ICD-10 Code for Mastitis

The default ICD-10-CM 2027 code for mastitis (acute) (diffuse) (nonpuerperal) (subacute) is N61.0 – Mastitis without abscess. More specific codes depend on the details documented, as listed in the official index (11 codes, 8 billable).

Main code: N61.0 – Mastitis without abscess
Billable: Yes

Index entries for Mastitis

with abscess – N61.1
chronic (cystic) – see Mastopathy, cystic
cystic (Schimmelbusch's type) – see Mastopathy, cystic
fibrocystic – see Mastopathy, cystic
granulomatous – N61.2- (header)
infective – N61.0
- newborn – P39.0
interstitial, gestational or puerperal – see Mastitis, obstetric
neonatal (noninfective) – P83.4
- infective – P39.0
obstetric (interstitial) (nonpurulent)
- associated with
  - lactation – O91.23
  - pregnancy – O91.21- (header)
  - puerperium – O91.22
- purulent
  - associated with
    - lactation – O91.13
    - pregnancy – O91.11- (header)
    - puerperium – O91.12
periductal – see Ectasia, mammary duct
phlegmonous – see Mastopathy, cystic
plasma cell – see Ectasia, mammary duct
without abscess – N61.0

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.