Congenital malformations, deformities, and chromosomal abnormalities (Q00-Q99).
- Craniocervical transition anomaly – anatomic variant at the junction of the brain and spinal cord.
Respiratory system (J00-J99)
- Chronic frontal sinusitis (sinusitis).
Eyes and eye appendages (H00-H59).
- Glaucoma attack – eye disease with seizure-like elevated intraocular pressure.
Endocrine, nutritional and metabolic diseases (E00-E90).
- Hypoglycemia (low blood sugar).
Skin and subcutaneous (L00-L99)
- Vasculitis (vascular inflammation) (here, for example, giant cell arteritis).
Cardiovascular system (I00-I99).
- Apoplexy (stroke)
- Arteriovenous malformations (AVM) – congenital malformation of blood vessels in which the arteries are directly connected to the veins; these occur mainly in the CNS and facial cranium.
- Chronic subdural hematoma (cSDH) – effusion of blood between the dura mater (outermost meninges) and the leptomeninges (soft meninges).
- Hypertension (high blood pressure)
- Sinus vein thrombosis (SVT) – occlusion of a cerebral sinus (large venous blood vessels of the brain arising from duraduplications) by a thrombus (blood clot); clinical presentation: headache, congestive papules, and epileptic seizures.
Musculoskeletal system and connective tissue (M00-M99).
- Arteritis temporalis (synonyms: Arteriitis cranialis; Horton’s disease; giant cell arteritis; Horton-Magath-Brown syndrome) – systemic vasculitis (vascular inflammation) affecting the arteriae temporales (temporal arteries), especially in the elderly.
- Myoarthropathy (MAP) of the masticatory muscles / painful disease of the masticatory muscles and / or temporomandibular joints, craniomandibular dysfunction (CMD).
Neoplasms – tumor diseases (C00-D48).
- Brain tumors, unspecified
- Nasal cavity tumors
- Paranasal sinus tumors
Psyche – nervous system (F00-F99; G00-G99)
- Chronic meningitis (meningitis).
- Chronic migraineNote: If the headache is frequent or chronic, it must be differentiated from migraine.
- Chronic paroxysmal hemicrania – Headache that has no symptom-free intervals.
- Chronic hemiparesis headache
- Encephalitis (inflammation of the brain)
- Meningitis (meningitis)
- Pseudotumor cerebri (idiopathic intracranial hypertension) – increase in pressure inside the skull (intracranial hypertension) without the presence of other causative space-occupying processes (i.e., tumors, hemorrhages, etc.).
- Sleep apnea syndrome – sleep disorder with breathing pauses during sleep and daytime sleepiness.
- SUNCT syndrome (shortlasting unilateral neuralgiform headache attacks with conjunctival injection, tearing, sweating and rhinorrhea). – Headache with shorter attacks and higher frequency than cluster headache.
- Trigeminal neuralgia – usually unexplained severe pain in the face due to irritation of a facial nerve.
Injuries, poisonings and other consequences of external causes (S00-T98).
- Trauma (injury), unspecified
Other
- Oromandibular dysfunction – mainly due to grinding of teeth at night.
Medication
- Analgesics (painkillers) such as ASA (acetylsalicylic acid) [drug-induced headache, MIKS].
- Ergot alkaloids – drugs such as ergotamine.
- Triptans (serotonin agonists) – drugs such as sumatriptan, which are used to treat migraines
