ICD-10 Code G44.81 – Hypnic headache (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G44.81 – Hypnic headache
What it is
G44.81 identifies hypnic headache, a rare primary headache disorder that occurs only during sleep. It is sometimes called an “alarm clock” headache because it wakes the person at a fairly regular time.
Clinical signs
Typical features include recurrent headaches that begin during sleep and cause awakening, often in older adults. Clinical features vary; refer to documentation for laterality, duration, frequency, and associated symptoms.
When to use this code
Use G44.81 when the provider documents hypnic headache by name or clearly describes a sleep-related headache pattern consistent with this diagnosis. Apply it when the headache is the primary documented condition and not better explained by another disorder. Check documentation if the note also suggests migraine, cluster headache, or another secondary cause.
Do not use for
Do not use this code for general insomnia, nonspecific nighttime headaches, or headaches with an identified secondary cause. If the record does not support hypnic headache specifically, check documentation.
Coding tip
Code G44.81 only when the documentation clearly links the headache to sleep and names hypnic headache or an equivalent diagnosis.