Index to Diseases entry: Headache
Each row is a subterm under the entry. Indented rows refine the row above; “see” sends you to another entry. Look the code up in the tabular list before reporting it: the tabular notes can require a more specific or an additional code.
| Documentation | Code | Code description or cross-reference |
|---|---|---|
| with | — | |
| orthostatic component NEC | R51.0 | Headache with orthostatic component, not elsewhere classified |
| positional component NEC | R51.0 | Headache with orthostatic component, not elsewhere classified |
| allergic NEC | G44.89 | Other headache syndrome |
| associated with sexual activity | G44.82 | Headache associated with sexual activity |
| cervicogenic | G44.86 | Cervicogenic headache |
| chronic daily | R51.9 | Headache, unspecified |
| cluster | G44.009 | Cluster headache syndrome, unspecified, not intractable |
| chronic | G44.029 | Chronic cluster headache, not intractable |
| episodic | G44.019 | Episodic cluster headache, not intractable |
| intractable | G44.001 | Cluster headache syndrome, unspecified, intractable |
| not intractable | G44.009 | Cluster headache syndrome, unspecified, not intractable |
| cough(primary) | G44.83 | Primary cough headache |
| daily chronic | R51.9 | Headache, unspecified |
| drug-induced NEC | G44.40 | Drug-induced headache, not elsewhere classified, not intractable |
| intractable | G44.41 | Drug-induced headache, not elsewhere classified, intractable |
| not intractable | G44.40 | Drug-induced headache, not elsewhere classified, not intractable |
| exertional(primary) | G44.84 | Primary exertional headache |
| histamine | G44.009 | Cluster headache syndrome, unspecified, not intractable |
| intractable | G44.001 | Cluster headache syndrome, unspecified, intractable |
| not intractable | G44.009 | Cluster headache syndrome, unspecified, not intractable |
| hypnic | G44.81 | Hypnic headache |
| lumbar puncture | G97.1 | Other reaction to spinal and lumbar puncture |
| medication overuse | G44.40 | Drug-induced headache, not elsewhere classified, not intractable |
| intractable | G44.41 | Drug-induced headache, not elsewhere classified, intractable |
| not intractable | G44.40 | Drug-induced headache, not elsewhere classified, not intractable |
| menstrual | — | see Migraine, menstrual |
| migraine(type) | G43.909 | Migraine, unspecified, not intractable, without status migrainosus |
| nasal septum | R51.9 | Headache, unspecified |
| neuralgiform, short lasting unilateral, with conjunctival injection and tearing(SUNCT) | G44.059 | Short lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT), not intractable |
| intractable | G44.051 | Short lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT), intractable |
| not intractable | G44.059 | Short lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT), not intractable |
| new daily persistent(NDPH) | G44.52 | New daily persistent headache (NDPH) |
| orgasmic | G44.82 | Headache associated with sexual activity |
| periodic syndromes in adults and children | G43.C0 | Periodic headache syndromes in child or adult, not intractable |
| with refractory migraine | G43.C1 | Periodic headache syndromes in child or adult, intractable |
| intractable | G43.C1 | Periodic headache syndromes in child or adult, intractable |
| not intractable | G43.C0 | Periodic headache syndromes in child or adult, not intractable |
| without refractory migraine | G43.C0 | Periodic headache syndromes in child or adult, not intractable |
| postspinal puncture | G97.1 | Other reaction to spinal and lumbar puncture |
| post-traumatic | G44.309 | Post-traumatic headache, unspecified, not intractable |
| acute | G44.319 | Acute post-traumatic headache, not intractable |
| chronic | G44.329 | Chronic post-traumatic headache, not intractable |
| intractable | G44.301 | Post-traumatic headache, unspecified, intractable |
| not intractable | G44.309 | Post-traumatic headache, unspecified, not intractable |
| pre-menstrual | — | see Migraine, menstrual |
| preorgasmic | G44.82 | Headache associated with sexual activity |
| primary | — | |
| cough | G44.83 | Primary cough headache |
| exertional | G44.84 | Primary exertional headache |
| stabbing | G44.85 | Primary stabbing headache |
| thunderclap | G44.53 | Primary thunderclap headache |
