ICD-10 Code G44.001 – Cluster headache syndrome, unspecified, intractable (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G44.001 – Cluster headache syndrome, unspecified, intractable
What it is
G44.001 identifies cluster headache syndrome when the type is not further specified and the headaches are intractable. It refers to a severe primary headache disorder with recurring attacks that are difficult to control.
Clinical signs
Typical features include repeated, severe unilateral head pain with autonomic symptoms such as tearing, nasal congestion, or eye redness. Clinical features vary; refer to documentation.
When to use this code
Use this code when the record documents cluster headache syndrome, but does not specify a subtype, and the provider states it is intractable. You should also use it when the diagnosis is clearly established and the chart supports persistence despite treatment. If the note does not confirm intractability, check documentation.
Do not use for
Do not use this code for migraine, tension-type headache, or other headache disorders. Also avoid it when the chart describes cluster headache without intractability or gives a more specific cluster headache code.
Coding tip
Confirm both elements in the note: unspecified cluster headache syndrome and intractable status.