page_title: Contact dermatitis
section_title: Allergic contact dermatitis
hierarchical_section_title: Contact dermatitis / Causes / Allergic contact dermatitis
caption_attribution_description: English: One day after contact with Poison ivy in a 3 yr old girl فارسی: تاول حاصل از تماس با پیچک سمی ، یک روز پس از تماس در یک دختربچه سه ساله
context_page_description: Contact dermatitis is a type of inflammation of the skin.
  It results from either exposure to allergens or irritants. Phototoxic dermatitis occurs when the allergen or irritant is activated by sunlight. Diagnosis of allergic contact dermatitis can often be supported by patch testing.
context_section_description: Allergic contact dermatitis (ACD) is accepted to be the most prevalent form of immunotoxicity found in humans, and is a common occupational and environmental health problem. By its allergic nature, this form of contact dermatitis is a hypersensitive reaction that is atypical within the population. The mechanisms by which this reaction occurs are complex, with many levels of fine control. Their immunology centres on the interaction of immunoregulatory cytokines and discrete subpopulations of T lymphocytes.
  Allergens include nickel, gold, Balsam of Peru (Myroxylon pereirae), chromium, and the oily coating from plants of the genus Toxicodendron, such as poison ivy, poison oak, and poison sumac.
caption: 3-year-old girl with contact dermatitis, one day after contact with poison ivy
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