Allergic Contact Dermatitis
Allergic contact dermatitis is a condition that results from the skin's reaction to a substance (allergen) to which it has become sensitized, or allergic. Some of the substances that can lead to this type of eczema include poison ivy, laundry detergent, and perfume. While symptoms vary, it's not unusual for people with this condition to have blisters or itchy skin. Treatment options can include avoiding the allergenic substance, taking medication, or using lubricants.
What Is Allergic Contact Dermatitis?Allergic contact dermatitis is a type of eczema caused by exposure to substances in the environment. It is one of the two types of contact dermatitis (irritant contact dermatitis is the other).
Allergic contact dermatitis results from the skin's reaction to a substance (allergen) to which it has become sensitized, or allergic. Normally, the skin doesn't react the first time it meets up with an allergen. Sometimes it occurs with the second exposure. But in other cases, it takes years and many exposures for hypersensitivity to a particular substance to develop. Once sensitized, the skin will usually become inflamed within hours or days after allergic contact.
What Causes It?Virtually anything can cause allergic contact dermatitis in a susceptible person. Some examples of substances that can cause it include:
- Poison ivy
- Poison oak
- Poison sumac
- Cosmetics, such as hair sprays, shampoos, makeup, sunscreens, perfumes, shaving cream, nail polish, lipstick, deodorants, and acne medications
- Dyes or fabric finishes
- Laundry detergent
- Fragrances, such as perfume or aftershave lotion
- Certain metals, like nickel
- Chemicals in the air, such as sprays, perfumes, chemical dusts, or plant pollen (ragweed)
- Cashew nuts (which contain a chemical similar to poison ivy)
- Formaldehyde (found in certain shampoos and cosmetics)
- Certain medicines placed on the skin, such as certain antibiotics
- Rubber, such as the rubber contained in latex surgical gloves, adhesives, shoes (which can cause shoe dermatitis), or the elastic in bras and underwear.
Some chemicals may cause allergic contact dermatitis only after they have been exposed to sun. This process is called photosensitization. When dermatitis occurs on the left side of a man's face and neck -- the side exposed to the sun while driving a car -- photosensitization caused by aftershave lotion fragrances should be suspected.