Blister (nonthermal) of unspecified forearm, sequela

This code signifies a non-burn related blister that has developed on an unspecified forearm, indicating a long-term or late effect of an initial injury or condition. It is used when the acute phase of the original injury has passed, and the blister is a residual complication.

Apply this code when documenting a chronic or persistent blister on the forearm where the specific side (left or right) is not documented, and the blister is a sequela of a previous, non-thermal event. This is appropriate for follow-up encounters addressing the lasting effects of an old injury.

• Always assign an external cause code (V00-Y99) to describe the original cause of the blister, if known.
• Ensure the documentation clearly states "sequela" or indicates a chronic/late effect to justify the 7th character 'S'.
• Avoid using this code for acute blisters; instead, select an acute injury code from the S50 category.