Allergic contact dermatitis is a skin condition that can occur in people who are sensitive to certain allergens. Allergens are substances that only cause skin irritation in some individuals, but are not universally harsh or abrasive. When a person who is sensitive to a particular allergen comes into direct contact with it, he or she may begin to experience skin irritation.
The symptoms of allergic contact dermatitis may not become apparent until about one to two days after a person’s skin has touched an allergen, but in some instances the symptoms may start to show within hours. Red patches may appear on the area of the skin that was exposed to the allergen, typically causing it to itch profusely. In more severe cases, blisters may form on the skin.
One of the most common natural allergens responsible for allergic contact dermatitis are members of the poisonous plant family, such as poison oak, ivy, and sumac. If a person is sensitive to these plants, he or she may experience a serious of tiny blisters where the plant touched the skin. Allergic reactions from poisonous plants tend to occur most often on areas where the plant could accidentally touch the skin, such as the legs and arms.
Beauty products, such as moisturizers, soaps, and cosmetics, are also likely causes of skin reactions. These items often contain perfumes to both cover the strong smells of its chemical ingredients and to add specific scents to the products. People who are allergic to fragrances may experience skin tightness, itchiness, or a light rash where the product was applied. The chemical preservatives that are used in beauty products to prevent spoilage may also cause skin reactions. Permanent hair dyes contain paraphenylene-diamine (PPD), a chemical that may cause allergic contact dermatitis of the scalp and hairline.
Items made from nickel are also common culprits of allergic contact dermatitis. Some people may experience symptoms after wearing nickel jewelry, especially earrings, or wearing clothing or accessories containing nickel, such as zippers, snaps, or belt buckles. A person is more susceptible to nickel reactions during hot weather because sweat makes the nickel even more irritating to the skin.
The rashes and blisters that occur after exposure to an allergen are typically not serious and will often go away on their own without treatment. A doctor may prescribe a steroid ointment that may help soothe itchy skin. Future cases may be prevented by simply avoiding the allergen, but this may be difficult if the person is not sure what items or products are causing the problems. To determine the root of the outbreaks, a doctor may perform patch tests, in which he or she applies possible items or products onto a small area of the patient’s skin to see which one causes the condition.