Allergic reactions to environmental chemicals can result in such commonly known conditions as poison ivy or oak. Exposure to chemicals that cause your skin's allergy system to produce inflammation known as contact dermatitis leads to weeks of blisters and itching. Finding the culprit can often be achieved through taking a careful history of recent chemical exposures, including detergents, fabric softeners, dyes and soaps/cosmetics. Occassionally testing the skin to commonly known allergens (patch testing) is needed to help in finding the cause. Treatment with anti-allergy topical and oral medications helps alleviate and limit your suffering.
These are examples of Contact Dermatitis from Poison Ivy:
