People with<unk>  believe that "parasites, worms, mites, bacteria, fungus" or some other living organism has infected them, and reasoning or logic will not dissuade them from this belief. Details vary among those who have the condition, though it typically manifests as a crawling and pin-pricking sensation that is most commonly described as involving perceived parasites crawling upon or burrowing into the skin, sometimes accompanied by an actual physical sensation (known as formication). Sufferers may injure themselves in attempts to be rid of the "parasites"; resulting skin damage includes excoriation, bruising and cuts, as well as damage caused from using chemical substances and obsessive cleansing routines. A "preceding event such as a bug bite, travel, sharing clothes, or contact with an infected person" is often identified by individuals with<unk> ; such events may lead the individual to misattribute symptoms because of a more awareness of symptoms they were previously able to ignore. Nearly any marking upon the skin, or small object or particle found on the person or their clothing, can be interpreted as evidence for the parasitic infestation, and individuals with the condition commonly compulsively gather such "evidence" to present to medical professionals. This presentation is known as the "matchbox sign", "Ziploc bag sign" or "specimen sign", because the "evidence" is frequently presented in a small container, such as a matchbox. The matchbox sign is present in five to eight out of every ten people with<unk> . Related is a "digital specimen sign", in which individuals bring collections of photographs to document their condition. Similar delusions may be present in close relatives—a shared condition known as a folie à deux—that occurs in 5 to 15% of cases and is considered a shared psychotic disorder. Because the internet and the media contribute to furthering shared delusions,<unk>  has also been called folie à Internet; when affected people are separated, their symptoms typically subside, but most still require treatment. Approximately eight out of ten individuals with<unk>  have co-occurring conditions—mainly depression, followed by substance abuse and anxiety; their personal and professional lives are frequently disrupted as they are extremely distressed about their symptoms. A 2011 Mayo Clinic study of 108 patients failed to find evidence of skin infestation in skin biopsies and patient-provided specimens; the study concluded that the feeling of skin infestation was<unk> .
Delusional parasitosis
Helminthiasis
Acariasis
Soil-transmitted helminthiasis
Schistosomiasis
Toxocariasis
Cyclosporiasis
Isosporiasis