2026 ICD-10-CM Diagnosis Code J03.90Acute tonsillitis, unspecified

ICD-10-CM Codes›J00–J99›J00-J06›J03

ICD-10-CM J03.90
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

J03.90 is a billable ICD-10-CM diagnosis code for acute tonsillitis, unspecified. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 152 through 153. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Acute and chronic tonsillitis.

Code Identity

ICD-10-CM Code
J03.90
Billable Status
Yes — Valid for Submission
Code Describes
Acute tonsillitis, unspecified
Short Description
Acute tonsillitis, unspecified
Same as the full description in the CMS dataset.
Parent Code
J03.9
Acute tonsillitis, unspecified

Code Classification

ChapterJ00–J99Diseases of the respiratory system
SectionJ00-J06Acute upper respiratory infections
CategoryJ03Acute tonsillitis
This CodeJ03.90Acute tonsillitis, unspecified

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acute adenoiditis
  • Acute catarrhal tonsillitis
  • Acute erythematous tonsillitis
  • Acute follicular tonsillitis
  • Acute gangrenous pharyngitis
  • Acute gangrenous tonsillitis
  • Acute glossitis
  • Acute infection of tonsillar remnant
  • Acute infective adenoiditis
  • Acute lingual tonsillitis
  • Acute tonsillitis
  • Acute ulcerative pharyngitis
  • Acute ulcerative tonsillitis
  • Acute viral pharyngitis
  • Acute viral tonsillitis
  • Adenoiditis
  • Bacterial tonsillitis
  • Exudative pharyngitis
  • Follicular tonsillitis
  • Gangrenous pharyngitis
  • Gangrenous tonsillitis
  • Inflamed tonsils
  • Lingular tonsillitis
  • Pharyngotonsillitis
  • Suppurative tonsillitis
  • Tonsillitis
  • Ulcer of pharynx
  • Ulcer of tonsil
  • Ulcerative pharyngitis
  • Ulcerative tonsillitis
  • Viral tonsillitis

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.

    • Adenoiditis(chronic)
      • acute
    • Infection, infected, infective(opportunistic)
      • adenoid (and tonsil)
    • Tonsillitis(acute) (catarrhal) (croupous) (follicular) (gangrenous) (infective) (lacunar) (lingual) (malignant) (membranous) (parenchymatous) (phlegmonous) (pseudomembranous) (purulent) (septic) (subacute) (suppurative) (toxic) (ulcerative) (vesicular) (viral)

Clinical ClassificationClinical

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

CCSR RSP004
Acute and chronic tonsillitis
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Tonsillitis

    inflammation of the tonsils, especially the palatine tonsils but the adenoids (pharyngeal tonsils) and lingual tonsils may also be involved. tonsillitis usually is caused by bacterial infection. tonsillitis may be acute, chronic, or recurrent.

  • Acute Tonsillitis

    an acute inflammation of the tonsils caused by viruses or bacteria. signs and symptoms include fever, enlargement of the tonsils, difficulty swallowing, and enlargement of the regional lymph nodes.

  • Tonsillitis

    inflammation of the tonsillar tissue.

Patient EducationClinical

Tonsillitis

Tonsils are lumps of tissue at the back of the throat. There are two of them, one on each side. Along with the adenoids, tonsils are part of the lymphatic system. The lymphatic system clears away infection and keeps body fluids in balance. Tonsils and adenoids work by trapping the germs coming in through the mouth and nose.

The full article covers:

  • What are tonsils?
  • What is tonsillitis?
  • What causes tonsillitis?
  • Who is at risk for tonsillitis?
  • Is tonsillitis contagious?
  • What are the symptoms of tonsillitis?
  • When does my child need to see a health care provider for tonsillitis?
  • How is tonsillitis diagnosed?

Read the full article at MedlinePlus

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

Convert J03.90 to ICD-9-CMHistory

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

ICD-9-CM
463 Acute tonsillitis
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 J03.90Overview

Is J03.90 (Acute tonsillitis, unspecified) a billable code?

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

What MS-DRG does J03.90 group to?

When acute tonsillitis, unspecified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 152, 153, with relative weights from 0.7382 to 1.1822 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of J03.90?

Under the General Equivalence Mappings, acute tonsillitis, unspecified converts to ICD-9-CM 463 (acute tonsillitis). 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.