ICD-10 Code for Tonsillitis

The default ICD-10-CM 2027 code for tonsillitis (acute) (catarrhal) (croupous) (follicular) (gangrenous) (infective) (lacunar) (lingual) (malignant) (membranous) (parenchymatous) (phlegmonous) (pseudomembranous) (purulent) (septic) (subacute) (suppurative) (toxic) (ulcerative) (vesicular) (viral) is J03.90 – Acute tonsillitis, unspecified. More specific codes depend on the details documented, as listed in the official index (11 codes, 11 billable).

Main code: J03.90 – Acute tonsillitis, unspecified
Billable: Yes

Index entries for Tonsillitis

chronic – J35.01
- with adenoiditis – J35.03
diphtheritic – A36.0
hypertrophic – J35.01
- with adenoiditis – J35.03
recurrent – J03.91
specified organism NEC – J03.80
- recurrent – J03.81
staphylococcal – J03.80
- recurrent – J03.81
streptococcal – J03.00
- recurrent – J03.01
tuberculous – A15.8
Vincent's – A69.1

How to choose the right code

Start with the main term, then pick the indented subterm that matches the documentation (type, cause, site, laterality, episode of care). Always confirm the code in the tabular list: follow its Excludes1/Excludes2, “code first” and “use additional code” notes, and add a 7th character where required.

Source: CDC/NCHS ICD-10-CM FY2027 alphabetic index.