R51Headache

R51 is the ICD-10-CM diagnosis code for headache. It belongs to block R50-R69 (general symptoms and signs) and chapter 18 (symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified). It is a header code, so it can't be reported by itself; one of its 2 subcodes must be used instead.

To report this condition, pick the subcode that matches the documentation: R51.0 (with orthostatic component, not elsewhere classified) and R51.9 (unspecified).

The conditions in its Excludes2 note aren't part of R51, but may be coded alongside it if the patient has both: atypical face pain (G50.1), migraine and other headache syndromes (G43-G44) and trigeminal neuralgia (G50.0).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015, and changed in FY2021 (expanded into subcodes).

Before ICD-10, this condition was coded in ICD-9-CM as 784.0 (headache).