๐ ็ธฝ็ฎ้ ๏ฝ ๐ ่ฑๆๅๆ๏ผๆฌ็ฏ๏ผ ๏ฝ ๐ ๅฎๆด็ฟป่ญฏ ๏ฝ โญ ็ฒพ่ฏ็ญ่จ
CONTACT DERMATITIS
CONTACT DERMATITISย ย ICD-10: L25
Contact dermatitis is a generic term applied to acute or chronic inflammatory reactions to substances that come in contact with the skin. Irritant contact dermatitis (ICD) is caused by a chemical irritant. Allergic contact dermatitis (ACD) is caused by an antigen (allergen) that elicits a type IV (cell-mediated or delayed) hypersensitivity reaction. ICD occurs after a single exposure to the offending agent that is toxic to the skin (e.g., croton oil) and in severe cases may lead to necrosis. It is dependent on concentration of the offending agent and occurs in everyone, depending on the penetrability and thickness of the stratum corneum. There is a threshold concentration for these substances above which they cause acute dermatitis and below which they do not. This sets ICD apart from ACD, which is dependent on sensitization and thus occurs only in sensitized individuals. Depending on the degree of sensitization, minute amounts of the offending agents may elicit a reaction. Since ICD is a toxic phenomenon, it is confined to the area of exposure and is therefore always sharply marginated and never spreads. ACD is an immunologic reaction that tends to involve the surrounding skin (spreading phenomenon) and may spread beyond affected sites.