How is history of urticaria?

Information regarding history of previous urticaria and duration of rash and itching is useful for categorizing urticaria (with or without angioedema) as acute or chronic; Acute urticaria– Urticaria that recurs within a period of less than six weeks is acute (can be allergic) or Chronic urticaria –in rarer cases, where the rash comes and goes or persists for more than 6 weeks, often over many years