Blister (nonthermal) of anus, sequela

This code signifies a non-thermal blister formation specifically located on the anus, indicating a long-term or residual effect of a previous injury or condition. It represents a skin lesion characterized by a fluid-filled sac, not caused by heat or cold exposure, that has persisted or developed as a consequence of an earlier event.

This code is appropriate for documenting a patient presenting with an anal blister that is clearly identified as a sequela, meaning it is a late effect of an initial injury or disease process. Examples include blisters arising years after a traumatic anal injury, a resolved infection, or a previous dermatological condition affecting the perianal area.

• Ensure documentation clearly supports the "sequela" nature of the blister, indicating it's a residual effect rather than an acute event.
• Verify the blister is explicitly stated as non-thermal; if thermal, a different code would be appropriate.
• Always code the underlying cause of the sequela if known and still relevant to the patient's care.