| Infection |
| Bacterial meningitis* |
| Viral encephalitis* |
| Orbital or cerebral abscess* |
| Viral infection, including viral meningitis¶ |
| Lyme meningitis |
| Streptococcal pharyngitis¶ |
| Otitis media¶ |
| Sinusitis¶ |
| Dental infection¶ |
| Increased intracranial pressure |
| Tumor* |
| Hydrocephalus* |
| Intracranial hemorrhage* |
| Idiopathic intracranial hypertension |
| Other conditions |
| Carbon monoxide poisoning* |
| Hypertensive encephalopathy* |
| Temporomandibular joint dysfunction |
| Cluster headache |
| Primary headache |
| Migraine¶ |
| Tension-type headache¶ |
| Chronic daily headache |
