Morgellons () is the informal name of a self-diagnosed, scientifically unsubstantiated skin condition in which individuals have sores that they believe contain fibrous material. Morgellons is not well understood, but the general medical consensus is that it is a form of delusional parasitosis, on the psychiatric spectrum. The sores are typically the result of compulsive scratching, and the fibers, when analysed, are consistently found to have originated from cotton and other textiles.
The condition was named in 2002 by Mary Leitao, a mother who rejected the medical diagnosis of her son's delusional parasitosis. She chose the name from a letter written by a mid-17th-century physician. Leitao and others involved in her Morgellons Research Foundation successfully lobbied members of the U.S. Congress and the U.S. Centers for Disease Control and Prevention (CDC) to investigate the condition in 2006. CDC researchers issued the results of their multi-year study in January 2012, indicating that no disease organisms were present in the samples from the individuals examined and that the fibers found were likely cotton. The researchers concluded that the condition was "similar to more commonly recognized conditions such as delusional infestation".