ICD-10-CM 2027 diagnosis code
G44.5Complicated headache syndromes
G44.5 is a header code, so it can't be reported by itself. Choose one of the 4 more specific codes beneath it.
Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data
About G44.5
G44.5 is the ICD-10-CM diagnosis code for complicated headache syndromes. It belongs to category G44 (other headache syndromes), block G40-G47 (episodic and paroxysmal disorders) and chapter 6 (diseases of the nervous system). It is a header code, so it can't be reported by itself; one of its 4 subcodes must be used instead.
Within G44 (other headache syndromes), G44.5 is specifically for complicated headache syndromes. Related codes cover cluster headaches and other trigeminal autonomic cephalgias (TAC) (G44.0), vascular headache, not elsewhere classified (G44.1), tension-type headache (G44.2), post-traumatic headache (G44.3), drug-induced headache, not elsewhere classified (G44.4) and other specified headache syndromes (G44.8).
To report this condition, pick the subcode that matches the documentation: G44.51 (continua), G44.52 ((NDPH)), G44.53 (headache) and G44.59 (syndrome).
It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.
Specific codes under G44.5
Notes that apply from higher levels
Instructions written at a parent level also apply to G44.5.
› From G44 Other headache syndromes
Broader instructions also apply from Chapter 6: Diseases of the nervous system.
Codes whose notes reference G44.5
- G44.1Excludes2
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about G44.5
Is G44.5 billable?
- No. G44.5 is a header code. Report one of its more specific subcodes instead.