Health Encyclopedia

Contact Dermatitis

Contact Dermatitis

Contact dermatitis is inflammation of the skin caused by contact with a substance that causes an allergic reaction. A minor case of contact dermatitis may cause mild redness of the skin or a rash of small red bumps, while a more severe reaction may cause swelling, redness, and larger blisters.

A rash usually starts about 48 hours after exposure to the irritating substance. Common causes of contact dermatitis include:

  • Poisonous plants, such as poison ivy, oak, or sumac.
  • Soaps, detergents, shampoos, perfumes, cosmetics, or lotions.
  • Jewelry or fabrics.
  • New tools, toys, appliances, or other objects.
  • Latex gloves.

The location of the rash may provide a clue about the cause.

Contact dermatitis does not usually occur with the first exposure to the irritating substance (allergen). After a reaction to the substance occurs for the first time, a rash can occur in response to even very small amounts of the substance.

Last Revised: April 17, 2012

Author: Healthwise Staff

Medical Review: Adam Husney, MD - Family Medicine & Amy McMichael, MD - Dermatology

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