The medical disorder in which a patient has a mistaken belief of being infested by parasites such as mites, lice, fleas, spiders, worms, bacteria, or other organisms is called delusory parasitosis . This belief is based on the sensations felt in the skin that are very real to the sufferer. These sensations of irritation, itching, or of crawling organisms are so real that the victim is driven to believe that something has to be there. Usually, the patient scratches the itches, but they don't go away. More scratching leads to rashes, open wounds and sores, then to possible infections.
Skin conditions can worsen or become much more complicated.
In some cases the parasites appear to be visible to the afflicted person, but they cannot be caught. In an attempt to discover the causative agent, some people will submit pieces of his or her own tissues to medical or other professionals in a desperate attempt to produce samples of the pests. Very often a corollary problem associated with or underlying delusory parasitosis is stress. Delusory parasitosis, however, can become debilitating because it tends to amplify the stress level and, in turn, the condition worsens. Stress is known to be associated with many health problems in Americans.