Contact dermatitis accounts for 70-90% of all occupational skin diseases. 1 It is an inflammatory skin condition induced by exposure to an external irritant or allergen (table 1⇓). A prevalence of 8.2% was seen in a recent cross sectional study of 12 377 subjects across five European countries, in which a randomly selected group of 3119 patients were patch tested. 2 The condition can have a detrimental impact on personal and social relationships, quality of life, and even threaten employment. [3][4][5] What are the different types of contact dermatitis?Irritant contact dermatitis is a non-immunologic response that occurs as a consequence of direct damage to the skin, by chemicals or physical agents, faster than the skin is able to repair itself. 6 7 Approximately 80% of cases of contact dermatitis are irritant contact dermatitis. 8 Common irritants include soaps, detergents, water, solvents, cutting oils, and food ingredients. 8 The hands, particularly finger web spaces (fig 1⇓), and the face are commonly affected. 6 Allergic contact dermatitis comprises 20% of cases of contact dermatitis. It is a type IV delayed hypersensitivity reaction to an external allergen, which occurs only in an individual who has previously been sensitised. 6 Re-exposure to the allergen results in circulating memory T cells homing in to the skin and eliciting an immunologic reaction that causes skin inflammation, typically within 48 hours. [9][10][11][12][13] For personal use only: See rights and reprints