For a small segment of the population, cluster headaches can be a debilitating condition that strikes without warning. Cluster headaches attack at seemingly random intervals, for which the name “cluster” is given. Patients can go years without a single cluster headache, and suddenly suffer them for days or weeks at a time. The exact cause of cluster headaches is not known, although it is thought that stress, alcohol, and drugs are all prompters of the condition. Even without these factors, however, a series of cluster headaches can befall a patient at any time in their life. A cluster headache can be easily identified by the pain level.