Contact urticaria

This code represents an inflammatory skin reaction characterized by transient wheals, erythema, and itching that occurs upon direct contact with an external substance. Unlike allergic contact dermatitis, contact urticaria is typically an immediate hypersensitivity reaction, often mediated by IgE, or a non-immunologic reaction to irritants.

Assign this code when documentation specifies a diagnosis of contact urticaria, indicating a localized skin reaction to a specific contactant. This diagnosis is supported by a history of immediate skin changes following exposure and clinical examination revealing characteristic urticarial lesions at the contact site.

• Differentiate from allergic contact dermatitis (L23.-) which involves a delayed hypersensitivity reaction.
• Do not confuse with other forms of urticaria (e.g., L50.0 Allergic urticaria, L50.1 Idiopathic urticaria) unless contact is explicitly documented as the cause.
• Consider an additional code from Z88.- (Allergy status to drugs, medicaments, and biological substances) or Z91.0- (Allergy status to food, other antigenic substances) if the specific contactant is identified and relevant for patient management.