ICD-10 Code I87.029 – Postthrombotic syndrome with inflammation of unspecified lower extremity (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code I87.029 – Postthrombotic syndrome with inflammation of unspecified lower extremity
What it is
I87.029 identifies postthrombotic syndrome affecting an unspecified lower extremity with inflammation. It describes chronic venous problems that develop after a prior deep vein thrombosis, with inflammatory changes documented in the leg.
Clinical signs
Typical findings include chronic leg pain, swelling, heaviness, skin discoloration, and venous stasis changes. Clinical features vary; refer to documentation for evidence of inflammation and the affected lower extremity.
When to use this code
Use this code when the record clearly links the patient’s lower-extremity symptoms to postthrombotic syndrome and notes inflammation. It is appropriate when the side is not specified or documentation supports an unspecified lower extremity. Check documentation if the diagnosis is only historical or if another venous disorder is the primary reason for the visit.
Do not use for
Do not use this code for acute deep vein thrombosis, simple leg edema, or venous insufficiency without postthrombotic syndrome. If inflammation is not documented, or the affected limb is specified elsewhere, choose the more accurate code.
Coding tip
Verify both the postthrombotic syndrome and inflammation are documented before assigning I87.029.