Urticaria (also called “nettle rash” or “hives”) is common and affects 20% of people at some point in their lives. The most common form is called spontaneous urticaria. Spontaneous urticaria is divided into “acute” and “chronic” forms dependent upon whether the episode lasts less than or greater than 6 weeks.

Omalizumab (Xolair) is a drug that interferes with natural antibodies called IgEs to prevent them from causing histamine release from certain cells in the body. It can improve urticaria and angioedema as histamine is responsible for hives and swellings.