ICD-10 Code G44.01 – Episodic cluster headache (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G44.01 – Episodic cluster headache
What it is
G44.01 identifies episodic cluster headache, a primary headache disorder with attacks that occur in clusters separated by remission periods. Use this code when the diagnosis is specifically documented as episodic cluster headache.
Clinical signs
Typical features include severe unilateral orbital, supraorbital, or temporal pain with autonomic symptoms such as tearing, nasal congestion, or eyelid droop. Clinical features vary; refer to documentation.
When to use this code
Use G44.01 when the provider documents episodic cluster headache, including follow-up visits for a known diagnosis. It also fits encounters where the chart clearly states the cluster pattern is episodic rather than chronic. If the record only says “cluster headache,” check documentation.
Do not use for
Do not use this code for chronic cluster headache or other headache types such as migraine or tension-type headache. If the subtype is unclear, check documentation.
Coding tip
Code the documented cluster subtype exactly; episodic and chronic cluster headache are different ICD-10-CM codes.