ICD-10 Code L04 – Acute lymphadenitis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code L04 – Acute lymphadenitis
What it is
ICD-10 code L04 identifies acute inflammation of lymph nodes, usually from a nearby infection. Use it when the record documents sudden, painful lymph node swelling.
Clinical signs
Typical findings include enlarged, tender lymph nodes, sometimes with redness or warmth over the area. Clinical features vary; refer to documentation.
When to use this code
Use L04 when the provider documents acute lymphadenitis as the diagnosis and does not specify a more exact site or cause. It may apply to localized node inflammation related to an infection in the drainage area. Check documentation if the note describes chronic, generalized, or malignant lymph node disease instead.
Do not use for
Do not use this code for chronic lymphadenitis, lymphadenopathy without inflammation, or enlarged nodes due to malignancy. Check documentation for the correct condition.
Coding tip
Confirm the lymph node site and any documented underlying infection before assigning the most specific code available.