ICD-10 Code G44.02 – Chronic cluster headache (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G44.02 – Chronic cluster headache
What it is
G44.02 identifies chronic cluster headache, a primary headache disorder with repeated cluster attacks over time. Use it when documentation specifies the chronic pattern rather than an episodic form.
Clinical signs
Clinical features vary; refer to documentation. Standard references describe severe unilateral headache attacks with autonomic symptoms such as tearing, nasal congestion, or eyelid changes.
When to use this code
Use G44.02 when the provider documents chronic cluster headache, including ongoing or recurrent cluster periods without long remission. It also fits follow-up visits when the diagnosis is established and still active. If the note only says “cluster headache,” check whether chronic or episodic is specified.
Do not use for
Do not use this code for episodic cluster headache or for nonspecific headache diagnoses. If the record does not clearly support chronic cluster headache, check documentation before coding.
Coding tip
Confirm the word “chronic” in the assessment or problem list before assigning G44.02.