Public Health Strategies for Crusted Scabies Outbreaks in Institutional Settings

Key points

  • Crusted scabies is a severe form of scabies that is extremely contagious.
  • Prompt diagnosis and treatment of crusted scabies is important to prevent complications and outbreaks.
  • Patients with crusted scabies may not show the usual signs, symptom, or lesion distribution seen in classic scabies.


Local and/or state health departments may be able to provide guidelines for preventing and controlling scabies outbreaks.

Below are suggestions for developing guidelines for preventing, detecting, and responding to a single case or multiple cases of crusted scabies (formerly known as Norwegian scabies) in an institution.


Early detection, treatment, and implementation of appropriate isolation and infection control practices are essential in preventing scabies outbreaks. Institutions should maintain a high index of suspicion that undiagnosed skin rashes and conditions may be scabies, even if characteristic signs or symptoms of scabies are absent (e.g. no itching).

New patients and employees should be screened carefully and evaluated for any skin conditions that could be compatible with scabies. The onset of scabies in a staff person who has had scabies before can be an early warning sign of undetected scabies in a patient/resident.

When there is concern for scabies in a person, skin scrapings should be obtained and examined carefully by a person who is trained and experienced in identifying scabies mites. Appropriate isolation and infection control practices (e.g. gloves, gowns, avoidance of direct skin-to-skin contact, etc.) should be used when providing hands-on care to patients/residents who might have scabies. Epidemiologic and clinical information about confirmed and suspected scabies patients/residents should be collected and used for systematic review in order to facilitate early identification of and response to potential outbreaks.


Establish surveillance.

  • Have an active program for early detection of infested patients/residents and staff; unrecognized crusted scabies is frequently the source of institutional scabies outbreaks.
  • Maintain a high index of suspicion that scabies may be the cause of undiagnosed skin rash; evaluate and confirm suspected cases by obtaining skin scrapings; persons with crusted scabies may not show the characteristic symptoms of scabies such as rash and itching (pruritus).
  • Screen all new patients/residents and staff for scabies.
  • Notify the local health department of the outbreak; determine if there is evidence of an increase in scabies cases in the community; notify other institutions to or from which infected or exposed patients/residents may have transferred.
  • Maintain ongoing surveillance for scabies among all patients/residents and staff to identify new or unsuccessfully treated cases of scabies.

Diagnostic Services

Ensure that adequate diagnostic services are available.

  • Consult with an experienced dermatologist for assistance in differentiating between skin rashes and scabies.
  • Ensure a trained and experienced staff member can obtain and examine skin scrapings to identify scabies mites.

Control & Treatment

Establish appropriate procedures for infection control and treatment.

  • People infected with crusted scabies have very large numbers of mites; this increases the risk of transmission both from brief skin-to-skin contact and from contact with items such as bedding, clothing, furniture, rugs, carpeting, floors, and other fomites that can become contaminated with skin scales and crusts shed by the infested person.
  • Maintain records with patient name, age, sex, room number, roommate(s) name(s), skin scraping status and result(s), and name(s) of all staff who provided hands-on care to the patient/resident before implementation of infection control measures: symptoms can take up to 2 months to appear in exposed persons and staff.
  • Use epidemiologic data about the distribution of confirmed cases by building, room, floor, wing, occupation (for staff), dates of admission, and onset of scabies-like condition to determine:
  1. levels of risk for patients/residents and staff;
  2. extent of the outbreak (e.g., confined or widespread in the facility); and
  3. temporal relationship among cases.
  • Use contact precautions with protective garments (e.g., gowns, disposable gloves, shoe covers) when providing care to any patient with crusted scabies until successfully treated; wash hands thoroughly after providing care to any patient.
  • Isolate patients with crusted scabies from other patients/residents who do not have crusted scabies; consider assigning a cohort of caretakers to care only for patients/residents with crusted scabies.
  • Maintain contact precautions until skin scrapings from a patient with crusted scabies are negative.
  • Limit visitors for patients with crusted scabies; visitors should use the same contact precautions and protective clothing as staff.
  • Identify and treat all patients/residents, staff, and visitors who may have been exposed to a patient/resident with crusted scabies or to clothing, bedding, furniture, or other items (fomites) used by a patient/resident with crusted scabies; strongly consider treatment even in equivocal circumstances because controlling an outbreak involving crusted scabies can be very difficult and risk associated with treatment is relatively low.
  • Offer treatment to household members (e.g., spouses, children, roommates) of staff who are undergoing scabies treatment.
  • Treat patients/residents, staff, and household members at the same time to prevent reexposure and continued transmission.
  • Staff generally can return to work the day after receiving a dose of treatment with permethrin or ivermectin; however, symptomatic staff who provide hands-on care to any patient/resident may need to use disposable gloves for several days after treatment until sure they are no longer infested.
  • Use procedures that minimize risk of transmission of secondary bacterial infections that may develop with scabies.

Environmental Disinfection

Establish appropriate procedures for environmental disinfection.

  • Ensure bedding and clothing used by a person with crusted scabies is collected and transported in a plastic bag and emptied directly into washer to avoid contaminating other surfaces and items; machine wash and dry all items using the hot water and high heat cycles (temperatures in excess of 50°C or 122°F for 10 minutes will kill mites and eggs); ensure laundry personnel use protective garments and gloves when handling contaminated items.
  • Items that cannot be laundered can be disinfested by storing in a closed plastic bag for several days to a week. Scabies mites generally do not survive more than 2 to 3 days away from human skin.
  • Attempt to ensure that all persons who receive treatment have the clothing and bedding they used anytime during the three days before treatment machine-washed and dried using hot water and high heat cycles. Temperatures in excess of 50°C or 122°F for 10 minutes will kill mites and eggs.
  • Clean the room of patients/residents with crusted scabies regularly to remove contaminating skin crusts and scales that can contain many mites.
  • Thoroughly clean and vacuum the room when a patient/resident with crusted scabies leaves the facility or moves to a new room.
  • Mattresses do not usually need to be discarded.

Communication strategies

  • Establish procedures for identifying and notifying at-risk patients/residents and staff who are no longer at the institution.
  • Ensure a proactive employee health service approach to scabies. Include information about scabies to all staff and provide dermatologic consultation for employees and, when appropriate, their household members.
  • Maintain an open and cooperative communication between management and staff.