Table 1 Definition of chronic spontaneous urticaria and urticarial vasculitis

Chronic spontaneous urticaria

 Spontaneous development of wheals, angioedema, or both for > 6 weeks. Wheals have the following characteristics

  1. Central swelling surrounded by reflex erythema.

  2. Itching, sometimes burning sensation

  3. Skin returning to normal appearance within 30 min to 24 h

Urticarial vasculitis

 Clinical manifestations of urticaria characterized by wheals that are painful, burning, and tender in sensation. Lesions tend to last > 24 h and are associated with faint residual hyperpigmentation. Biopsy is needed to confirm the diagnosis, with the following findings

  1. Inflammatory injury to capillaries and postcapillary venules

  2. Leukocytoclasis with fibrinoid deposits as signs of direct vessel damage