Idiopathic urticaria

This code represents chronic urticaria where the underlying cause cannot be identified despite thorough investigation. Patients experience recurrent episodes of hives (wheals) and often angioedema, lasting for more than six weeks, without an identifiable external trigger or associated systemic disease.

Use this code when documentation clearly states a diagnosis of idiopathic urticaria or chronic spontaneous urticaria. This diagnosis is typically made after other potential causes of urticaria, such as allergic reactions, physical stimuli, or autoimmune conditions, have been ruled out.

• Ensure documentation explicitly states "idiopathic" or "spontaneous" urticaria to support this specific code.
• Do not use this code if a specific cause for the urticaria has been identified (e.g., allergic, cold-induced).
• Consider sequencing this code as the primary diagnosis when it is the reason for the encounter.