Urticaria Caused by Food Allergy True food allergies rarely cause urticaria in adults. Most cases occur in infants and children under age 3. Foods most commonly implicated include nuts, eggs, milk, shellfish, tomatoes, and strawberries. Hereditary angioedema is characterized by recurrent, self-limited attacks involving the skin and subcutaneous tissue of the upper respiratory and gastrointestinal tract. Patients with type 2 HAE have normal levels of C1 esterase inhibitor, but what is present is dysfunctional.
Urticarial lesions appear suddenly, wax and wane, and clear in a few hours.
Angioedema may last for 2 to 3 days. The diagnosis of urticaria requires a comprehensive history and thorough physical examination, with selected laboratory testing in some cases. History A history should include the description, duration, and location of lesions, associated symptoms, and known precipitating factors. Atopic patients may be prone to acute urticaria. Physical Examination Typical urticarial lesions are blanchable, wheal-like, erythematous, dermal swellings.