Presented at Allergy/Immunology Community Hospital Outreach Program, November 2005 Chronic Urticaria:

Urticaria and angioedema affects 15 % to25 % of the population at some point in their lives. There are various causes for urticaria and angioedema (Figure 3). Urticarial vasculitis and urticaria pigmentosa are rare conditions (Table 1) but should be differentiat-ed from urticaria. Diagnosis of these conditions is made by a biopsy. Chronic urticaria More than six weeks of daily urticaria has been arbitrarily chosen to distinguish chronic urticaria from acute urticaria. Chronic urticaria will affect up to 3 % of the population at some point in their lives. The incidence of chronic urticaria is not increased in people with atopy. Females are more affected than males by a ratio of four to one. Physical urticarias Physical urticarias are conditions, such as der-matographism, in which physical pressure on the skin causes urticarial rashes to occur. Urticarial lesions are often linear, following scratch marks. Cholinergic urticaria is identi-fied by small papular urticarial lesions that tend to occur with: • heat, • exertion, or • emotional stress. Physical urticarias have lesions that usually last less than two hours. Izzy’s Itch • Izzy, 34, presents with daily hives for two months (Figures 1 and 2) • Individual lesions last six hours to 12 hours and are quite pruritic • Lesions are exacerbated by scratching • She has had some episodes of lip and periorbital swelling • Eliminating various foods from her diet has not resulted in any improvement • She has been using diphenhydramine intermittently and finds it somewhat helpful, but quite sedating For more on Izzy, go to page 69