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Wednesday, October 8, 2008

Contact dermatitis (poison ivy, oak, sumac)

Dermatitis, close-up of allergic contact
Dermatitis, close-up of allergic contact
Dermatitis, contact
Dermatitis, contact
Dermatitis, contact on the cheek
Dermatitis, contact on the cheek
Dermatitis, nickel on the sole
Dermatitis, nickel on the sole
Dermatitis, pustular contact
Dermatitis, pustular contact
Latex allergy
Latex allergy
Phytophotodermatitis on the hand
Phytophotodermatitis on the hand
Poison ivy on the knee
Poison ivy on the knee
Poison ivy on the leg
Poison ivy on the leg
Poison oak rash on the arm
Poison oak rash on the arm
Poison plants
Poison plants
Definition

Contact dermatitis is an inflammation of the skin caused by direct contact with an irritating substance.


Alternative Names

Dermatitis - contact; Allergic dermatitis; Dermatitis - allergic; Poison ivy; Poison oak; Poison sumac


Causes, incidence, and risk factors

Contact dermatitis is an inflammation of the skin caused by direct contact with an irritating or allergy-causing substance (irritant or allergen) vary in the same individual over time. A history of any type of allergies increases the risk for this condition.

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.

Common allergens associated with contact dermatitis include:

  • Poison ivy, poison oak, poison sumac
  • Other plants
  • Nickel or other metals
  • Medications
    • Antibiotics, especially those applied to the surface of the skin (topical)
    • Topical anesthetics
    • Other medications
  • Rubber
  • Cosmetics
  • Fabrics and clothing
  • Detergents
  • Solvents
  • Adhesives
  • 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, 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 cause contact dermatitis.



Review Date: 05/03/2006
Reviewed By: Michael S. Lehrer, M.D., Department of Dermatology, University of Pennsylvania Medical Center, Philadelphia, PA. Review provided by VeriMed Healthcare Network.

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