The following is a differential diagnosis for unilateral headaches with typical associated features:

• Migraine headache ->  throbbing pain preceded by aura; nausea; photophobia; chronicity.
• Cluster headache ->  piercing eye pain; ipsilateral lacrimation and rhinorrhea; group of headaches come periodically in waves.
• Temporal arteritis ->  dull ache over temporal artery; associated with arthralgia, myalgia, and anemia; typically in older populations.
• Glaucoma ->  eye pain with cloudy appearing cornea; eyeball feels hard; pupillary dilitation may worsen pain.
• Sinusitis ->  associated with sinus congestion; tenderness over sinus with or without swelling; typically only relieved with decongestants and/or antibiotics.
• Subarachnoid hemorrhage ->  pain may be diffuse or unilateral; sudden onset of severe pain; may be associated with a stiff neck.