**5. Clinical features**

with dissatisfaction in private life and work being frequent [4]. Non-sedating H<sup>1</sup>

measures and treatment of acute attacks [5].

12 A Comprehensive Review of Urticaria and Angioedema

**2. Classification**

this chapter.

**3. Epidemiology**

mines are the first line therapy for both acute and chronic urticaria. Apart from angioedema which is part of the spectrum of urticaria, there is bradykinin-induced angioedema, such as that observed in the hereditary angioedema characterized by angioedema without wheals. Management of isolated angioedema differs from that of urticaria involving both preventive

The current classification of urticaria is based upon the clinical course of the disease. Subtypes include spontaneous urticaria, physical urticarias and other urticaria types [2]. Spontaneous urticaria can either be acute lasting less than 6 weeks or chronic with a duration of more than 6 weeks. This arbitrary division for chronicity has been made as the etiologies and thus the clinical evaluation of acute and chronic urticaria vary considerably [3]. The physical and other urticaria types are elicited by external stimuli, such as heat, cold, pressure, vibration, friction, sunlight, water, etc. [6]. These two subtypes of urticaria are beyond the scope of

An episode of urticaria can occur in 15–25% of individuals at some point in their lifetime. Approximately 40% of patients with urticaria have wheals associated with angioedema and 1–13% of patients present with isolated angioedema [3, 7]. Socioeconomic status, ethnicity

At first all cases of urticaria are acute; 30% of them progress to become chronic [7]. Acute episodic form of urticaria commonly presents in infancy and childhood, particularly in atopic subjects [1, 8]. Chronic urticaria peaks in adulthood between 20 and 40 years of age affecting women two times more frequently than men [1, 3, 4]. About 0.5–1% of population has chronic

Drugs, foods, viral and parasitic infections, insect stings and contact allergens are present among the most common causes of acute urticaria [8]. Drugs most commonly implicated in acute urticaria are antibiotics (penicillins and sulfonamides), nonsteroidal anti-inflammatory drugs, acetylsalicylic acid, opiates and narcotics. Foods, such as milk, eggs, nuts, fish and shellfish are common offenders, as well as food additives, such as tartrazine dyes, benzoic acid derivatives like sodium benzoate. Approximately 50% of cases of acute urticaria are

and education do not have any clear influence on the prevalence of the disease [3].

spontaneous urticaria at a specific point in time [3].

**4. Etiology and pathogenesis**

idiopathic [5, 9].

antihista-

Urticarial wheals consist of circumscribed erythematous plaques of various sizes with central swelling, with or without a surrounding flare (**Figure 1**). There is accompanying intense pruritus or occasional burning sensations. Lesions typically have round to oval shape but occasionally irregular, serpiginous or gyrate configurations may occur. Wheals are blanchable by diascopy. Individual lesions usually disappear within 1–24 hours without scarring but some lesions may take up to 48 hours to resolve [14–16]. Patients often report a poorly localized pruritus starting before the appearance of wheals [7]. Pruritus may impair sleep, private life and work leading to a diminished quality of life [4].

Angioedema is a descriptive term for abrupt onset of swellings of the deep dermis and subcutaneous tissue. In contrast to edema, angioedema is asymmetrical and can occur on nondependent sites. Most common sites of involvement are the lips (**Figure 2**), tongue, eyelids and genitalia although any part of the body can be involved. Due to the tissue distention, the lesions are usually painful rather than pruritic. Swellings of angioedema can be pink or skin-colored [9, 17, 18]. Involvement of the mucous membranes is a common feature. Stridor, abdominal pain, rarely intestinal obstruction may result from edema of respiratory or gastrointestinal tract. Lesions may take up to 72 hours to resolve [9, 18].

**Figure 1.** Typical urticarial plaques are observed on the leg of the patient.

**Figure 2.** Angioedema involving the lips.
