L04

ICD-10Non-billable category

Acute lymphadenitis

Official ICD-10-CM descriptor (FY2026)

Acute lymphadenitis

L04 is a category heading, not a billable code. CMS does not accept it on a claim; report one of the more specific codes beneath it.

Includes

  • abscess (acute) of lymph nodes, except mesenteric
  • acute lymphadenitis, except mesenteric

Excludes1

Not coded here. An Excludes1 code should never be reported at the same time as the code above it.

  • chronic or subacute lymphadenitis, except mesenteric (I88.1)
  • enlarged lymph nodes (R59.-)
  • human immunodeficiency virus [HIV] disease resulting in generalized lymphadenopathy (B20)
  • lymphadenitis NOS (I88.9)
  • nonspecific mesenteric lymphadenitis (I88.0)

More specific codes under L04

Where this code sits

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Source

ICD-10-CM FY2026. Centers for Medicare & Medicaid Services (CMS) / National Center for Health Statistics (NCHS), “2026 ICD-10-CM Code Descriptions in Tabular Order” (icd10cm_order_2026.txt). Download the original file from cms.gov. Public domain (US Government work). Descriptors, billable flags and instructional notes on this page are reproduced from that file without modification. Krasyn adds no clinical guidance.

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