Blister (nonthermal) of lip, sequela

This code signifies a non-thermal blister on the lip that is a residual effect or complication of a previous injury or condition. It indicates a persistent or late-appearing manifestation of an earlier insult, rather than an acute event.

Use this code when documentation clearly states a blister on the lip is a long-term consequence of a prior non-thermal injury, such as a chemical burn, allergic reaction, or trauma, and is no longer in the acute phase. This code requires the "S" seventh character, indicating a sequela.

• Ensure documentation specifies the blister is a sequela and not an acute condition.
• Do not use for acute blisters; those would typically be coded with an "A" (initial encounter) or "D" (subsequent encounter) seventh character.
• Always sequence this code after the code for the underlying condition or external cause if known and still relevant.