jewelry or only in areas exposed to sunlight. However, many substances that people touch with their hands are unknowingly transferred to the face, where the more sensitive facial skin may react even if the hands do not.
Contact dermatitis occurs in two forms. The irritant form is more common and results from an exposure to a substance that is toxic to the skin and initiates the inflammatory reaction. This could be a chemical or even a cream, cosmetic or lotion. The other form is allergic in origin. This may refer to the poison ivy, oak or sumac. Beside these common plants, in teens, allergic contact dermatitis may be due to nickel jewelry, preservatives and topical antibiotics.