What is a cancer cluster? A cancer cluster is defined by the Centers for Disease Control as a greater-than-expected number of cancer cases that occurs within a group of people in a geographic area ...

There's no single definition of seizure clusters, also called cluster seizures. In general, it's a group of seizures that happen more often than you're used to within a certain span of time. Some ...

Cluster headaches cause severe pain around the eye, usually on one side of the head. The pain can feel like stabbing, sharp, or burning rather than throbbing. They can last from 15 minutes to several ...