What is the recommended treatment for scabies using ivermectin (antiparasitic medication)?

From the Guidelines

Ivermectin is an effective treatment for scabies, typically administered as a single oral dose of 200 micrograms per kilogram of body weight, repeated in 2 weeks, as recommended by the 2015 sexually transmitted diseases treatment guidelines 1. The treatment of scabies with ivermectin involves a single oral dose, which is usually repeated after 7-14 days to kill any newly hatched mites. For most adults, this translates to about 12-18 mg per dose, depending on weight. While treating with ivermectin, it's essential to also wash all bedding, clothing, and towels in hot water and dry on high heat to prevent reinfestation, as suggested by the guidelines for managing scabies 1. Close contacts should be treated simultaneously, even if they don't show symptoms, as scabies is highly contagious, and this is recommended for the management of sex partners and household contacts 1. Ivermectin works by paralyzing and killing the Sarcoptes scabiei mites by disrupting their nervous system. It's particularly useful for widespread or severe infestations, crusted scabies, or when topical treatments have failed. Some key considerations for the treatment include:

• The safety of ivermectin in children who weigh <15 kg has not been determined, and therefore, permethrin is the preferred treatment for infants and young children 1.
• Pregnant women, nursing mothers, and children weighing less than 15 kg should avoid ivermectin and use topical treatments instead, due to limited data regarding its use in these populations 1.
• Side effects are generally mild but may include headache, dizziness, or gastrointestinal symptoms.
• Symptoms may persist for 2-4 weeks after successful treatment due to ongoing immune response to dead mites, and retreating 2 weeks after the initial treatment regimen can be considered for those persons who are still symptomatic or when live mites are observed 1.

From the Research

Scabies Treatment with Ivermectin

• Ivermectin is an effective oral scabicidal agent for the treatment of scabies, offering an alternative to topical medications that can be messy and require prolonged application 2.
• A single oral dose of ivermectin, typically 200 μg/kg body weight, has been shown to be very effective in treating human scabies, with a second dose 7-10 days later substantially improving the cure rate 2, 3.
• The use of ivermectin is particularly beneficial in cases of endemic and epidemic scabies in institutions, as well as in patients with crusted scabies, where it can be used in combination with topical scabicides 2, 3.
• Studies have demonstrated the safety and efficacy of ivermectin in treating scabies in infants and young children, including those weighing less than 15 kg, with a mean dose of 223 μg/kg and a systematic second dose given in most cases 4.
• While ivermectin is generally well-tolerated, potential adverse events include the appearance of eczematous cutaneous lesions, which have been reported in some patients following oral ivermectin administration 5.
• The optimal dosing regimen for ivermectin in the treatment of scabies is still a subject of debate, with some studies suggesting that a single 400 μg/kg oral dose may be more effective than a lower dose 5.

Dosage and Administration

• The recommended dosage of ivermectin for scabies treatment is typically 200 μg/kg body weight, given as a single oral dose, with a second dose administered 7-10 days later if necessary 2, 6, 3.
• In some cases, a higher dose of 400 μg/kg may be used, particularly in patients who do not respond to the lower dose 5.
• Ivermectin can be given to infants and young children, including those weighing less than 15 kg, with a mean dose of 223 μg/kg and a systematic second dose given in most cases 4.

Special Considerations

• Crusted scabies, a severe form of the disease, may require combination therapy with ivermectin and topical scabicides 2.
• In institutional settings, such as nursing homes, ivermectin can be an effective treatment for endemic scabies, particularly when used in conjunction with other control measures 3.
• Patients with a history of atopic diathesis or other skin conditions may be more prone to adverse events, such as eczematous eruptions, following ivermectin administration 5.