Cluster headaches are defined as a group of at least five headache attacks causing unilateral orbital, supraorbital and/or temporal pain, with at least one of the following simultaneous associated findings on the affected side:
conjunctival injection
lacrimation
nasal congestion
rhinorrhea
ptosis
miosis
sweating on the forehead
Cluster headaches can occur at a frequency of one every other day t eight episodes per day.
