From the Guidelines
Scabies is highly contagious until treatment is completed, and you can spread it through direct, prolonged skin-to-skin contact with others until you've completed the full treatment course. The standard treatment is permethrin 5% cream applied to the entire body from the neck down, left on for 8-14 hours, then washed off, as recommended by the 2015 guidelines for sexually transmitted diseases treatment 1. This treatment should be repeated after 7 days. Alternatively, oral ivermectin (200 mcg/kg, repeated after 1-2 weeks) may be prescribed, especially in cases of crusted scabies or in institutional settings where outbreaks occur 1. You remain contagious until both treatments are completed.
All household members and close contacts should be treated simultaneously, even if they don't have symptoms, to prevent further transmission, as emphasized in the management of outbreaks in communities and institutional settings 1. Additionally, you should wash all clothing, bedding, and towels used in the past 3 days in hot water and dry on high heat. Items that can't be washed should be sealed in plastic bags for at least 72 hours. Scabies spreads easily because the mites that cause it can live on your skin for 1-2 months, burrowing and laying eggs, before symptoms like intense itching (especially at night) and a rash appear. Even after successful treatment, itching may persist for 2-4 weeks due to allergic reactions to the dead mites.
It's also important to consider special populations, such as infants, young children, and pregnant or lactating women, who may require different treatment approaches, with permethrin being the preferred treatment for these groups due to its safety profile 1. Furthermore, individuals with HIV infection or other immunosuppressed conditions are at increased risk for crusted scabies and should be managed in consultation with a specialist 1.
In terms of contagion, scabies can be transmitted primarily through person-to-person contact, and the scabies parasite can survive on clothing for up to 4 days without skin contact, as noted in the context of infectious diseases associated with organized sports and outbreak control 1. Therefore, prompt and thorough treatment, along with proper hygiene and contact precautions, is crucial to prevent the spread of scabies and manage outbreaks effectively.
From the Research
Contagiousness of Scabies
- Scabies is a highly contagious, globally prevalent, parasitic skin infestation caused by Sarcoptes scabiei var. hominis, also known as the itch mite 2.
- The disease can spread quickly through direct skin-to-skin contact, and both symptomatic patients and asymptomatic carriers can transmit the disease 2.
- Scabies outbreaks have occurred not only in developing countries but also in developed countries among refugees and asylum seekers, highlighting its contagious nature 2.
Transmission and Prevention
- The transmission of scabies can be prevented by identifying risk factors for exposure, isolating patients until after treatment, and informing local public health authorities and hospital infection prevention when necessary 2.
- Measures to prevent the spread of scabies are essential, given its prevalence and contagiousness 2.
- Environmental strategies to control fomite-related reinfestation are also recommended, particularly in cases of childhood classic scabies and their contacts 3.
Treatment and Management
- Treatment of scabies involves using topical or systemic scabicides and treating secondary bacterial infections, if present 2.
- Topical permethrin and oral ivermectin are effective treatments for scabies, with permethrin having a rapid onset of action 4.
- A combination of permethrin and ivermectin can be used to treat otherwise intractable cases, and is generally indicated for the treatment of crusted scabies 5.
- Oral ivermectin is safe, easier to use, cheaper, more effective, and more economical than topicals in widespread institutional scabies, for those nonadherent to topicals, and in crusted scabies 6.