Contact dermatitis is a reaction that happens after your skin comes in direct contact with certain substances. The substances may be:

• Irritants. These cause direct skin irritation and inflammation. They are the most common cause of contact dermatitis.
• Allergens. These cause the body's immune system to have an allergic reaction. The body releases defense chemicals that cause skin symptoms. The reaction may not start until 24 to 48 hours after exposure. Allergens are a less common cause of contact dermatitis.

Contact dermatitis most often affects adults. But it can affect people of all ages.

Common irritants that can cause contact dermatitis include:

• Soaps.
• Drool.
• Foods.
• Detergents.
• Harsh baby lotions.
• Perfumes.
• Rubber (latex).
• Antibiotics.
• Fragrances.
• Preservatives.

Common allergens that can cause a contact dermatitis reaction include:

• Poison ivy. Poison ivy is part of a plant family that includes poison oak and sumac. It's one of the most common causes of a contact dermatitis reaction.
• Metals. Many chemical agents can cause allergic contact dermatitis. Nickel, chrome, and mercury are the most common metals that cause it.
  • 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. These will likely cause skin reactions in people sensitive to nickel.
  • Mercury, which is found in contact lens solutions. This can cause a reaction in some people.
• Cosmetics. Many types of cosmetics can cause allergic contact dermatitis. Permanent hair dyes that contain paraphenylenediamine often cause it. Other products that may cause problems include perfumes, eye shadow, nail polish, lipstick, and some sunscreens.
• Medicines. Neomycin is found in antibiotic creams, such as triple antibiotic ointment. It's a common cause of medicine-related contact dermatitis. Penicillin, sulfa medicines, and local anesthetics, such as procaine hydrochloride, are other possible causes.

Each person's symptoms may be different. Some of the most common symptoms include:

• Mild redness and swelling of the skin.
• Blistering.
• Itching or burning.
• Scaly, thickened skin.

Many of these symptoms may be caused by other skin conditions. Always talk with your doctor for a diagnosis.

Diagnosis is often based on a health history and physical exam. Patch testing can be done to find the substance that's causing the rash. A skin biopsy may also be done.

Treatment will depend on your symptoms, age, and general health. It will also depend on how severe the condition is.

The best treatment is to find and stay away from the things that may have caused the reaction. Here is some common treatment advice for mild to moderate reactions:

• Thoroughly wash the skin with soap and water as soon after the exposure as possible.
• Wash clothing and all objects that touched plant resins (such as poison ivy) 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.
• Use medicines advised by your doctor to ease itching. You may need to put the medicine on your skin or take the medicine by mouth (orally).
  • Steroid creams or newer immunomodulator creams are used on the skin to ease itching.
  • Oral or injected steroids and oral antihistamines are used to control the itching and rash.
• Don't scratch the rash. Scratching may cause scarring or a bacterial infection.
• For severe reactions, always contact your doctor.

If the reaction is bad and the substance that caused it can't be found, a series of patch tests may be done to help figure out the allergen.

The only way to prevent contact dermatitis is to prevent contact with the irritant or allergen that causes it.

• Contact dermatitis is a reaction that happens after skin comes in contact with certain substances.
• Skin irritants cause most contact dermatitis reactions.
• Allergens, such as poison ivy, can also cause this condition.
• It's important to find the cause so you can stay away from that substance.
• Topical and oral medicines may be advised by your doctor to ease itching.

Tips to help you get the most from a visit to your doctor:

• Know the reason for your visit and what you want to happen.
• Before your visit, write down questions you want answered.
• Bring someone with you to help you ask questions and remember what your doctor tells you.
• At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your doctor gives you.
• Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
• Ask if your condition can be treated in other ways.
• Know why a test or procedure is recommended and what the results could mean.
• Know what to expect if you do not take the medicine or have the test or procedure.
• If you have a follow-up appointment, write down the date, time, and purpose for that visit.
• Know how you can contact your doctor if you have questions, especially after office hours or on weekends.