| rebound | G44.40 | Drug-induced headache, not elsewhere classified, not intractable |
| intractable | G44.41 | Drug-induced headache, not elsewhere classified, intractable |
| not intractable | G44.40 | Drug-induced headache, not elsewhere classified, not intractable |
| short lasting unilateral neuralgiform, with conjunctival injection and tearing(SUNCT) | G44.059 | Short lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT), not intractable |
| intractable | G44.051 | Short lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT), intractable |
| not intractable | G44.059 | Short lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT), not intractable |
| specified syndrome NEC | G44.89 | Other headache syndrome |
| spinal and epidural anesthesia - induced | T88.59 | Other complications of anesthesia |
| in labor and delivery | O74.5 | Spinal and epidural anesthesia-induced headache during labor and delivery |
| in pregnancy | O29.4- | Spinal and epidural anesthesia induced headache during pregnancy |
| postpartum, puerperal | O89.4 | Spinal and epidural anesthesia-induced headache during the puerperium |
| spinal fluid loss(from puncture) | G97.1 | Other reaction to spinal and lumbar puncture |
| stabbing(primary) | G44.85 | Primary stabbing headache |
| tension(-type) | G44.209 | Tension-type headache, unspecified, not intractable |
| chronic | G44.229 | Chronic tension-type headache, not intractable |
| episodic | G44.219 | Episodic tension-type headache, not intractable |
| intractable | G44.201 | Tension-type headache, unspecified, intractable |
| not intractable | G44.209 | Tension-type headache, unspecified, not intractable |
| thunderclap(primary) | G44.53 | Primary thunderclap headache |
| vascular NEC | G44.1 | Vascular headache, not elsewhere classified |
Tabular list notes for R51.9
- Inclusion terms
- Facial pain NOS
How to read an Index to Diseases entry
- Words in parentheses after a term are nonessential modifiers: they may or may not appear in the record, and they do not change the code.
- Indented subterms are essential modifiers. Each one describes a different site, type or cause, and when the record supports it, the subterm's code replaces the default code.
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- A code that ends in a dash, such as I50.-, is incomplete: the tabular list gives the characters it still needs.
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Frequently asked questions
What is the ICD-10 code for headache?
R51.9 (Headache, unspecified) is the code the index assigns to "Headache" with no further detail. Confirm it in the tabular list before reporting it, because the tabular notes can require a different or additional code.
Which documentation changes the code for headache?
The index lists 65 subterms with their own codes, including with orthostatic component NEC (R51.0); with positional component NEC (R51.0); allergic NEC (G44.89); associated with sexual activity (G44.82); cervicogenic (G44.86).
Sources
Every figure on this page is taken from the CMS publications below, as released by the Centers for Medicare & Medicaid Services. Projection built 2026-10-10. Verify against the primary file before billing or contracting decisions. The reference methodology explains how each figure is computed from these files.
- ICD-10-CM FY2027 tabular order file (category titles)Version FY2027 · effective 2026-10-01 · file icd10cm_order_2027.txtSHA-256 38981fb2c1226e2b…
- ICD-10-CM FY2027 tabular list (chapter titles and ranges)Version FY2027 · effective 2026-10-01 · file 2027-code-tables-tabular-index.zipSHA-256 37baa476323714be…
- ICD-10-CM FY2027 code descriptions addenda (codes added, deleted and revised)Version FY2027 · effective 2026-10-01 · file icd10cm_codes_addenda_2027.txtSHA-256 cfba025073235af4…
Disclaimer
The entry, subterms and codes are reproduced from the FY2027 ICD-10-CM index; code descriptions are from the FY2027 code files. Code from the medical record using both the index and the tabular list, under the ICD-10-CM Official Guidelines. Not legal, clinical or billing advice.
Found a figure that does not match the CMS file? Report a data correction with the CMS file and the value you expected; the request reaches the editorial team through the contact form.