Alphabetic Index FY2027

L03.91

Acute lymphangitis, unspecified

FY2027Chapter 12: Diseases of the skin and subcutaneous tissue/L00–L08 Infections of the skin and subcutaneous tissue

BillableComplete code, valid to report
Care settingsHospital CC

L03.91 (also written L0391) is a billable ICD-10-CM diagnosis code for acute lymphangitis, unspecified. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 55 codes in category L03 (Cellulitis and acute lymphangitis). The Alphabetic Index lists it under 1 entry. Its coding notes include a Use additional code instruction, 1 Excludes1 entry and 34 Excludes2 entries.

Use additional code

Add the listed code as a secondary code, if known.

Also from chapter/block level (1 note)
Inherited from L00–L08 Infections of the skin and subcutaneous tissue
  • code (B95-B97) to identify infectious agent.

Excludes1

Not coded here. The listed conditions generally should not be reported together.

This code

Excludes2

Not included here. Both codes may be reported if the patient has both conditions.

Inherited from L03 Cellulitis and acute lymphangitis
  • cellulitis of anal and rectal region (K61.-)
  • cellulitis of external auditory canal (H60.1)
  • cellulitis of eyelid (H00.0)
  • cellulitis of female external genital organs (N76.4)
  • cellulitis of lacrimal apparatus (H04.3)
  • cellulitis of male external genital organs (N48.2, N49.-)
  • cellulitis of mouth (K12.2)
  • cellulitis of nose (J34.0)
  • eosinophilic cellulitis [Wells] (L98.3)
  • febrile neutrophilic dermatosis [Sweet] (L98.2)
  • lymphangitis (chronic) (subacute) (I89.1)
Also from chapter/block level (23 notes)
Inherited from L00–L08 Infections of the skin and subcutaneous tissue
  • hordeolum (H00.0)
  • infective dermatitis (L30.3)
  • local infections of skin classified in Chapter 1
  • lupus panniculitis (L93.2)
  • panniculitis NOS (M79.3)
  • panniculitis of neck and back (M54.0-)
  • Perlèche NOS (K13.0)
  • Perlèche due to candidiasis (B37.0)
  • Perlèche due to riboflavin deficiency (E53.0)
  • pyogenic granuloma (L98.0)
  • relapsing panniculitis [Weber-Christian] (M35.6)
  • viral warts (B07.-)
  • zoster (B02.-)
Inherited from Chapter 12 Diseases of the skin and subcutaneous tissue
  • certain conditions originating in the perinatal period (P04-P96)
  • certain infectious and parasitic diseases (A00-B99)
  • complications of pregnancy, childbirth and the puerperium (O00-O9A)
  • congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
  • endocrine, nutritional and metabolic diseases (E00-E88)
  • lipomelanotic reticulosis (I89.8)
  • neoplasms (C00-D49)
  • symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
  • systemic connective tissue disorders (M30-M36)
  • viral warts (B07.-)

Care settings

How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.

Hospital CC

Counts as a complication or comorbidity (CC) when reported as a secondary diagnosis on an inpatient claim. It does not count when the principal diagnosis is one of the 43 codes in its exclusion list. Some MS-DRGs also ignore a CC or MCC that defines the DRG.

Source: CMS MS-DRG Definitions Manual v44, effective October 1, 2026, Appendix C

Alphabetic Index terms

Terms the official Alphabetic Index lists for this code. 1 entry