Contact dermatitis is a red, itchy rash caused by direct contact with a substance or an allergic reaction to it. The rash isn't contagious or life-threatening, but it can be very uncomfortable.
Many substances can cause such reactions, including soaps, cosmetics, fragrances, jewelry and plants.
To treat contact dermatitis successfully, you need to identify and avoid the cause of your reaction. If you can avoid the offending substance, the rash usually clears up in two to four weeks. You can try soothing your skin with cool, wet compresses, anti-itch creams and other self-care steps.
Contact dermatitis can appear as an itchy, red rash. In this photo, the irritation is likely due to a watchband or to soap residue trapped beneath the band.
Contact dermatitis usually occurs on areas of your body that have been directly exposed to the reaction-causing substance — for example, along a calf that brushed against poison ivy or under a watchband. The rash usually develops within minutes to hours of exposure and can last two to four weeks.
Signs and symptoms of contact dermatitis include:
See your doctor if:
Seek immediate medical care in the following situations:
Contact dermatitis usually affects areas of skin directly exposed to an offending substance. Here, the dry, red rash is likely caused by cosmetics or soap.
Blisters such as these are common in a skin reaction to urushiol, the highly allergenic oily substance in poison ivy.
Contact dermatitis is caused by a substance you're exposed to that irritates your skin or triggers an allergic reaction. The substance could be one of thousands of known allergens and irritants. Some of these substances may cause both irritant contact dermatitis and allergic contact dermatitis.
Irritant contact dermatitis is the most common type. This nonallergic skin reaction occurs when a substance damages your skin's outer protective layer.
Some people react to strong irritants after a single exposure. Others may develop signs and symptoms after repeated exposures to even mild irritants. And some people develop a tolerance to the substance over time.
Common irritants include:
Allergic contact dermatitis occurs when a substance to which you're sensitive (allergen) triggers an immune reaction in your skin. It usually affects only the area that came into contact with the allergen. But it may be triggered by something that enters your body through foods, flavorings, medicine, or medical or dental procedures (systemic contact dermatitis).
You may become sensitized to a strong allergen such as poison ivy after a single exposure. Weaker allergens may require multiple exposures over several years to trigger an allergy. Once you develop an allergy to a substance, even a small amount of it can cause a reaction.
Common allergens include:
Children develop the condition from the usual offenders and also from exposure to diapers, baby wipes, sunscreens, clothing with snaps or dyes, and so on.
Some jobs and hobbies put you at higher risk of contact dermatitis. Examples include:
Contact dermatitis can lead to an infection if you repeatedly scratch the affected area, causing it to become wet and oozing. This creates a good place for bacteria or fungi to grow and may cause an infection.
General prevention steps include the following:
Your doctor may be able to diagnose contact dermatitis and identify its cause by talking to you about your signs and symptoms, questioning you to uncover clues about the trigger substance, and examining your skin to note the pattern and intensity of your rash.
Your doctor may recommend a patch test to see if you're allergic to something. This test can be useful if the cause of your rash isn't apparent or if your rash recurs often.
During a patch test, small amounts of potential allergens are applied to adhesive patches, which are then placed on your skin. The patches remain on your skin for two to three days, during which time you'll need to keep your back dry.
Your doctor then checks for skin reactions under the patches and determines whether further testing is needed.
Patch testing can be helpful in determining if you're allergic to a specific substance. Small amounts of different substances are placed on your skin under an adhesive coating. Your doctor then checks for a skin reaction under the patches.
If home care steps don't ease your signs and symptoms, your doctor may prescribe medications. Examples include:
To help reduce itching and soothe inflamed skin, try these self-care approaches:
Avoid the irritant or allergen. The key to this is identifying what's causing your rash and staying away from it. Your doctor may give you a list of products that typically contain the substance that affects you. Also ask for a list of products that are free of the substance that affects you.
If you're allergic to the metal in a piece of jewelry, you may be able to wear it by putting a barrier between you and the metal. For example, line the inside of a bracelet with a piece of clear tape or paint it with clear nail polish.
You're likely to start by seeing your primary care doctor. He or she might refer you to a doctor who specializes in skin disorders (dermatologist).
Because appointments can be brief, it's a good idea to be well-prepared for your appointment.
For contact dermatitis, some basic questions you could ask your doctor include:
Your doctor is likely to ask you questions such as the following: