ICD-10 R51.9: Headache, unspecified
Headache as chief complaint without etiologic diagnosis. Should specify (G43 migraine, G44.x other) when classified.
Clinical context
Headache as chief complaint without etiologic diagnosis. Should specify (G43 migraine, G44.x other) when classified.
Documentation requirements
- Headache pattern, triggers, duration
- Red-flag symptom screen
- Validated tool (HIT-6, MIDAS) if relevant
Common related procedures
- 99214 E&M
- 70551 MRI brain (requires PA)
- 70450 CT head
Common payer denial patterns
- MRI brain denied with R51.9 alone — need red flags or specific etiology suspicion
- Botox / CGRP injection requires G43 migraine + frequency criteria
Frequently asked questions
What does ICD-10 R51.9 mean?
Headache, unspecified
When is this code documented?
Headache as chief complaint without etiologic diagnosis. Should specify (G43 migraine, G44.x other) when classified.
What documentation supports this code?
Headache pattern, triggers, duration; Red-flag symptom screen; Validated tool (HIT-6, MIDAS) if relevant.
What are common denials associated with this diagnosis?
MRI brain denied with R51.9 alone — need red flags or specific etiology suspicion; Botox / CGRP injection requires G43 migraine + frequency criteria.
Related diagnoses
Sources
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