2026 ICD-10-CM Diagnosis Code L03.90Cellulitis, unspecified

ICD-10-CM Codes›L00–L99›L00-L08›L03

ICD-10-CM L03.90
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

L03.90 is a billable ICD-10-CM diagnosis code for cellulitis, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 573 through 575, 602 through 603. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Skin and subcutaneous tissue infections.

Code Identity

ICD-10-CM Code
L03.90
Billable Status
Yes — Valid for Submission
Code Describes
Cellulitis, unspecified
Short Description
Cellulitis, unspecified
Same as the full description in the CMS dataset.
Parent Code
L03.9
Cellulitis and acute lymphangitis, unspecified

Code Classification

ChapterL00–L99Diseases of the skin and subcutaneous tissue
SectionL00-L08Infections of the skin and subcutaneous tissue
CategoryL03Cellulitis and acute lymphangitis
This CodeL03.90Cellulitis, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acute bacterial paronychia
  • Acute cellulitis
  • Bacterial cellulitis
  • Bacterial paronychia
  • Cellulitis
  • Cellulitis caused by Staphylococcus aureus
  • Cellulitis of digit
  • Cellulitis of skin
  • Cellulitis of skin with lymphangitis
  • Cellulitis with lymphangitis of digit
  • Chronic paronychia
  • Extensive postoperative wound cellulitis
  • Gram-negative bacterial cellulitis
  • Haemophilus cellulitis
  • Injection site cellulitis
  • Injection site inflammation
  • Mucormycotic gangrenous cellulitis
  • Necrotizing cellulitis
  • Onychia
  • Paronychia
  • Postoperative wound cellulitis
  • Pseudomonas aeruginosa infection of nail
  • Pseudomonas aeruginosa paronychia
  • Recurrent cellulitis
  • Streptococcal cellulitis
  • Traumatic onychia
  • Vaccination site cellulitis
  • Wound cellulitis

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Cellulitis(diffuse) (phlegmonous) (septic) (suppurative)
    • Cellulitis(diffuse) (phlegmonous) (septic) (suppurative)
      • chronic
    • Cellulitis(diffuse) (phlegmonous) (septic) (suppurative)
      • multiple sites, so stated

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR SKN001
Skin and subcutaneous tissue infections
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Cellulitis

    an acute, diffuse, and suppurative inflammation of loose connective tissue, particularly the deep subcutaneous tissues, and sometimes muscle, which is most commonly seen as a result of infection of a wound, ulcer, or other skin lesions.

  • Orbital Cellulitis

    inflammation of the loose connective tissues around the orbit, bony structure around the eyeball. it is characterized by pain; edema of the conjunctiva; swelling of the eyelids; exophthalmos; limited eye movement; and loss of vision.

  • Parametritis

    inflammation of the parametrium, the connective tissue of the pelvic floor, extending from the subserous coat of the uterus laterally between the layers of the broad ligament.

  • Paronychia

    an inflammatory reaction involving the folds of the skin surrounding the fingernail. it is characterized by acute or chronic purulent, tender, and painful swellings of the tissues around the nail, caused by an abscess of the nail fold. the pathogenic yeast causing paronychia is most frequently candida albicans. saprophytic fungi may also be involved. the causative bacteria are usually staphylococcus, pseudomonas aeruginosa, or streptococcus. (andrews' diseases of the skin, 8th ed, p271)

  • Broad Ligament

    a broad fold of peritoneum that extends from the side of the uterus to the wall of the pelvis.

  • Grade 2 Paronychia, CTCAE|Grade 2 Paronychia

    local intervention indicated; oral intervention indicated (e.g., antibiotic, antifungal, antiviral); nail fold edema or erythema with pain; associated with discharge or nail plate separation; limiting instrumental adl or mild/moderate impact on age-appropriate normal daily activity (pediatric)

  • Grade 3 Paronychia, CTCAE|Grade 3 Paronychia

    operative intervention indicated; iv antibiotics indicated; limiting self-care adl or severe impact on age-appropriate normal daily activity (pediatric)

  • Grade 1 Paronychia, CTCAE|Grade 1 Paronychia

    nail fold edema or erythema; disruption of the cuticle

  • Grade 2 Paronychia, CTCAE|Grade 2 Paronychia

    local intervention indicated; oral intervention indicated (e.g., antibiotic, antifungal, antiviral); nail fold edema or erythema with pain; associated with discharge or nail plate separation; limiting instrumental adl

  • Grade 3 Paronychia, CTCAE|Grade 3 Paronychia

    operative intervention indicated; iv antibiotics indicated; limiting self care adl

  • Paronychia

    an acute or chronic infection of the soft tissues around the nail. symptoms include pain, tenderness, erythema, and swelling around the nail. acute infection results from minor trauma to the fingertip and staphylococcus aureus is usually the causative agent. chronic infection is usually caused by candida albicans.

  • Paronychia, CTCAE|Paronychia|Paronychia

    a disorder characterized by an infectious process involving the soft tissues around the nail.

  • Paronychial Inflammation

    swelling and redness of the nail folds.

Patient EducationClinical

Cellulitis

Cellulitis is an infection of the skin and deep underlying tissues. Group A strep (streptococcal) bacteria are the most common cause. The bacteria enter your body when you get an injury such as a bruise, burn, surgical cut, or wound.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert L03.90 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
682.9 Cellulitis NOS
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About L03.90Overview

Is L03.90 (Cellulitis and acute lymphangitis, unspecified) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report cellulitis, unspecified on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does L03.90 group to?

When cellulitis, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 573, 574, 575, 602, 603, with relative weights from 0.8709 to 6.5514 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of L03.90?

Under the General Equivalence Mappings, cellulitis, unspecified converts to ICD-9-CM 682.9 (cellulitis NOS). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.