ICD-10-CM Codes
R00-R99
R50-R69
R51-
2023 ICD-10-CM Diagnosis Code R51.9

2023 ICD-10-CM Diagnosis Code R51.9

Headache, unspecified

2021 - New Code

2022

2023

Billable/Specific Code

R51.9 is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
The 2023 edition of ICD-10-CM R51.9 became effective on October 1, 2022.
This is the American ICD-10-CM version of R51.9 - other international versions of ICD-10 R51.9 may differ.

Applicable To

Facial pain NOS

The following code(s) above R51.9 contain annotation back-references

Annotation Back-References

In this context, annotation back-references refer to codes that contain:

Applicable To annotations, or
Code Also annotations, or
Code First annotations, or
Excludes1 annotations, or
Excludes2 annotations, or
Includes annotations, or
Note annotations, or
Use Additional annotations

that may be applicable to R51.9:

R00-R99
2023 ICD-10-CM Range R00-R99
Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
Note
- This chapter includes symptoms, signs, abnormal results of clinical or other investigative procedures, and ill-defined conditions regarding which no diagnosis classifiable elsewhere is recorded.
- Signs and symptoms that point rather definitely to a given diagnosis have been assigned to a category in other chapters of the classification. In general, categories in this chapter include the less well-defined conditions and symptoms that, without the necessary study of the case to establish a final diagnosis, point perhaps equally to two or more diseases or to two or more systems of the body. Practically all categories in the chapter could be designated 'not otherwise specified', 'unknown etiology' or 'transient'. The Alphabetical Index should be consulted to determine which symptoms and signs are to be allocated here and which to other chapters. The residual subcategories, numbered .8, are generally provided for other relevant symptoms that cannot be allocated elsewhere in the classification.
- The conditions and signs or symptoms included in categories R00-R94 consist of:
- (a) cases for which no more specific diagnosis can be made even after all the facts bearing on the case have been investigated;
- (b) signs or symptoms existing at the time of initial encounter that proved to be transient and whose causes could not be determined;
- (c) provisional diagnosis in a patient who failed to return for further investigation or care;
- (d) cases referred elsewhere for investigation or treatment before the diagnosis was made;
- (e) cases in which a more precise diagnosis was not available for any other reason;
- (f) certain symptoms, for which supplementary information is provided, that represent important problems in medical care in their own right.
Type 2 Excludes
- abnormal findings on antenatal screening of mother (O28.-)
- certain conditions originating in the perinatal period (P04-P96)
- signs and symptoms classified in the body system chapters
- signs and symptoms of breast (N63, N64.5)
Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified
R51
ICD-10-CM Diagnosis Code R51
Headache
Type 2 Excludes
- atypical face pain (G50.1)
- migraine and other headache syndromes (G43-G44)
- trigeminal neuralgia (G50.0)
Headache

ICD-10-CM R51.9 is grouped within Diagnostic Related Group(s) (MS-DRG v40.0):

102 Headaches with mcc
103 Headaches without mcc

Code History

2021 (effective 10/1/2020): New code
2022 (effective 10/1/2021): No change
2023 (effective 10/1/2022): No change

Code annotations containing back-references to R51.9:

Type 1 Excludes: R52
, G43
, G44

ICD-10-CM Diagnosis Code R52
Pain, unspecified
Applicable To
- Acute pain NOS
- Generalized pain NOS
- Pain NOS
Type 1 Excludes
- acute and chronic pain, not elsewhere classified (G89.-)
- localized pain, unspecified type - code to pain by site, such as:
- abdomen pain (R10.-)
- back pain (M54.9)
- breast pain (N64.4)
- chest pain (R07.1-R07.9)
- ear pain (H92.0-)
- eye pain (H57.1)
- headache (R51.9)
- joint pain (M25.5-)
- limb pain (M79.6-)
- lumbar region pain (M54.5-)
- pelvic and perineal pain (R10.2)
- shoulder pain (M25.51-)
- spine pain (M54.-)
- throat pain (R07.0)
- tongue pain (K14.6)
- tooth pain (K08.8)
- renal colic (N23)
- pain disorders exclusively related to psychological factors (F45.41)
ICD-10-CM Diagnosis Code G43
Migraine
Note
- the following terms are to be considered equivalent to intractable: pharmacoresistant (pharmacologically resistant), treatment resistant, refractory (medically) and poorly controlled
Type 1 Excludes
- headache NOS (R51.9)
- lower half migraine (G44.00)
Type 2 Excludes
- headache syndromes (G44.-)
Use Additional
- code for adverse effect, if applicable, to identify drug (T36-T50 with fifth or sixth character 5)
ICD-10-CM Diagnosis Code G44
Other headache syndromes
Type 1 Excludes
- headache NOS (R51.9)
Type 2 Excludes
- atypical facial pain (G50.1)
- headache due to lumbar puncture (G97.1)
- migraines (G43.-)
- trigeminal neuralgia (G50.0)
Type 2 Excludes: G89

