Symptoms and Signs of Cluster HeadacheCluster headaches begin as a severe, sudden headache, usually occurring 2 to 3 hours after falling asleep. An intense, sharp, burning and steady pain occurs on one side of the head and tends to get worse, reaching its peak within 10 minutes. Typical Cluster headaches are associated with the following symptoms- Burning sensation and discomfort in one side of face and head. Inflammation (redness and swelling) of the one eyeDrooping and swelling of the eyelids on the affected side. A smaller pupil during the attack Watering / Tears from the eye on the affected sideExcessive sweating of face and temples A blocked or runny nose (Rhinorrhea) on the affected side of the face Red, flushed face on the affected side Light sensitivity and intolerance to bright or flashy lights. References:Cluster headache - (http://www.nlm.nih.gov/medlineplus/ency/article/000786.htm)Cluster Headache FAQs - (http://www.emedicinehealth.com/cluster_headache_faqs/article_em.htm) Published on Feb 24, 2014