ICD-10 Code J03 – Acute tonsillitis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code J03 – Acute tonsillitis
What it is
J03 identifies acute inflammation of the tonsils. Use it for a new, short-term tonsillar infection or irritation documented as acute tonsillitis.
Clinical signs
Typical findings include sore throat, enlarged or erythematous tonsils, and pain with swallowing. Fever, tonsillar exudate, and tender cervical nodes may be present; clinical features vary, so refer to documentation.
When to use this code
Use J03 when the provider documents acute tonsillitis without a more specific subtype. It may also fit cases described as tonsillitis, acute pharyngotonsillitis, or tonsillar infection when the record supports an acute process. Check documentation if the note distinguishes recurrent, chronic, or peritonsillar disease.
Do not use for
Do not use J03 for chronic or recurrent tonsillitis, which are coded separately. Avoid it when the documentation is for peritonsillar abscess, pharyngitis alone, or another more specific diagnosis.
Coding tip
Code the most specific tonsil diagnosis documented, and query the provider if the record only says “sore throat” or does not clearly state acute tonsillitis.