Diagnosis and treatment of delusional parasitosis is challenging and requires great patience. Early on in the diagnosis, it is essential that a trained entomologist or parasitologist be consulted to rule out the presence of actual parasites.

1. Take careful and tactful case histories.
2. Run appropriate diagnostic tests to rule out other medical conditions. (In the case of secondary organic delusional parasitosis the delusion often disappears when the underlying organic illness is treated.)
3. Do a complete physical examination and laboratory evaluation, including:
   • Skin scrapings and biopsies
   • Complete blood count
   • Chemistry profile
   • Thyroid function tests
   • Vitamin B12 levels
4. Rule out true infestations.
5. Rule out other organic causes such as allergies or contact dermatitis.
6. Determine whether there is a history of drug abuse.