R51.9 Headache, unspecified
The ICD-10-CM code for Headache, unspecified is R51.9 (FY2026). It is a billable, claim-ready diagnosis code.
Classification
- Section
- R50-R69: General symptoms and signs (R50-R69)
- Category R51
- 3 codes (2 billable)
- FY2026 Status
- Stable since FY2024
Also Known As
ICD-10-CM Alphabetic Index entries that lead to R51.9:
- Headache
- Headache › chronic daily
- Headache › nasal septum
- Pain (s) › face, facial
- Headache › daily chronic
Inclusion Terms
- Facial pain NOS
U.S. Hospital Utilization
- An estimated 228,615 U.S. inpatient stays in 2023 included R51.9 among the documented diagnoses.
- 7,260 stays listed it as the principal diagnosis.
Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.
Official Coding Guidelines
Repeated falls vs history of fallingd. Repeated falls Code R29.6, Repeated falls, is for use for encounters when a patient has recently fallen and the reason for the fall is being investigated. Code Z91.81, History of falling, is for use when a patient has fallen in the past and is at risk for future falls. When appropriate, both codes R29.6 and Z91.81 may be assigned together.
Use of R40.20 unspecified coma; do not report for induced/sedatede. Coma Code R40.20, Unspecified coma, should be assigned when the underlying cause of the coma is not known, or the cause is a traumatic brain injury and the coma scale is not documented in the medical record. Do not report codes for unspecified coma, individual or total Glasgow coma scale scores for a patient with a medically induced coma or a sedated patient.
Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026