Allergic urticaria

This code represents an acute or chronic skin condition characterized by the sudden appearance of itchy, raised welts (hives) or wheals, which are a direct immune response to an allergen. The reaction involves the release of histamine and other mediators, leading to localized edema and erythema.

Use this code when documentation clearly indicates urticaria caused by an allergic reaction, such as to food, medication, insect stings, or environmental allergens. Supporting documentation should specify the allergic etiology, often noted as "allergic urticaria," "hives due to allergy," or "urticarial rash, allergic origin."

• Distinguish from urticaria due to physical causes (e.g., cold, pressure) or idiopathic urticaria, which have different codes.
• If the specific allergen is identified, consider coding it as an additional diagnosis (e.g., adverse effect of drug, food allergy).
• Ensure the documentation explicitly states "allergic" to justify using this specific code over a more general urticaria code.