Medically reviewed on Aug 27, 2013 by L. Anderson, PharmD.
Contact dermatitis is an inflammation of the skin caused by direct contact with an irritating substance. It is also known as allergic dermatitis.
A well known contact dermatitis is that which occurs upon exposure to Poison Ivy.
What causes contact dermatitis and who is at risk?
Contact dermatitis is an inflammation of the skin caused by direct contact with an irritating or allergy-causing substance (irritant or allergen). These can vary in the same individual over time. A history of any type of allergies increases the risk for this condition.
Common allergens associated with contact dermatitis include:
- Poison ivy, poison oak, poison sumac
- Other plants
- Nickel or other metals
- Antibiotics, especially those applied to the surface of the skin (topical)
- Topical anesthetics
- Other medications
- Fabrics and clothing
- Fragrances, perfumes
- Other chemicals and substances
Contact dermatitis may involve a reaction to a substance that the person is exposed to or uses repeatedly. Although there may be no initial reaction, repeated use (for example, of nail polish remover, preservatives in contact lens solutions, or repeated contact with metals in earring posts and the metal backs of watches) can cause eventual sensitization and reaction to the product.
Some products cause a reaction only when they contact the skin and are exposed to sunlight (photosensitivity). These include shaving lotions, sunscreens, sulfa ointments, some perfumes, coal tar products, and oil from the skin of a lime. A few airborne allergens, such as ragweed or insecticide spray, can also cause contact dermatitis.
Types of Contact dermatitis
Irritant dermatitis, the most common type of contact dermatitis, involves inflammation resulting from contact with acids, alkaline materials such as soaps and detergents, solvents, or other chemicals. The reaction usually resembles a burn.
The second most common type of contact dermatitis is caused by exposure to a material to which the person has become hypersensitive or allergic. The skin inflammation varies from mild irritation and redness to open sores, depending on the type of irritant, the body part affected, and the sensitivity of the individual.
Overtreatment dermatitis is a form of contact dermatitis that occurs when treatment for another skin disorder causes irritation.
- Itching (pruritus) of the skin in exposed areas
- Skin redness or inflammation in the exposed area
- Tenderness of the skin in the exposed area
- Localized swelling of the skin
- Warmth of the exposed area (may occur)
- Skin lesion or rash at the site of exposure
- Lesions of any type: redness, rash, papules (pimple-like), vesicles, and bullae (blisters)
- May involve oozing, draining, or crusting
- May become scaly, raw, or thickened
The diagnosis is primarily based on the skin appearance and a history of exposure to an irritant or an allergen.
According to the American Academy of Allergy, Asthma, and Immunology, "Patch testing is the gold standard for contact allergen identification." Allergy testing with skin patches may isolate the suspected allergen that is causing the reaction.
Patch testing is used for patients who have chronic, recurring contact dermatitis. It requires three office visits and must be done by a clinician with detailed experience in the procedures and interpretation of results. Patients should bring suspected materials with them, especially if they have already tested those materials on a small area of their skin and noticed a reaction.
Contact your doctor if:
Call your health care provider if your symptoms seem to be caused by contact dermatitis and they are severe or if you do not notice any improvement after treatment.
Initial treatment includes thorough washing with lots of water to remove any trace of the irritant that may remain on the skin. Further exposure to known irritants or allergens should be avoided.
In some cases, the best treatment is to do nothing to the area.
Topical corticosteroid medications may reduce inflammation. Carefully adhere to instructions when using topical steroids because overuse of these medications, even low-strength over-the-counter topical steroids, may cause a troublesome skin condition. In severe cases, systemic corticosteroids may be needed to reduce inflammation. These are usually tapered gradually over about 12 days to prevent recurrence of the rash.
Wet dressings and soothing, antipruritic (anti-itch), or drying lotions may be recommended to reduce other symptoms.