Still more evidence that Morgellons disease is most likely delusional parasitosis

ResearchBlogging.orgOne of the stranger Internet-based quackery phenomena of the last decade is Morgellon’s disease. This is a topic I haven’t visited that much on this blog, its having last come up in a big way a little more than a year ago, when I discussed it in the context of Dr. Rolando Arafiles and the other quackery he was promoting. This led to extreme unhappiness on the part of self-proclaimed Morgellons disease “expert” Marc Neumann, who later bombarded me with threatening e-mail rants. In any case, whatever Morgellons disease is, its cause is almost certainly not what patients think it is, namely the presence of tiny organisms in the skin leading to a chronic itch that leads to chronic scratching. Its adherents describe it thusly:

Morgellons is a multi-symptom disease that is just now starting to be researched and understood. It has a number primary symptoms:


  • Sponanteously Erupting Skin lesions
  • Sensation of crawling, biting on and under the skin
  • Appearance of blue, black or red fibers and granules beneath and/or extruding from the skin
  • Fatigue


  • Short-term memory loss
  • Attention Deficit, Bipolar or Obsessive-Compulsive disorders
  • Impaired thought processing (brain fog)
  • Depression and feelings of isolation

It is frequently misdiagnosed as Delusional Parasitosis or an Obsessive Picking Disorder.

Except that delusional parasitosis is probably not a misdiagnosis. The “fibers” or “granules” found in the skin virtually always turn out to be consistent with fibers from clothing or other sources. At least, no advocate of Morgellons disease has ever demonstrated them to be anything mysterious. This concept has led to treatments for Morgellons that resemble those of chronic Lyme disease, namely chronic antibiotic use. Indeed, interestingly, Morgellons advocates frequently link Lyme disease to Morgellons, with some even asking whether Morgellons disease is the “Lyme disease of our time.”

I was reminded of this frustrating (for both patient and physician) phenomenon by a couple of things recently. First, Mark Crislip wrote an excellent discussion of Morgellons disease and delusional parasitosis (which, of course, appear to be basically the more or less the same thing). The second was the publication of a study in the Archives of Dermatology by a group from the Mayo Clinic entitled Delusional Infestation, Including Delusions of Parasitosis: Results of Histologic Examination of Skin Biopsy and Patient-Provided Skin Specimens. Basically, what investigators Hylwa et al did was something very obvious. They retrospectively reviewed the pathology results of patient-provided specimens and physician-ordered skin biopsies in patients with Morgellons and diagnoses akin to Morgellons. Their search strategy was as follows:

A computerized search of patients seen at Mayo Clinic’s site in Rochester, from 1996 through 2007, was performed using the following search terms: delusion of lice, delusional disorder with parasitosis, delusion(s) of parasitosis, delusional parasitosis, delusion(s) of parasitism, delusion(s) of parasites, parasitosis (delusional), delusional infestation, delusory parasitosis, psychogenic parasitosis, neurogenic parasitosis, neurotic parasitosis, Ekbom syndrome, formication and parasites, chronic tactile hallucination(s), dermatophobia, parasitophobia, toxic psychosis, tactile psychosis, monosymptomatic hypochondriacal psychosis, Morgellon(s), psychogenic dermatitis, neurotic dermatitis, neurogenic dermatitis, self-induced excoriations, and psychogenic excoriations.

From this, the authors chose cases thusly:

All patients who were seen at Mayo Clinic and whose final assessment was consistent with the criteria for diagnosis of delusional skin infestation as described by Freudenmann and Lepping12 were identified as having the disorder and were evaluated for inclusion in this study. The 2 inclusion criteria were (1) the patient’s conviction that he or she was being infested by pathogens (animate [eg, insects or worms] or inanimate [eg, fibers]) without any medical or microbiological evidence for this, ranging from overvalued ideas to a fixed, unshakable belief; and (2) the patient’s complaint of abnormal sensations in the skin explained by the first criterion. When a diagnosis was uncertain, the case was discussed between the reviewers and a final decision to include or exclude the patient was agreed between them.

The general term delusional infestation was chosen because it embraces the 2 main categories in which patients present: delusions that they are infested with animate material (such as parasites) and delusions that they are infested with inanimate material (such as fibers).

So what were the results?

Basically, out of the 80 cases of patients who underwent skin biopsy, Hylwa et al found not a single patient had objective evidence of parasite infestation on skin biopsy, although 61% did reveal dermatitis, including 33 cases of chronic dermatitis, 10 cases of subacute, and 6 cases of lichen simplex chronicus. This last diagnosis is a thickening of the skin with scaling that arises secondary to repetitive rubbing or scratching. In actuality, I’m rather surprised that only 60% of biopsies showed this result; I would have expected it to be higher. I am not surprised that the skin biopsies were in essence nondiagnostic. A number of patients had skin cultures. These, too, were all nondiagnostic, being either negative or yielding common contaminating organisms that couldn’t possibly account for the patients’ symptoms.

