Cluster Headache from phenotype deprecated-Acute Severe Headache true https://meshb.nlm.nih.gov/record/ui?ui=D003027 MESH:D003027 A primary headache disorder that is characterized by severe, strictly unilateral PAIN which is orbital, supraorbital, temporal or in any combination of these sites, lasting 15-180 min. occurring 1 to 8 times a day. The attacks are associated with one or more of the following, all of which are ipsilateral: conjunctival injection, lacrimation, nasal congestion, rhinorrhea, facial SWEATING, eyelid EDEMA, and miosis. Ask a clinician if this is different to a cluster headache?