Autoinflammatory syndromes (M04) ICD-10-CM
The M04 code range covers autoinflammatory syndromes with 5 ICD-10-CM diagnosis codes. 4 of them are billable and valid for claim submission in fiscal year 2026, 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 5 codes · 4 billable
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the M04 range.
Familial Mediterranean Fever
A group of HEREDITARY AUTOINFLAMMATION DISEASES, characterized by recurrent fever, abdominal pain, headache, rash, PLEURISY; and ARTHRITIS. ORCHITIS; benign MENINGITIS; and AMYLOIDOSIS may also occur. Homozygous or compound heterozygous mutations in marenostrin gene encoding PYRIN result in autosomal recessive transmission; simple heterozygous, autosomal dominant form of the disease also exists with mutations in the same gene.
Macrophage Activation Syndrome
A serious complication of childhood systemic inflammatory disorders that is thought to be caused by excessive activation and proliferation of T-LYMPHOCYTES and MACROPHAGES. It is seen predominantly in children with systemic onset JUVENILE IDIOPATHIC ARTHRITIS.
About the M04 Code Range
The M04 ICD-10 codes cover a group of conditions known as autoinflammatory syndromes, which are disorders characterized by episodes of inflammation without the usual triggers like infections or autoimmunity. These codes classify specific syndromes involving periodic fevers, cold-induced symptoms, and other complex inflammatory disorders.
Within this range, M04.1 refers to periodic fever syndromes, also known colloquially as familial Mediterranean fever, PFAPA syndrome, or TNF receptor-associated periodic fever syndrome (TRAPS). These conditions feature recurrent fever episodes and inflammation. Code M04.2 covers cryopyrin-associated periodic syndromes, including familial cold urticaria and chronic infantile neurological, cutaneous, and articular syndrome, where symptoms are triggered by cold exposure. The M04.8 category includes other autoinflammatory syndromes such as Blau syndrome, VEXAS syndrome, and Majeed syndrome, encompassing diverse hereditary and monogenic inflammatory disorders. Lastly, M04.9 is used for unspecified autoinflammatory syndromes when a precise diagnosis within these categories is not established. These codes help clearly identify and track various autoinflammatory diseases for accurate diagnosis and management.
Questions About This Page
How many billable codes are in the M04 range?
Of the 5 codes in this range, 4 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. 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 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
