When should i go to the emergency room for a headache?

Seldom: The er is critical if there is consideration for hospitalization, surgery, or a life-threatening problem. Although severe headaches may require an injection to control, the er is very expensive, and many insurance plans have limited coverage. Perhaps best to have medication to stop the headache, or even take a medicine to prevent the headache. The er should be a last resort if all else fails.

Rarely: The er is one of the worst places to be with a severe migraine. It is bright, noisy, too much activity, and increases anxiety. Migraines need dark, quiet and sleep. Acute new headache with loss of function may indicate a stroke. This needs er care. Chronic headache needs routine clinic evaluation - not er.