Allergic contact dermatitis comes in the form of itching, redness, and blisters and is caused by allergens coming in contact with skin. The condition is typically diagnosed by studying the distribution of the rash and determining the materials your skin comes into contact with throughout the day. In more elusive cases, a patch test will be performed using small amounts of potential allergens on strips of tape that will subsequently reveal a small red spot indicating the offending allergen.
Common allergens include: nickel, rubber, chromates, hair dyes, skin care products, and poisonous plants. Treatment can range from topical antihistamines to oral and injectable antibiotics or other anti-inflammatory/immunologic agents.