Autoinflammatory syndromes (M04) ICD-10-CM
The M04 code range covers autoinflammatory syndromes with 6 ICD-10-CM diagnosis codes. 5 of them are billable and valid for claim submission in fiscal year 2027, and the category headers group them but cannot themselves be billed.
Type 2 Excludes
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
- Crohn's disease K50
Codes in the M04 Range 6 codes · 5 billable
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the M04 range.
Autoinflammatory Syndrome
A group of disorders of the innate immune system characterized by attacks of seemingly unprovoked inflammation without significant levels of either autoantibodies or autoreactive T cells more characteristic of autoimmune disease.
Cryopyrin-Associated Periodic Syndromes
A group of rare autosomal dominant diseases, commonly characterized by atypical URTICARIA (hives) with systemic symptoms that develop into end-organ damage. The atypical hives do not involve T-cell or autoantibody. Cryopyrin-associated periodic syndrome includes three previously distinct disorders: Familial cold autoinflammatory syndrome; Muckle-Wells Syndrome; and CINCA Syndrome, that are now considered to represent a disease continuum, all caused by NLRP3 PROTEIN mutations.
VEXAS Syndrome
An X-linked inherited condition caused by somatic mutation(s) in the UBA1 gene, encoding ubiquitin-like modifier-activating enzyme 1. It is characterized by the adult onset of rheumatologic symptoms in males, including recurrent fevers, pulmonary and dermatologic inflammatory manifestations, vasculitis, arthralgias, facial chondritis and hematologic abnormalities.
About the M04 Code Range
Periodic fever syndromes sit alongside cryopyrin-associated periodic syndromes and VEXAS syndrome.
Within M04, M04.1 identifies periodic fever syndromes, M04.2 identifies cryopyrin-associated periodic syndromes, and M04.3 identifies VEXAS syndrome. M04.8 covers other autoinflammatory syndromes, while M04.9 is for an unspecified autoinflammatory syndrome.
FY 2027 changes: The FY 2027 ICD-10-CM update, effective October 1, 2026, added M04.3.
Questions About This Page
How many billable codes are in the M04 range?
Of the 6 codes in this range, 5 are billable and valid for claim submission from October 1, 2026 through September 30, 2027. Category header codes group them but cannot be reported on claims.
What does the M04 range classify?
The range classifies autoinflammatory syndromes. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2027 ICD-10-CM Tabular List and order file, effective October 1, 2026 through September 30, 2027.
