| G44039 | Episodic paroxysmal hemicrania, not intractable |
| G4404 | Chronic paroxysmal hemicrania |
| G44041 | Chronic paroxysmal hemicrania, intractable |
| G44049 | Chronic paroxysmal hemicrania, not intractable |
| G4405 | Short lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT) |
| G44051 | Short lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT), intractable |
| G44059 | Shrt lst unil nerlgif hdache w cnjnct inject/tear, not ntrct Short lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT), not intractable |
| G4409 | Other trigeminal autonomic cephalgias (TAC) |
| G44091 | Other trigeminal autonomic cephalgias (TAC), intractable |
| G44099 | Other trigeminal autonomic cephalgias (TAC), not intractable Other trigeminal autonomic cephalgias (TAC), not intractable |
| G441 | Vascular headache, not elsewhere classified |
| G442 | Tension-type headache |
| G4420 | Tension-type headache, unspecified |
| G44201 | Tension-type headache, unspecified, intractable |
| G44209 | Tension-type headache, unspecified, not intractable |
| G4421 | Episodic tension-type headache |
| G44211 | Episodic tension-type headache, intractable |
| G44219 | Episodic tension-type headache, not intractable |
| G4422 | Chronic tension-type headache |
| G44221 | Chronic tension-type headache, intractable |
| G44229 | Chronic tension-type headache, not intractable |
| G443 | Post-traumatic headache |
| G4430 | Post-traumatic headache, unspecified |
| G44301 | Post-traumatic headache, unspecified, intractable |
| G44309 | Post-traumatic headache, unspecified, not intractable |
| G4431 | Acute post-traumatic headache |
| G44311 | Acute post-traumatic headache, intractable |
| G44319 | Acute post-traumatic headache, not intractable |
| G4432 | Chronic post-traumatic headache |
| G44321 | Chronic post-traumatic headache, intractable |
| G44329 | Chronic post-traumatic headache, not intractable |
| G444 | Drug-induced headache, not elsewhere classified |
| G4440 | Drug-induced headache, not elsewhere classified, not intractable |
| G4441 | Drug-induced headache, not elsewhere classified, intractable Drug-induced headache, not elsewhere classified, intractable |
| G445 | Complicated headache syndromes |
| G4451 | Hemicrania continua |
| G4452 | New daily persistent headache (NDPH) |
| G4453 | Primary thunderclap headache |
| G4459 | Other complicated headache syndrome |
| G448 | Other specified headache syndromes |
| G4481 | Hypnic headache |
| G4482 | Headache associated with sexual activity |
| G4483 | Primary cough headache |
| G4484 | Primary exertional headache |
| G4485 | Primary stabbing headache |
| G4486 | Cervicogenic headache |
| G4489 | Other headache syndrome |
| G45 | Transient cerebral ischemic attacks and related syndromes |
| G450 | Vertebro-basilar artery syndrome |
| G451 | Carotid artery syndrome (hemispheric) |