A 22-year-old woman is diagnosed with scabies and prescribed permethrin 5% cream. She is asymptomatic but lives with her husband and two children, all of whom are currently asymptomatic. What is the rationale for treating all household contacts simultaneously?
- A Permethrin resistance is common, so multiple contacts must be treated to prevent selection of resistant mites
- B Scabies is only transmitted through direct skin contact during symptomatic phases
- C The incubation period in untreated contacts is approximately 4-6 weeks, during which they may be asymptomatic carriers ✓
- D Asymptomatic contacts have developed immunity and serve as reservoirs for reinfection
Correct answer: C. The incubation period in untreated contacts is approximately 4-6 weeks, during which they may be asymptomatic carriers
Explanation
In individuals not previously infested, the incubation period for scabies is approximately 4-6 weeks, during which they are asymptomatic but can transmit mites. In previously sensitized individuals, symptoms may appear within 1-4 days. Treating all close contacts simultaneously, regardless of symptoms, prevents the ping-pong effect of reinfection. Fomite transmission is possible but less common than skin-to-skin contact.
Reference: Centers for Disease Control and Prevention Guidelines, 2022 ed.
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Written and medically reviewed by the StethoPrep medical team.