Also not unexpected are the results of examinations of patient-provided specimens. These were examined by dermatologists, pathologists, tropical medicine specialists, internal medicine doctors, psychiatry, or infectious disease physicians like Dr. Crislip. Most commonly, they were found to be skin flakes or serum crust, hair, or textile fibers. There were a couple of insects found among the specimens. One of them was interesting in that it was an actual parasite, specifically a pubic louse, but physical examination showed no evidence of infestation. Another patient brought in a tick, but the clinical judgment of the practitioners was that the tick could not account for the patient’s symptoms. The bottom line is that none of the patient-provided specimens resulted in any useful information other than that the patient did not have parasites. Consistent with the scientific literature on Morgellons disease, they were nothing consistent with a diagnosis of parasite infestation.

The authors point out that this is to the best of their knowledge the first study that addressed the histological analysis of skin biopsies and patient-provided specimens in a relatively large number of patients. They also note, as you would expect, that this is a retrospective study, and thus prone to all the shortcomings of retrospective studies, including the potential for incomplete information and bias. One aspect that the investigators mention that isn’t really a bug (if you’ll excuse the term) but a feature is that the patients had “disparate characteristics, with an array of presentations.” That’s pretty much the definition of Morgellons; it consists of an array of nonspecific symptoms that focus around the belief that something has infested the skin, be it parasites or some sort of inanimate contaminants, and disparate presentations would be expected. Be that as it may, the authors ended up concluding that examination of patient-provided specimens and skin biopsies showed no evidence of infestation, although they did frequently show evidence of dermatitis. Unfortunately, this is a nonspecific finding; it’s also difficult to figure out whether the dermatitis is a cause of the sensation of infestation or occurs as a result of it and the scratching and rubbing that such patients engage in. Indeed, the authors ask:

The results of this study raise many questions concerning the value of skin biopsies in the context of a patient pre- senting with delusional infestation. Given that a skin biopsy and histologic examination of specimens brought by patients do not yield evidence of infesting materials, either animate or inanimate, should a biopsy be performed? Some have proposed that an alliance with a patient is a justification for a skin biopsy, but is it? What is the outcome fol- lowing a biopsy? Did it improve the outcome of the inter- action with the patient? Were patients more likely to be compliant with therapy following a biopsy? These questions remain unanswered by this study, which concentrated on the results of skin biopsies in this situation.

It’s a difficult set of questions. This study would suggest that the diagnostic yield of doing such biopsies is incredibly low. So, what reason is there to do a skin biopsy in cases like this? If this study is to be believed, the answer is: None.

Overall, this study also provides still more evidence, as if any were needed, that patients with the constellation of symptoms consistent with Morgellons disease and/or delusional parasitosis (which appear to be more or less the same thing) rarely, if ever, have any specific findings consistent with real parasitic infestations of the skin, their belief that they are somehow infested notwithstanding. Many of them have some form of dermatitis, but it is not clear whether it is the primary explanation for their symptoms or occurs as a result of the scratching that these patients engage in. Whatever the case, I have no doubt that these patients are suffering, but the explanations proffered by advocates of Morgellons as the cause of their symptoms. Unfortunately, this study is highly unlikely to change the minds of patient advocacy groups promoting Morgellons disease as an entity, just as numerous studies failing to support the idea of chronic Lyme disease have failed to convince patient advocacy groups that chronic antibiotic therapy for the constellation of symptoms attributed to chronic Lyme disease is not a good idea. It should also be noted that delusional parasitosis existed as a distinct diagnosis before Morgellons disease, which has only come to the fore over the last decade or so.

One thing that is sure. The promotion of Morgellons disease as a distinct disease, primarily by means of Internet-fueled advocacy and old-fashioned conspiracy mongering. What these patients need is the application of science and science-based medicine to their problem, not the various quack nostrums sold to them by practitioners who are either unscrupulous or themselves share the delusion. This study adds to our knowledge by providing yet more evidence that there is rarely, if ever, a documented parasitic infestation in these patients.


Hylwa, S., Bury, J., Davis, M., Pittelkow, M., & Bostwick, J. (2011). Delusional Infestation, Including Delusions of Parasitosis: Results of Histologic Examination of Skin Biopsy and Patient-Provided Skin Specimens Archives of Dermatology DOI: 10.1001/archdermatol.2011.114