[Which investigations should be performed in chronic urticaria?]

Chronic urticaria is frequent. Apart from physical and allergic urticaria, a cause is infrequently identified. A lot of causes are suspected but frequently not well documented. As a consequence, very different diagnostic recommendations are proposed to the clinician. We have performed an extensive review of the literature, in order to determine the quality of evidence for each suspected etiology. The search has been performed in the following data base Embase, Pascal, Cochrane Library and Medline, on a ten years period. It has been completed with data from the selected articles. Infectious diseases, thyroid diseases, systemic diseases and cancer have been reviewed. When possible, only comparative articles have been included (case-control studies mainly). When not, articles with poor methodology have been included. For each article, methodology and results are reported.