Corrosion of third degree of unsp thumb (nail), sequela

This code signifies a deep tissue injury to an unspecified thumb, resulting from chemical or electrical exposure, where the full thickness of the skin and underlying tissues have been destroyed. The "sequela" indicator denotes that this code is used for complications or conditions arising directly from the initial corrosion, after the acute phase of the injury has passed.

This code is appropriate for documenting long-term effects, scarring, contractures, or functional impairments of the thumb that are a direct consequence of a third-degree corrosion. It should be used for follow-up encounters when the patient is being treated for these residual conditions, not for the initial acute injury.

• Always assign an external cause code (V00-Y99) to describe the circumstances of the corrosion.
• Ensure documentation clearly specifies "third degree" and "corrosion" to differentiate from thermal burns.
• The "S" seventh character indicates sequela; do not use for active or acute treatment of the initial injury.