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.
