The following extract is from an article that deals with several delusional disorders. The article differentiates Morgellons from delusions of parasitosis. Note that this article does not mean the symptoms of Morgellons are purely delusional, but rather that, as with DOP, there is often a delusional component to what may or may not be a physical condition. I’ve added it here as it is a useful reference to the most current medical opinion on Morgellons. I’d encourage people to read the full article, available via this link.
Delusional disorders in dermatology: a brief review
David T Robles MD PhD1, Sharon Romm MD2, Heidi Combs MD2, Jonathan Olson BS1, Phil Kirby MD1
Dermatology Online Journal (2008 June 15) 14 (6): 2
In the seventeenth century Sir Thomas Browne used the term Morgellons disease to describe an unusual symptom complex resembling those seen in patients today . Patients with this condition maintain the unshakeable belief that fibers or some other material is imbedded or emerging from their skin. They pick and dig at their skin to extract the offending “material.” They may reject the notion that they have parasites but may still exhibit the “matchbox” sign, bringing in fragments of clothing fibers, lint, hair fibers and dried skin fragments for examination.
We consider Morgellons to be within the spectrum of delusions of parasitosis, except that the patients are focused not on parasites but on “unusual material” that they believe is in their skin. We have seen a number of such patients in our clinic and all manipulate their lesions enough to self-induce irregular ulcerations. They frequently dig at their lesions with their own nails as well as house-hold items such as nail clippers or tweezers, the so-called “tweezer sign” (Robles, in press). It is important to ask patients if they use instruments in addition to fingernails because in our experience, the use of mechanical devices portends a more malignant psychological profile.
Morgellons disease has received recent attention, primarily through the internet and through the website of Morgellons Research Foundation (http://www.morgellons.org). The Morgellons Research Foundation claims that this condition is an emerging infectious disease , however, no available evidence exists to confirm this hypothesis. Some authors affiliated with the Morgellons Research Foundation claim that Lyme Borreliosis  has an association but this has not been substantiated.
There are no data available describing the prevalence of this syndrome. It may be seen in association with a number of psychiatric conditions including unipolar and bipolar depression, schizophrenia and abuse of drugs .
There are no randomized control studies to establish the recommended treatment of this disorder. Some experts discuss the importance of establishing patient rapport by referring to the delusions as Morgellons disease . After ruling out an organic cause, emphasis should be placed on how disconcerting the symptoms must be for the patient.
Medication trials have been intermittently effective. Pimozide has been used in doses of 0.5-2.0 mg daily. Koblenzer believes that Pimozide, with the added anti-pruritic effect, is a preferred treatment . The use of atypical antipsychotics such as risperdal, olanzapine and aripiprazole may also be of benefit [21, 23]. In our experience, the use of extra-thin hydrocolloid dressings over the ulcerations is generally very effective because it provides a mechanical barrier to manipulation and facilitates wound healing. The wounds frequently become secondarily infected, making the use of topical or systemic antibiotics an important adjunctive measure.
21. Koblenzer CS: The challenge of Morgellons disease. J Am Acad Dermatol 2006; 55(5): 920-2.