A couple of interesting articles:
Strange List of Symptoms Perplexes Patients, Doctors
The latter puts to rest the belief that doctors always dismiss patients automatically as delusional without examining them:
Caroline Koblenzer, M.D. [...] a clinical professor of dermatology at the University of Pennsylvania and a psychoanalyst, has treated dozens of delusional parasitosis patients over the years and several dozen morgellons patients during the past six months.
“We do biopsies, we do blood tests, all those things that would rule out the extrusion of any foreign material, whether it be living or nonliving.
“If a patient came to me, I would make sure that he or she had an evaluation by a dermatologist to make sure that there wasn’t any.. .infestation by an organism,” Gerard Gallucci, M.D., said. ”
“I would recommend [doing] some testing to make sure that the patient does not have a skin infection,” said William Meehan, M.D., Ph.D., a University of Massachusetts psychiatry resident who co-wrote a paper about delusional parasitosis in the March Archives of Dermatology. “I would also want to rule out any other problem that might lead to a sensation of bugs crawling on the skin—for example.. .using cocaine or.. .certain endocrine problems, such as thyroid and liver disease.”