G44.81 – Hypnic headache

ICD-10-CM 2027 diagnosis code · Episodic and paroxysmal disorders

Billable code

ICD-10-CM code G44.81

Code: G44.81 (claims format: G4481)
Description: Hypnic headache
Billable: Yes – valid for HIPAA-covered transactions
Valid for: Dates of service October 1, 2026 – September 30, 2027 (FY2027)
Chapter: 6. Diseases of the nervous system (G00-G99)
Block: G40-G47 Episodic and paroxysmal disorders
Parent codes: G44 › G44.8

Notes inherited from parent codes

Instructional notes at a category or block level apply to every code below it.

G44 – Other headache syndromes

Excludes1 (not coded here):

headache NOS (R51.9)

Excludes2 (not included here):

atypical facial pain (G50.1)
headache due to lumbar puncture (G97.1)
migraines (G43.-)
trigeminal neuralgia (G50.0)

G44.8 – Other specified headache syndromes

Excludes2 (not included here):

headache with orthostatic or positional component, not elsewhere classified (R51.0)

Index terms for G44.81

Entries in the ICD-10-CM alphabetic index that lead to this code:

Headache, hypnic

Related codes in G44.8

G44.82 – Headache associated with sexual activityBillable
G44.83 – Primary cough headacheBillable
G44.84 – Primary exertional headacheBillable
G44.85 – Primary stabbing headacheBillable
G44.86 – Cervicogenic headacheBillable
G44.89 – Other headache syndromeBillable

Frequently asked questions

What is ICD-10 code G44.81?

G44.81 is the ICD-10-CM code for hypnic headache, in the block G40-G47 (Episodic and paroxysmal disorders).

Is G44.81 a billable code?

Yes. G44.81 is a billable/specific code that can be used to indicate a diagnosis for reimbursement purposes.

What category does G44.81 belong to?

It belongs to category G44 – Other headache syndromes.

Source: CDC/NCHS ICD-10-CM FY2027 code files, tabular list and index. Reference only – code assignment must follow the official ICD-10-CM guidelines and documentation in the medical record.