CORHA General Guidance for the Outbreak Detection and Reporting of Scabies

Background

The scabies mite, Sarcoptes scabiei, is an ectoparasite that burrows into the upper layer of the skin and deposits eggs which form adults in 10-17 days. On a person, scabies mites can live for as long as 1-2 months. Off a person, scabies mites usually do not survive more than 48-72 hours. An exposed individual can be infectious to others, even in the absence of symptoms, which may not appear until 4-6 weeks after exposure. Scabies can be diagnosed clinically or via skin scraping. Scabies can spread rapidly under crowded conditions where close body contact is frequent.

Outbreak Detection and Reporting

1. The thresholds and definitions below are intended as general guidance, and were based on available resources and expert opinion. States and local jurisdictions may have their own outbreak definitions and requirements for reporting.
   
   • What is the threshold for additional investigation by a facility?
     1. Single case of scabies (non-crusted or crusted) identified[1] in patients or staff (not applicable to outpatient settings).
   • What is the threshold for reporting to public health? (Check with your local & state public health departments to confirm their reporting requirements.)
     1. Single case of crusted scabies identified[1] in patients or staff.
     2. Two cases of non-crusted scabies identified[1] in patients or staff within the facility with an epidemiologic link within a 6-week period of time.
     3. Outpatient or emergency department settings: Single case of crusted or non-crusted scabies[1] in a patient from another facility or other congregate setting.
   • Outbreak Definition
     1. Two cases of non-crusted or crusted scabies identified in patients or staff with an epidemiologic link[2] within a 6-week period of time.
2. How can detection and reporting be improved?
   • Maintain a high index of suspicion that scabies may be the cause of undiagnosed skin rash.
   • Suspected cases should be evaluated, keeping in mind:
     1. Diagnosis of a scabies infestation usually is made based upon the customary appearance and distribution of the rash and the presence of burrows.
     2. Skin scrapings can be performed and used for microscopic identification of the mite or its products. However, a negative skin scraping from a person with typical non-crusted scabies does not rule out scabies infestation.

Key Points for a Successful Investigation

• The incubation for scabies is up to 6 weeks.
• Consider that patients might have acquired the infestation at a facility/location other than the facility making the diagnosis of scabies. Outpatient and emergency department settings may have a unique opportunity to identify patients with scabies coming from a healthcare facility or other shared congregate setting.
• Diagnosis relies on clinical evaluation; skin scraping is highly specific but very insensitive and a negative skin scraping does not exclude a diagnosis of scabies.
• If clinical suspicion for scabies infestation is high, but lab confirmation cannot be obtained, investigation should continue and a decision to proceed with treatment should be considered.
• Treatment, prophylaxis, and environmental cleaning should all be accomplished within the same 24-hour period to prevent re-infestation of treated or prophylaxed individuals.
• During an outbreak, daily patient skin assessments should be performed on the affected unit and documented in the patient’s medical record.
• Scabies outbreak management should include planning for personal protective equipment (PPE) including disposable, long sleeve gowns and gloves, and pharmacy supplies.
• Appropriate application of scabicide medication is essential. Control measures will be compromised if:
  • scabicide application directions are not followed;
  • scabicide is not applied to the entire body;
  • scabicide is not reapplied after it has been removed from the body during the treatment period; or
  • topical steroids are used during the treatment period.

[1] Scabies can be diagnosed clinically or via skin scraping

[2] Epidemiologic link: Including but not limited to the following examples: residing on same unit (or within same facility if facility is smaller), transferred from the same outside facility, assigned to the same primary or consultative service, facility staff in common, had same procedure, etc.

Supplemental Resources:

Centers for Disease Control and Prevention: Parasites

County of Los Angeles Public Health: Scabies Prevention and Control Guidelines Acute and Long-Term Care Facilities, 2015

Michigan Department of Health and Human Services: Scabies Prevention and Control Manual

Source: CORHA Investigation and Control Workgroup
Date Posted: October 2017