Allergic Contact Dermatitis

Allergic contact dermatitis is a highly itchy rash that occurs when a person comes into contact with a chemical if they are allergic.

Most people are unaffected by these compounds ("allergens"), but those who are sensitive to them experience immunological reactions. A small amount of the allergen can trigger an allergic reaction.

In order for a person to develop contact dermatitis, the skin must be exposed to an allergen on a regular basis. The majority of people are exposed to an allergen for years before acquiring a rash. However, once a person's skin has become sensitized to a substance, that person's skin is usually sensitive to that material for the rest of their life.

The following allergens are known to cause allergic contact dermatitis:

• Plants such as poison oak or poison ivy
• Metals, notably nickel. Nickel can be found in jewelry (earrings, watches and necklaces), buttons (jeans' inside pockets) and belt buckles.
• Aromatic scents (including those found in lotions, shampoos and other cosmetics)
• Preservatives, or substances that are used to preserve food (found in lotions or leather and other fabrics)
• Rubber
• Hair dye
• Medications

The skin may become red, swollen and blistered after being exposed to an allergen, or it may become dry and rough. Because the rash appears where the allergen comes into contact with the skin, it aids in determining the source of the allergy. A rash on the neck or wrist, for example, could indicate an allergy to the metal (nickel) in a necklace or wristwatch. Chemicals present in the leather or rubber of shoes may cause rashes on both feet. The rash may spread beyond the point of contact in extreme cases and occur elsewhere on the body.

Contact dermatitis can cause a rash as quickly as few hours after coming into contact with the allergen. Even after the allergen has been eliminated from the skin, healing can take days to weeks.

Your doctor may do a patch test if the reason for the allergic reaction is unknown. This is an allergy test for allergic contact dermatitis diagnosis. For several days, the suspected allergen can be administered to a tiny patch of sensitive skin (such as the inner arm). The area is then monitored for changes.

Treatments for Allergic Contact Dermatitis

The best treatment for allergic contact dermatitis is to avoid the allergen (the substance that causes the allergy) in the first place.

Your doctor may use or more of the following treatments for symptom relief:

• Antihistamines to relieve itching.
• Moisturizers to repair and protect damaged skin.
• Topical corticosteroids
• For severe cases, oral steroids (such as prednisone) can be given for a short time.
• Immunomodulators for the skin (Elidel®, Protopic®)

Your doctor will suggest a treatment plan that is most appropriate for you.