ICD-10 Code M04.2 – Cryopyrin-associated periodic syndromes (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code M04.2 – Cryopyrin-associated periodic syndromes
What it is
M04.2 identifies cryopyrin-associated periodic syndromes, a group of rare autoinflammatory disorders caused by abnormal innate immune activation. Use it when the record documents CAPS rather than a broader periodic fever condition.
Clinical signs
Clinical features vary; refer to documentation. Commonly reported findings include recurrent fever, rash, joint pain, eye inflammation, and other inflammatory episodes that begin in childhood or persist over time.
When to use this code
Use M04.2 when the clinician specifically documents cryopyrin-associated periodic syndrome, including recognized CAPS subtypes, and the diagnosis is the reason for the encounter. You may also use it when the chart clearly links ongoing inflammatory symptoms to CAPS. Check documentation if the note only says periodic fever, autoinflammatory syndrome, or suspected CAPS.
Do not use for
Do not use this code for nonspecific fever, isolated rash, or joint symptoms without a documented CAPS diagnosis. Also avoid it when another defined autoinflammatory or rheumatologic condition is recorded instead.
Coding tip
Code M04.2 only when the provider names CAPS or a specific CAPS subtype in the assessment.