Delusions of Parasitosis

Morgellons / Delusional Infestation

Overview

Delusions of parasitosis (delusional infestation) is a psychiatric condition in which a person has an unshakable, false belief that they are infested with parasites, insects, or other organisms crawling on or under their skin. Patients often present with self-inflicted excoriations and may bring specimens of skin debris, lint, or scabs (the 'matchbox sign' or 'specimen sign') to prove the infestation. No actual parasites are present. The condition requires a sensitive, nonjudgmental approach.

Key Symptoms

  • Intense crawling, biting, stinging, or itching sensations on or under the skin
  • Self-inflicted excoriations, erosions, and ulcers from scratching and picking
  • Patient brings specimens (lint, debris, scabs) believing they are parasites (matchbox sign)
  • Firm, unshakable conviction of infestation despite negative medical workup
  • May use excessive cleaning products, pesticides, or home remedies that cause further skin damage
  • Social isolation and significant functional impairment due to the perceived infestation

Affected Areas

Arms, Legs, Face, Scalp, Trunk, Any area the patient can reach to scratch

Care Instructions

  1. See a dermatologist who can perform a thorough evaluation to rule out true infestation and other causes of itch.
  2. Establish a trusting therapeutic relationship — do not dismiss the patient's concerns.
  3. Antipsychotic medication (such as risperidone or pimozide) is the most effective treatment.
  4. Wound care for self-inflicted lesions to prevent secondary infection.
  5. Treat any co-existing medical causes of pruritus (thyroid disease, liver disease, iron deficiency).
  6. Psychiatric or psychological referral may be beneficial, though patients are often reluctant.

Medical Disclaimer: This information is for educational purposes only and does not replace professional medical advice. Always consult a qualified dermatologist for diagnosis and treatment.

Prevalence: Uncommon; estimated incidence of 20 per million per year, more common in women over 50