Porphyria is a rare and intensely painful blood disease. Because it can manifest itself with symptoms similar to those caused by far more common disorders, it can be difficult to diagnose. Colin McEwen went through an 18-year diagnostic odyssey, in part because injuries he suffered as a child from an auto accident obscured from doctors the actual cause of his maladies. His problems were made that much more difficult as his search for relief from the pain from his disease led doctors to dismiss him as a drug-seeker. We spoke to McEwen about porphyria, the experiences he went through to get to a diagnosis, and how having a diagnosis has changed his ability to manage the disease.