2026 ICD-10-CM Diagnosis Code R51Headache
ICD-10-CM Codes›R00–R99›R50-R69›R51
- Non-Billable Category
- Not Chronic
R51 is a non-billable ICD-10-CM category code for headache, so it cannot be submitted on claims. Use a more specific code from this category instead, such as R51.0 and R51.9. As a symptom code, it should not be used as a principal diagnosis once a related definitive diagnosis has been established. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Headache; including migraine and Nervous system signs and symptoms.
This medical diagnosis code is frequently used in Family Practice, Internal Medicine, and Pediatrics medical specialties to designate conditions such headache.
Code Identity
Code Classification
Specific Coding for HeadacheOverview
Tabular List NotesGuidance
Coding notes and annotation back-references applicable to this code.
Type 2 Excludes
A type 2 excludes note represents "Not included here". An excludes2 note indicates that the condition excluded is not part of the condition represented by the code, but a patient may have both conditions at the same time. When an Excludes2 note appears under a code, it is acceptable to use both the code and the excluded code together, when appropriate.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Cluster Headache
a primary headache disorder that is characterized by severe, strictly unilateral pain which is orbital, supraorbital, temporal or in any combination of these sites, lasting 15-180 min. occurring 1 to 8 times a day. the attacks are associated with one or more of the following, all of which are ipsilateral: conjunctival injection, lacrimation, nasal congestion, rhinorrhea, facial sweating, eyelid edema, and miosis. (international classification of headache disorders, 2nd ed. cephalalgia 2004: suppl 1)Headache
the symptom of pain in the cranial region. it may be an isolated benign occurrence or manifestation of a wide variety of headache disorders.Headache Disorders
various conditions with the symptom of headache. headache disorders are classified into major groups, such as primary headache disorders (based on characteristics of their headache symptoms) and secondary headache disorders (based on their etiologies). (international classification of headache disorders, 2nd ed. cephalalgia 2004: suppl 1)Headache Disorders, Primary
conditions in which the primary symptom is headache and the headache cannot be attributed to any known causes.Headache Disorders, Secondary
conditions with headache symptom that can be attributed to a variety of causes including brain vascular disorders; wounds and injuries; infection; drug use or its withdrawal.Migraine Disorders
a class of disabling primary headache disorders, characterized by recurrent unilateral pulsatile headaches. the two major subtypes are common migraine (without aura) and classic migraine (with aura or neurological symptoms). (international classification of headache disorders, 2nd ed. cephalalgia 2004: suppl 1)Post-Dural Puncture Headache
a secondary headache disorder attributed to low cerebrospinal fluid pressure caused by spinal puncture, usually after dural or lumbar puncture.Post-Traumatic Headache
secondary headache attributed to trauma of the head and/or the neck.Tension-Type Headache
a common primary headache disorder, characterized by a dull, non-pulsatile, diffuse, band-like (or vice-like) pain of mild to moderate intensity in the head; scalp; or neck. the subtypes are classified by frequency and severity of symptoms. there is no clear cause even though it has been associated with muscle contraction and stress. (international classification of headache disorders, 2nd ed. cephalalgia 2004: suppl 1)Vascular Headaches
secondary headache disorders attributed to a variety of cranial or cervical vascular disorders, such as brain ischemia; intracranial hemorrhages; and central nervous system vascular malformations.
Patient EducationClinical
Headache
Almost everyone has had a headache. Headache is the most common form of pain. It's a major reason people miss days at work or school or visit the doctor.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert R51 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About R51Overview
Is R51 (Headache) a billable code?
No. This is a category header that groups the codes for headache, and headers cannot be submitted on claims. Claims for headache need a more specific code from this category, such as R51.0 and R51.9.
Can R51 be a principal diagnosis?
Use it with care. This is a symptom code, so once a definitive diagnosis explaining the headache is established, that condition takes the principal position instead.
What is the ICD-9 equivalent of R51?
Under the General Equivalence Mappings, headache converts to ICD-9-CM 784.0 (headache). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.
