What is contact dermatitis?
Contact dermatitis is a reaction that happens after your skin comes in contact with certain substances.
Skin irritants cause most contact dermatitis reactions. Other cases are caused by allergens, which trigger an allergic response. The reaction may not start until 24 to 48 hours after exposure. Contact dermatitis, caused by an irritant that is not an allergic response, happens from direct contact with the irritant.
Allergic contact dermatitis most commonly affects adults, but it can affect people of all ages.
What causes contact dermatitis?
Some of the most common causes of contact dermatitis include:
- Different foods
- Harsh baby lotions
- Rubber (latex)
Plants, metals, cosmetics, and medicines may also cause a contact dermatitis reaction:
Poison ivy is part of a plant family that includes poison oak and sumac. It is one of the most common causes of a contact dermatitis reaction.
Many chemical agents can cause allergic contact dermatitis. Nickel, chrome, and mercury are the most common metals that cause contact dermatitis:
- Nickel is found in costume jewelry, and belt buckles. Watches, zippers, snaps, and hooks on clothing may also contain nickel.
- Chrome-plated items, which contain nickel, will probably cause skin reactions in people sensitive to nickel.
- Mercury, which is found in contact lens solutions, can cause a reaction in some people.
Many types of cosmetics can cause allergic contact dermatitis. Permanent hair dyes that contain paraphenylenediamine are frequent causes. Other products that may cause problems include dyes used in clothing, perfumes, eye shadow, nail polish, lipstick, and some sunscreens.
Neomycin, which is found in antibiotic creams, such as triple antibiotic ointment, is a common cause of medicine-related contact dermatitis. Penicillin, sulfa medicines, and local anesthetics, such as Novocaine or paraben, are other possible causes.
How is contact dermatitis treated?
Specific treatment for contact dermatitis will be determined by your healthcare provider based on:
- Your age, overall health, and medical history
- Extent of the reaction
- Your tolerance for specific medicines, procedures, or therapies
- Expectations for the course of the reaction
- Your opinion or preference
The best treatment is to identify and avoid the substances that may have caused the allergic reaction. The following are common treatment recommendations for mild to moderate reactions:
- Thoroughly wash skin with soap and water as soon after the exposure as possible.
- Wash clothing and all objects that touched plant resins (poison ivy/oak) to prevent re-exposure.
- Use wet, cold compresses to soothe inflammation if blisters are broken.
- Use barrier creams to block certain substances if there is a chance of re-exposure in the future.
- Medicines you put on your skin or ones you take by mouth may be recommended by your healthcare provider to relieve itching.
- Cortisone creams are used topically to relieve itching.
- Oral or injected steroids and oral antihistamines are used to control the itching and rash.
- Avoid scratching the rash to prevent a bacterial infection.
- For severe reactions, always contact your healthcare provider.
If the reaction is significant and the substance that caused it can't be determined, your healthcare provider may do a series of patch tests to help identify the irritant.