Some doctors prescribe antihistamines to stop cluster headaches, but Diamond believes that histamine itself can stop the pain and has tried treating patients with histamine infusions.
Kelly swears by the histamine drip: "I don't mind putting in 12 days in the hospital if it will give me nine or 10 months headache-free," he says.
The newest research points to a structure deep in the brain, the hypothalamus, which is involved in pain perception, the body's cycles and pain perception. That may explain why different drugs used to treat clusters all work, despite their different actions.
But all the research matters a lot less to Skopek, who is pleased to at least be able to control, if not eliminate, his pain.
"I look forward to just growing up now with my family… my kids, my wife," Skopek says.