ICD-10 Code L03.91 – Acute lymphangitis, unspecified (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code L03.91 – Acute lymphangitis, unspecified
What it is
L03.91 identifies acute lymphangitis when the affected lymphatic vessels are not further specified. Use it for a sudden infection or inflammation involving lymph channels, usually documented without a more exact site.
Clinical signs
Typical findings include linear red streaking extending from an infection site, local tenderness, and swollen lymph nodes. Clinical features vary; refer to documentation.
When to use this code
Use this code when the provider documents acute lymphangitis but does not specify the involved region or cause. It also fits cases where the record supports lymphatic inflammation, yet the documentation is limited. If another more specific diagnosis is recorded, code that instead.
Do not use for
Do not use it for chronic lymphatic disorders or for cellulitis without lymphatic involvement. Check documentation if the note describes a different infection site or a more specific lymphangitis code.
Coding tip
Query for the exact lymphatic site when the record says “acute lymphangitis” but gives no location.