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R51.9 — Headache, unspecified
R51.9
What this code means
Headache recorded as a symptom when a specific headache type has not been coded.
Also called: headache, cephalalgia.
When this code is used
Used for headache, unspecified.
Where it sits in ICD-10-CM
Code R51.9 belongs to Chapter 18: Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified, which covers codes R00–R99 in the FY2027 ICD-10-CM tabular list. The official description above is copied verbatim from the CDC/NCHS FY2027 code file.
Related symptoms
Related anatomy
Watch: related videos
Frequently asked questions
What is ICD-10-CM code R51.9?
R51.9 is the ICD-10-CM diagnosis code for “Headache, unspecified”. Headache recorded as a symptom when a specific headache type has not been coded.
When is code R51.9 used?
Used for headache, unspecified. It belongs to Chapter 18 of ICD-10-CM (Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified).
This guide explains ICD-10-CM codes in plain language for patients, students and other readers. It is educational information only — not coding, billing or medical advice. The code recorded for any real encounter is assigned from the full clinical documentation by the treating team and qualified coders, and only they can decide which code fits a specific case.