The Sufferer:

• Has suffered from the infestation for a long time.
• Has been seen by numerous physicians, exterminators, parasitologists, hygienists and entomologists.
• Consistently and fiercely rejects negative findings or any that deviate from their perceptions of the infestation.
• May exhibit the "matchbox sign", where sufferers deliver or mail containers holding samples consisting of dust, lint, skin scrapings, toilet paper, dried blood or scabs, hair or other pieces of human tissue.
• May engage in self mutilation, ranging from scratches to deep ulceration. These can occur where the patient has attempted to dig out the parasites.
• Uses home remedies and distrusts of prescription drugs.
• Has exposed themselves to often dangerous levels of pesticides.

One or More "Familiy Members" May Share The Delusion:

• Folie à deux - two family members involved, usually husband and wife or parent and child.
• Folie à partagee - three or more family members involved.

The infestation is described by the sufferer as located:

• In, on or under the skin
• Around or just inside body openings or in sputum.
• Internally, particularly in the stomach or intestines.
• In the vicinity of the sufferer, particularly in the home.