ICD-10-CM Diagnosis Code G89
Pain, not elsewhere classified
Code Also
- related psychological factors associated with pain (F45.42)
Type 1 Excludes
- generalized pain NOS (R52)
- pain disorders exclusively related to psychological factors (F45.41)
- pain NOS (R52)
Type 2 Excludes
- atypical face pain (G50.1)
- headache syndromes (G44.-)
- localized pain, unspecified type - code to pain by site, such as:
- abdomen pain (R10.-)
- back pain (M54.9)
- breast pain (N64.4)
- chest pain (R07.1-R07.9)
- ear pain (H92.0-)
- eye pain (H57.1)
- headache (R51.9)
- joint pain (M25.5-)
- limb pain (M79.6-)
- lumbar region pain (M54.5-)
- painful urination (R30.9)
- pelvic and perineal pain (R10.2)
- shoulder pain (M25.51-)
- spine pain (M54.-)
- throat pain (R07.0)
- tongue pain (K14.6)
- tooth pain (K08.8)
- renal colic (N23)
- migraines (G43.-)
- myalgia (M79.1-)
- pain from prosthetic devices, implants, and grafts (T82.84, T83.84, T84.84, T85.84-)
- phantom limb syndrome with pain (G54.6)
- vulvar vestibulitis (N94.810)
- vulvodynia (N94.81-)

Diagnosis Index entries containing back-references to R51.9:

Headache R51.9
- chronic daily R51.9
- daily chronic R51.9
- nasal septum R51.9
Pain(s) R52
- see also Painful
ICD-10-CM Diagnosis Code R52
Pain, unspecified
Applicable To
Acute pain NOS
Generalized pain NOS
Pain NOS
Type 1 Excludes
acute and chronic pain, not elsewhere classified (G89.-)
localized pain, unspecified type - code to pain by site, such as:
abdomen pain (R10.-)
back pain (M54.9)
breast pain (N64.4)
chest pain (R07.1-R07.9)
ear pain (H92.0-)
eye pain (H57.1)
headache (R51.9)
joint pain (M25.5-)
limb pain (M79.6-)
lumbar region pain (M54.5-)
pelvic and perineal pain (R10.2)
shoulder pain (M25.51-)
spine pain (M54.-)
throat pain (R07.0)
tongue pain (K14.6)
tooth pain (K08.8)
renal colic (N23)
pain disorders exclusively related to psychological factors (F45.41)
- face, facial R51.9

ICD-10-CM Codes Adjacent To R51.9

R50 Fever of other and unknown origin

R50.2 Drug induced fever

R50.8 Other specified fever

R50.81 Fever presenting with conditions classified elsewhere

R50.82 Postprocedural fever

R50.83 Postvaccination fever

R50.84 Febrile nonhemolytic transfusion reaction

R50.9 Fever, unspecified

R51 Headache

R51.0 Headache with orthostatic component, not elsewhere classified

R51.9 Headache, unspecified

R52 Pain, unspecified

R53 Malaise and fatigue

R53.0 Neoplastic (malignant) related fatigue

R53.1 Weakness

R53.2 Functional quadriplegia

R53.8 Other malaise and fatigue

R53.81 Other malaise

R53.82 Chronic fatigue, unspecified

R53.83 Other fatigue

R54 Age-related physical debility

Reimbursement claims with a date of service on or after October 1, 2015 require the use of ICD-10-CM codes.

2023 ICD-10-CM Diagnosis Code R51.9

Headache, unspecified

Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified

Headache

Pain, unspecified

Migraine

Other headache syndromes

Pain, not elsewhere classified

Pain, unspecified