Contact dermatitis is a type of skin rash. It occurs when skin comes into contact with chemicals or physical substances that cause an allergic or irritant reaction. Contact dermatitis can occur from exposure to many different compounds found both in the home and at work. There are two types of contact dermatitis:
- Allergic contact dermatitis: This occurs when skin, which has become sensitive to a certain substance (allergen), comes in contact with that substance again. This is a delayed skin reaction that typically develops 12 to 72 hours after exposure.
- Irritant contact dermatitis: This occurs when the skin is repeatedly exposed to a mild irritant (such as detergent or solvents) over a long period of time. If skin is exposed to a strong irritant (such as acid, alkali, solvent, strong soap, or detergent), skin damage can be immediate.
What are the common sources of allergic contact dermatitis?
Not everyone reacts to allergens. However, some people become allergic to something that they had previously tolerated for many years. Skin can become allergic to a substance after many exposures or after just one exposure. Common sources of allergic contact dermatitis include:
- Metals such as nickel (present in costume jewelry or snaps on jeans). Nickel may cause allergic dermatitis in areas in contact with the metal (for example, the ears under earrings). Gold is also becoming a widespread allergen.
- Fragrances, such as those found in perfumes, soaps, lotions, and shampoos
- Topical medications, such as antibiotics (Neosporin®) or anti-itch preparations. These may cause an allergic reaction or even worsening of the initial problem and are often misdiagnosed as an infection.
- Preservatives. These substances keep topical products from spoiling.
- Sunscreens. These commonly cause a hive-like rash that can appear hours or days after sun exposure.
- Rubber ingredients. Rubber is a common source of work-related allergies. It can cause immediate allergic reactions, such as itching, burning, or welts. Some people experience itching and tearing eyes or even shortness of breath.
What are the common sources of irritant contact dermatitis?
Detergents, soaps, cleaners, waxes, and chemicals are substances that can irritate the skin. They can wear down the oily, protective layer on the skin surface and lead to irritant contact dermatitis. Irritant contact dermatitis is common among people who regularly work with strong chemicals or detergents, such as restaurant, maintenance, and chemical workers. It is also seen in people who do a lot of housework due to contact with cleaning products.
Are certain occupations at greater risk?
Some occupations have more exposure to chemicals or substances that can result in sensitization and cause allergic contact dermatitis. Examples of these include dental workers, health care workers, florists, hairdressers, and machinists.
What are the symptoms of contact dermatitis?
Contact dermatitis symptoms can range from mild redness and dryness to severe pain and peeling that can be disabling.
Allergic contact dermatitis symptoms include:
- Reddening of skin (either in patches or all over the body)
- Intermittent dry, scaly patches of skin
- Blisters that ooze
- Burning or itching that is usually intense without visible skin sores (lesions)
- Swelling in the eyes, face, and genital areas (severe cases)
- Sun sensitivity
- Darkened, “leathery," and cracked skin
Allergic contact dermatitis can be very difficult to distinguish from other rashes.
Irritant contact dermatitis symptoms include:
- Mild swelling of skin
- Stiff, tight feeling skin
- Dry, cracking skin
- Painful ulcers on the skin
Symptoms vary depending on the cause of dermatitis.
How can I know if I have contact dermatitis?
If you have a skin rash that won’t go away, visit your health care provider. If he or she suspects allergic contact dermatitis, patch testing may be performed. In this test, small samples of chemicals are placed on an area of skin on your back to see if a rash develops. There are no needles or pricking of the skin. These areas of the skin are then evaluated after 48 hours and again at 96 hours or one week.
The advantage of patch testing is that, if you are allergic to any chemical/product, the allergens can be identified, and your healthcare provider can effectively treat the rash with therapy and avoidance of the allergen(s). There are no tests that can be done for irritant contact dermatitis. Tell your healthcare provider about any irritating substances or chemicals that you regularly come into contact with (including cosmetics, lotions, and nail polish).
With either type of contact dermatitis, you can avoid substances you suspect and see if the rash improves.
How is contact dermatitis treated?
The type of treatment depends on the cause of contact dermatitis. Common treatments include oral and/or topical corticosteroids, antihistamines, lotions and creams, or oatmeal baths.
How can I prevent contact dermatitis?
For allergic contact dermatitis:
- Avoid contact with substances that cause the skin rash
- Wash any area that comes into contact with allergic substances
- Learn to recognize poison oak and poison ivy
For irritant contact dermatitis:
- Wear cotton gloves under rubber gloves for all wet work. Use plain petroleum jelly to protect the skin. Reapply the petroleum jelly two or three times a day and after washing your hands.
- Avoid contact with substances that irritate the skin
- Use mild soaps
- Use hand creams and lotions frequently