Why are doctors so quick to dismiss the possibility there might actually be something to morgellons?

Morgellens: The CDC states that the condition is not caused by an infection or anything in the environment. The CDC study also included a lab analysis of skin fibers in Morgellons patients. The analysis showed that these fibers were mostly cotton, such as typically found in clothing or bandages. CDC research also revealed that the skin sores seemed to be the result of long-term picking and scratching.