Blister (nonthermal) of nose, initial encounter

This code signifies a non-burn-related fluid-filled lesion on the external nose. It indicates the initial presentation or active treatment phase of such a blister, which may arise from various causes other than heat or chemical exposure.

Apply this code when documentation specifies a blister on the nose that is explicitly not due to thermal or chemical injury, and the patient is receiving initial active treatment for the condition. This includes scenarios like allergic reactions, friction, or certain dermatological conditions manifesting as blisters on the nose.

• Ensure documentation clearly states "nonthermal" or specifies a non-burn etiology for the nasal blister.
• Verify the encounter is for initial treatment; subsequent encounters would use a different seventh character.
• Distinguish from S00.31XA (abrasion) or S00.35XA (superficial foreign body) of the nose, as these involve different types of skin injury.