ICD-10 Code G44.51 – Hemicrania continua (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G44.51 – Hemicrania continua
What it is
Hemicrania continua is a primary headache disorder with continuous, one-sided head pain. It is classically associated with autonomic symptoms and a marked response to indomethacin.
Clinical signs
Typical findings include persistent unilateral headache with periods of worsening, often with tearing, nasal congestion, or eyelid changes on the same side. Clinical features vary; refer to documentation.
When to use this code
Use G44.51 when the provider documents hemicrania continua, or a clearly diagnosed continuous unilateral headache consistent with this disorder. You should code it only when the diagnosis is established, not for nonspecific headache symptoms. Check documentation if the chart does not explicitly support the condition.
Do not use for
Do not use this code for migraine, cluster headache, tension-type headache, or unspecified chronic headache. If the record only says “headache” without a confirmed diagnosis, choose a more specific documented code.
Coding tip
Look for the exact provider diagnosis and supporting note of unilateral continuous pain, then verify that hemicrania continua is stated.