 |
|
Treating Asymptomatic Bodily Contacts of Patients With Scabies
M. Lee Chambliss, MD, MSPH
Moses Cone Family Medicine Residency
1225 Church St
Greensboro, NC 27401-1007
Arch Fam Med. 2000;9:473-474.
QUESTION
Should asymptomatic bodily contacts of a patient with scabies be treated?
SOLUTION
SEARCH STRATEGY
A MEDLINE search was performed (1966-present) on the following medical subject heading (MeSH) terms: scabies + text words: family or household or asymptomatic. Also, the Cochrane Database of Systematic Reviews, general medical and infectious disease textbooks, and the Centers for Disease Control and Prevention Web page were reviewed.
BACKGROUND
Scabies is a common and very irritating, although rarely serious, condition. It is caused by an infestation of the Sarcoptes scabiei mite, an obligate parasite of human skin. Scabies can infect all age groups and can be particularly severe in immunocompromised individuals.1
Scabies is usually transmitted by close or skin-to-skin contact. However, it can be spread by less intimate contact, as illustrated by transmission to nursing personnel and institutional epidemics. Live mites have been found in dust samples and the female mite is thought to be able to live up to 48 hours off human hosts. Authorities disagree about the importance of fomites in scabies transmission. Live mites can live independently of their human hosts for several days. However, there are few documented cases of fomite transmission other than from the unwashed clothing of infected persons.1-2
In immunocompetent individuals, scabies almost always causes intense pruritus, which is often worse at night. The burrowing mite causes erythematous papular eruptions, especially in interdigital and axillary folds, on the wrists and genitalia in men, and at the beltline. It usually spares the head. Threadlike burrows in these areas are the hallmark of the infection. In young children, these classic features are often absent.
Since scabies can be easily transmitted to close contacts, it is logical to assume that treating those contacts will decrease the spread and recurrence of the disease. Unfortunately, there are no trials that have addressed whether treating asymptomatic contacts or family members improves outcomes.3 However, there are 2 areas of indirect evidence that could contribute to an answer to this question.
First, does scabies have a significant asymptomatic stage? Patients who are first exposed to scabies often do not develop symptoms for several weeks.4 In one report detailing the spread of scabies from a hospitalized patient to the nursing staff, the staff did not report symptoms until 3 weeks after exposure.5 Thus, asymptomatic close contacts of infected patients can harbor scabies and should be treated. If a person has been previously exposed to scabies, symptoms develop in a matter of days if they are reinfected.4
Second, how frequently does casual contact transmit scabies? There is a large amount of evidence that close contact, such as sharing the same bed, readily transmits scabies. In reports of transmission to health care workers, exposures have involved close skin-to-skin contact, such as lifting or bathing. A well-documented case report detailed the spread of scabies in a day care center, in which 21% of the staff and children were eventually infected. More than 570 family members of the children also became symptomatic.6 The large amount of skin-to-skin contact involved in caring for children increased the spread of the infection. Most experts seem to agree that for those who do not share clothes or have skin-to-skin or close bodily contact, such as hugging or lifting, the risk of transmission is quite low.
The standard treatment for scabies is 5% permethrin cream applied from the neck down and left on for 8 to 12 hours.7-8 It should be applied to the entire body, including the head, in infants and toddlers. Alternatives include 1% lindane, which should be avoided in children and pregnant women. In adults, ivermectin is effective as a single oral dose. With any regimen, a second treatment maybe warranted if symptoms persist after 2 weeks.
Most authorities recommend that all bedding and clothes be washed in hot water and dried at high heat to kill the parasites. Items that cannot be washed should be stored away from human contact for 4 days. Fumigation is not necessary.4, 7
BOTTOM LINE
Because of its long asymptomatic incubation period and the high level of infectivity, all those with skin-to-skin or close bodily contact with anyone with scabies should be treated, regardless of their symptoms. It is not necessary to treat casual contacts of adult patients with scabies. If a child is infected, it is prudent to treat all family members who have any contact with the patient.
REFERENCES
|
1. Wilson BB. Scabies. In: Mandell GL, Bennett JE, Mandell DR, eds. Douglas and Bennett's Principles and Practice of Infectious Diseases. 4th ed. New York, NY: Churchill Livingstone Inc; 1995:2560-2562.
2. Darmstadt GL. Infestations. In: Behrman RE, Kleigman RM, Jenson HB, eds. Nelson Textbook of Pediatrics. 15th ed. Philadephia, Pa: WB Saunders Co; 1996:2044-2046.
3. Walker GJA, Johnstone PW for the Cochrane Infectious Disease Group. Interventions for treating scabies [Cochrane Review on CD-ROM]. Oxford, England: Cochrane Library, Update Software; 2000:issue 1.
4. AAP 1997 Red Book: Report of the Committee on Infectious Diseases. 24th ed. Elk Grove Village, Ill: American Academy of Pediatrics. 1997:468-470.
5. Sargent SJ, Martin JT. Scabies outbreak in a day-care center. Pediatrics. 1994;94(6, pt 2):1012-1013.
6. Patient-source scabies among hospital personnel—Pennsylvania. MMWR Morb Mortal Wkly Rep. 1983;32:489-490.
PUBMED
7. Centers for Disease Control and Prevention. 1998 guidelines for treatment of sexually transmitted diseases. MMWR Morb Mortal Wkly Rep. 1998;47(RR-1):1-111.
8. Drugs for sexually transmitted infections. Med Lett Drugs Ther. 1999;41:85-90.
PUBMED
SECTION EDITOR: M. LEE CHAMBLISS, MD, MSPH
|
