DefinitionUrticaria (ICD 10: L50.8 -possibly F54) is divided into several subtypes (e.g. acute, chronic, physical, and autoimmune urticaria) and represents one of the most frequent skin diseases. The traditional definition of chronic urticaria is the occurrence of daily or almost daily hives for more than 6 weeks, in contrast to acute urticaria which disappears within less than 6 weeks. Physical urticarias, such as pressure and cold urticaria, or urticaria factitia also frequently occur concurrently with chronic urticaria. In addition, urticaria is associated in about 40% with angioedema. In general, hives persist less than 24 h, whereas in urticaria vasculitis, which in former times was included in urticaria subtypes due to historical reasons, hives persist more than 24 h. The trigger factors for urticaria are manifold. In more than 80% of cases urticaria is triggered by an inflammatory focus, a subclinical infection, or autoimmune actions. Additionally, non-specific pharmacological or toxin-mediated release of inflammatory mediators of basophils and mast cells can trigger urticaria. Psychodermatologically, chronic urticaria is seen as a multifactorial dermatologic disorder which can be substantially influenced by psychological factors [Schneider and Gieler, 2001]. Various studies report an association between stress, anxiety, or depressive symptoms and chronic urticaria [Sheehan-Dare et al., 1990;Brahler et al., 1994], however, not assuming a causality as reviewed recently [Buffet, 2003]. In daily practice, however, stress is an important trigger factor for urticaria. Urticaria symptoms affect everyday life, limiting and impairing physical and emotional functioning, and act as an indirect burden on life satisfaction underlining the major impact on quality of life [Baiardini et al., 2003]. With regard to the subtype of urticaria the impact on quality of life is different, as physical urticaria such as delayed pressure urticaria was shown to have a higher impact with decreased quality of life than other types [O'Donnell et al., 1997].
Dermatological DiagnosticsThe clinical assessment of urticaria includes taking the patient's history as well as physical examination. Urticaria is divided into the acute (symptoms less than 6 weeks) and the chronic type (symptoms more than 6 weeks), which is identifiable by exact acquisition of data on urticaria symptoms. For the detection of specific trigger factors, such as pressure, cold contact, or autoimmune interactions, specific tests, e.g. pressure test, cold arm bath, cold-cylinder test, and/or autologous serum skin test, are recommended . As more than 80% of chronic urticarias are triggered by chronic infections or subclinical foci specific laboratory tests are helpful: e.g. CRP (c-reactive protein), differential hemogram, serology for streptococcus, staphylococcus, and yersinia, careful testing for helicobacter pylori infection, and autologous serum skin test . In acute urticaria however, no specific dermatological investigations are recommended, as acute urticaria gener...