ABSTRACT
Urticaria (hives) are lesions that are typically edematous with pale raised round or oval centers (wheals), of varying size and may occur anywhere on the body (Fig. 20.1). The area surrounding the wheal is commonly erythematous but well circumscribed and blanches with pressure. Urticaria may coalesce and thus create an appearance of irregular margins, but remain well defi ned. The lesions are transient in duration, lasting minutes to days and resolve without inherent scar or dyspigmentation. Typical lesions are markedly pruritic and are not associated with pain or burning sensation.1-4 Atypical urticaria lesions can be nonblanching, burning in character, last more than 24 hours and leave residual dyspigmentation or scar formation. These may represent vasculitic disease and warrant further evaluation.5 The majority of urticaria cases are acute with isolated outbreaks or with daily or almost daily recurrent hives for durations of less than 6 weeks. However, in as many as 30 percent of patients, lesions continue to occur for longer than 6 weeks and are defi ned as chronic.3,6-8
Angioedema is non-pitting edema and accompanies approximately 40 percent of urticaria cases. The edema occurs in the deep dermis and subcutaneous. These areas of angioedema may be of normal skin coloration or erythematous and are not typically associated with pruritis but may have the sensation of pressure, aching or burning. The distribution of angioedema is varied when occurring in conjunction with or independent of urticaria but is often in areas of pressure such as under the waistband. However, angioedema without
1Director, University of Colorado Hospital Allergy, Asthma, and Immunology Practice, Division of Allergy and Clinical Immunology, University of Colorado Denver. Aurora, Colorado USA. 2Allergist & Immunologist, 102 Westlake Drive, Suite 104, Austin, TX. 78746 USA. *Corresponding author
visible urticaria is unusual and involves a specifi c differential diagnosis as will be discussed separately below. Angioedema without urticaria affects approximately 10 percent of patients and often involves non-central regions such as the face, tongue, throat, extremities and genitals.3 The terms urticaria and urticaria/angioedema are used interchangeably within this chapter but the term angioedema refers to angioedema without associated urticaria.
