Contact urticaria, defined as a wheal and flare reaction caused by direct contact with a protein or a low molecular weight chemical substance (hapten), may be caused by a wide variety of agents, and may be immunological (sensitization required) or nonimmunological (no sensitization required). The general population are increasingly exposed to a range of chemicals and products that have been demonstrated to induce hypersensitivity reactions. In medical settings, natural rubber latex and other substances previously caused contact urticaria frequently in clinical staff. Reactions to animal and vegetable products are also being increasingly recognized in occupational and domestic environments. Reactions secondary to cosmetics may be challenging because of the complexity in identifying the responsible substance as a number of cosmetics are often used concurrently with a number of possible agents capable of causing reactions. The correct diagnosis of contact urticaria and identification of the causative agent is extremely important. There is a potential effect on the patient’s ability to work in their chosen profession, or to enjoy leisure pursuits and domestic activities. In some situations, progression from a limited skin eruption to severe systemic involvement, including life-threatening anaphylaxis, is possible. A selection of interesting clinical cases examining the diagnostic procedures and subsequent management of contact urticaria is reviewed, with the aim of highlighting common and less common clinical presentations. This review will benefit clinicians handling complicated cases by increasing their awareness of existing reports, therefore aiding early identification, testing, and management.
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