Cluster Headaches are a series of relatively short but extremely painful headaches every day for weeks or months at a time.
This is migraine variant, 10-50 times less common than migraine. There is severe unilateral periorbital pain, unilateral lacrimation and nasal congestion.
Infrequently, pain may extend into the ear, neck, or shoulder. Although watering of the eye is frequently identified, some patients may only experience some redness of the conjunctiva.
Eyelid drooping or swelling and a runny nose (rhinorrhea) are often associated with the pain of a cluster headache.
The pain is almost always one-sided, and it stays on the same side during a period.