Delusional Parasitosis is defined as a medical disorder in which the patient has a mistaken belief of being infested by parasites such as mites, lice, fleas, spiders, worms, bacteria, or other organisms. The bases of this belief are sensations 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 rightfully driven to believe that something is there. Usually, the sufferer scratches the itches, but they don't go away. More scratching leads to rashes, open wounds and sores, then infections.
Skin conditions become worse or much more complicated.
In a desperate attempt to find the causative agent, some people mutilate themselves externally and internally. Sometimes the parasites appear to be visible to the afflicted person, but they cannot be caught. The person sometimes will submit pieces of their own tissues to medical or other professionals, in a desperate effort to demonstrate the pests. When no parasites are discovered, the patient's frustration level reaches incredible heights. Delusional parasitosis however can become overwhelming, because it tends to amplify the stress level and, in turn, be increased by stress.