From the Guidelines
After treatment for scabies, you are no longer contagious 24 hours after completing the first treatment, but it's crucial to complete the full treatment course to ensure all mites are dead, which typically takes 8-14 days. The standard treatment involves applying permethrin 5% cream (Elimite) from neck to toes, leaving it on for 8-14 hours, then washing it off, and repeating this process after 7 days 1. Alternatively, oral ivermectin (200 mcg/kg, repeated in 7 days) can be used. It's essential to note that even after proper treatment, itching may persist for 2-4 weeks due to allergic reactions to the dead mites. To prevent reinfection, it's recommended to:
- Wash all clothing, bedding, and towels used in the past 3 days in hot water and dry on high heat
- Vacuum your home thoroughly and discard the vacuum bag
- Treat close contacts simultaneously, even if they don't have symptoms, as they may be infected without showing signs 1 Key considerations for returning to work or school include avoiding close physical contact until the full treatment course is complete. The scabies parasite can survive on clothing for up to 4 days without skin contact, highlighting the importance of proper hygiene and laundry practices 1.
From the FDA Drug Label
DOSAGE AND ADMINISTRATION Adults and children Thoroughly massage Permethrin Cream, 5% into the skin from the head to the soles of the feet. ... ONE APPLICATION IS GENERALLY CURATIVE. The answer to how contagious you are after treatment for scabies is not directly addressed in the provided drug label. Key points:
- The label states that one application is generally curative, but it does not provide information on when a person is no longer contagious after treatment.
- It mentions that demonstrable living mites after 14 days indicate that retreatment is necessary, but it does not specify when a person can be considered non-contagious. 2
From the Research
Contagiousness of Scabies After Treatment
The contagiousness of scabies after treatment depends on the effectiveness of the treatment and the time frame considered.
- According to 3, two applications of topical ivermectin provided a cure rate of 64.7% at the 2-week follow-up, which increased to 82.3% at the 4-week follow-up after repeating the treatment.
- In another study 4, two applications of topical ivermectin provided a cure rate of 63.1% at the 2-week follow-up, which increased to 84.2% at the 4-week follow-up after repeating the treatment.
- A study comparing the efficacy of topical permethrin, crotamiton, and sulfur ointment in the treatment of scabies found that at the end of a 4-week interval, the applied treatment was effective in all studied individuals 5.
- Topical permethrin is considered the most effective treatment for classic scabies, with a strength of recommendation of A, based on meta-analyses with consistent results 6.
- A Cochrane review of interventions for treating scabies found that topical permethrin appears to be the most effective treatment for scabies, with fewer treatment failures occurring by day seven compared to other treatments 7.
Factors Affecting Contagiousness
Several factors can affect the contagiousness of scabies after treatment, including:
- The type and effectiveness of the treatment used
- The time frame considered, with most treatments showing higher cure rates at 4-week follow-up compared to 2-week follow-up
- The presence of skin-to-skin contact with an infected individual
- The use of preventive measures, such as washing and drying clothing and bedding, to reduce the risk of transmission
Treatment Options
Various treatment options are available for scabies, including:
- Topical permethrin, considered the most effective treatment for classic scabies
- Topical ivermectin, an effective oral treatment
- Crotamiton, a cost-less alternative to permethrin cream
- Sulfur ointment, effective in treating scabies, but may have a slower onset of action compared to permethrin cream.