Version 2024
No Valid Principal Dx

2024 ICD-10-CM Diagnosis Code R51.9

Headache, unspecified

ICD-10-CM Code:
Short Description:
Headache, unspecified
Is Billable?
Yes - Valid for Submission
Chronic Condition Indicator: [1]
Not chronic
Code Navigator:

Code Classification

  • Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
    • General symptoms and signs
      • Headache

R51.9 is a billable diagnosis code used to specify a medical diagnosis of headache, unspecified. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2023 through September 30, 2024.

Unspecified diagnosis codes like R51.9 are acceptable when clinical information is unknown or not available about a particular condition. Although a more specific code is preferable, unspecified codes should be used when such codes most accurately reflect what is known about a patient's condition. Specific diagnosis codes should not be used if not supported by the patient's medical record.

According to ICD-10-CM guidelines this code should not to be used as a principal diagnosis code when a related definitive diagnosis has been established.

Approximate Synonyms

The following clinical terms are approximate synonyms or lay terms that might be used to identify the correct diagnosis code:

  • Aching headache
  • Acute headache
  • Acute pain in face
  • Aural headache
  • Bilateral headache
  • Chronic daily headache
  • Chronic orofacial pain
  • Chronic pain in face
  • Chronic pain in face
  • Chronic pain in face
  • Chronic primary orofacial pain
  • Chronic secondary facial pain
  • Craniofacial pain
  • Daily headache
  • Delayed headache caused by alcohol
  • Dental headache
  • Effects of high altitude
  • Facial tenderness
  • Frequent headache
  • Frontal headache
  • Frontal sinus pain
  • Generalized headache
  • Headache
  • Headache caused by carbon monoxide
  • Headache character - finding
  • Headache character - finding
  • Headache character - finding
  • Headache disorder
  • Headache due to acute angle closure glaucoma
  • Headache due to arterial hypertension
  • Headache due to cold exposure
  • Headache due to external compression of head
  • Headache due to high altitude
  • Headache due to intracranial disease
  • Headache due to intracranial neoplasm
  • Headache due to reversible cerebral vasoconstriction syndrome
  • Headache following myelography
  • Heavy head
  • Hindbrain hernia headache
  • Intermittent headache
  • Low pressure headache
  • Low pressure headache
  • Low pressure headache
  • Maxillary sinus pain
  • Morning headache
  • Muscular headache
  • Nasal headache
  • Obstetric spinal and epidural anesthesia-induced headache
  • Occipital headache
  • Pain due to neoplastic disease
  • Pain in cheek
  • Pain in chin
  • Pain in face
  • Pain of head and neck region
  • Pain radiating to head
  • Parietal headache
  • Post dural puncture headache
  • Post dural puncture headache
  • Post-ictal state
  • Postpartum headache
  • Postseizure headache
  • Referred pain
  • Referred pain in face
  • Scalp tenderness
  • Shooting headache
  • Shooting pain
  • Sinus headache
  • Temporal headache
  • Tenderness of head and neck region
  • Tenderness of neck
  • Tenderness of respiratory structure
  • Tenderness of respiratory structure
  • Tenderness over frontal sinus
  • Tenderness over maxillary sinus
  • Throbbing headache
  • Throbbing pain
  • Unilateral headache
  • Unilateral left sided headache
  • Unilateral right sided headache
  • Viral headache

Clinical Classification

Clinical CategoryCCSR Category CodeInpatient Default CCSROutpatient Default CCSR
Headache; including migraineNVS010Y - Yes, default inpatient assignment for principal diagnosis or first-listed diagnosis.Y - Yes, default outpatient assignment for principal diagnosis or first-listed diagnosis.
Nervous system signs and symptomsSYM010N - Not default inpatient assignment for principal diagnosis or first-listed diagnosis.N - Not default outpatient assignment for principal diagnosis or first-listed diagnosis.

Clinical Information

  • 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.
  • SF-MPQ-2 - Shooting Pain|SFMP2-Shooting Pain|SFMP2-Shooting Pain|SFMP202

    short-form mcgill pain questionnaire-2 (short form mpq) shooting pain.
  • Shooting Pain

    an intense sensation of discomfort or distress that radiates from one location to another sharply.

Tabular List of Diseases and Injuries

The following annotation back-references are applicable to this diagnosis code. The Tabular List of Diseases and Injuries is a list of ICD-10-CM codes, organized "head to toe" into chapters and sections with coding notes and guidance for inclusions, exclusions, descriptions and more.

Inclusion Terms

Inclusion Terms
These terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
  • Facial pain NOS

Index to Diseases and Injuries References

The following annotation back-references for this diagnosis code are found in the injuries and diseases index. The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10-CM code(s).

Replacement Code

R519 replaces the following previously assigned ICD-10-CM code(s):

  • R51 - Headache

Patient Education


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.

The most common type of headache is a tension headache. Tension headaches are due to tight muscles in your shoulders, neck, scalp and jaw. They are often related to stress, depression or anxiety. You are more likely to get tension headaches if you work too much, don't get enough sleep, miss meals, or use alcohol.

Other common types of headaches include migraines, cluster headaches, and sinus headaches. Most people can feel much better by making lifestyle changes, learning ways to relax and taking pain relievers.

Not all headaches require a doctor's attention. But sometimes headaches warn of a more serious disorder. Let your health care provider know if you have sudden, severe headaches. Get medical help right away if you have a headache after a blow to your head, or if you have a headache along with a stiff neck, fever, confusion, loss of consciousness, or pain in the eye or ear.

NIH: National Institute of Neurological Disorders and Stroke

[Learn More in MedlinePlus]

Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - Code Added, effective from 10/1/2020 through 9/30/2021


[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.