What is the drug of choice for scabies?

From the Guidelines

Permethrin 5% cream is the drug of choice for treating scabies. The standard regimen involves applying the cream to all areas of the body from the neck down and washing it off after 8-14 hours, as recommended by the Centers for Disease Control and Prevention 1.

Key Considerations

• The treatment should be applied to the entire body from the neck down, and for children and infants, it should also include the scalp, neck, face, and ears.
• A second application is typically recommended one week later to ensure that newly hatched mites are killed.
• Permethrin is preferred due to its high efficacy, low toxicity, and good tolerability, with a mechanism of action that disrupts the sodium channels in the parasite's nervous system, leading to paralysis and death of the mites.

Alternative Treatments

• Alternative treatments, such as ivermectin (an oral medication), benzyl benzoate 25% lotion, or crotamiton 10% cream, are considered when permethrin fails or is contraindicated.
• It is crucial to treat all close contacts simultaneously, even if they are asymptomatic, to prevent reinfection.

Prevention of Reinfestation

• All clothing and bedding should be washed in hot water and dried on high heat to prevent reinfestation. The choice of permethrin as the first-line treatment is based on its effectiveness and safety profile, as outlined in guidelines such as those from 1998 by the Centers for Disease Control and Prevention 1.

From the FDA Drug Label

Permethrin Cream, 5% is indicated for the treatment of infestation with Sarcoptes scabiei (scabies). The drug of choice for scabies is permethrin (TOP), as it is specifically indicated for the treatment of scabies infestation 2.

• The treatment typically involves a single application of permethrin cream, 5% from the head to the soles of the feet, left on for 8 to 14 hours before being washed off 2.
• Permethrin has been shown to be effective in treating scabies, with one application generally being curative 2.

From the Research

Treatment Options for Scabies

• The treatment of choice for common scabies is topical permethrin 5% cream applied for 8-12 hours 3
• Permethrin can be considered for off-label use also in infants of less than 3 months of age and pregnant women 3
• Crotamiton is another option, which, besides benzyl benzoate, presents a good second line therapy for other indications 3
• Indications for oral ivermectin include patients with immunosuppression, severe dermatitis, and low adherence 3
• Crusted scabies is preferentially treated by a combination of topical permethrin and oral ivermectin 3

Efficacy of Treatment Options

• A study compared the therapeutic efficacy of single application of topical 5% permethrin with oral ivermectin (200 μg/kg/dose) in a single-dose and a two-dose regimen in patients with scabies, and found that all three treatment modalities were equally efficacious 4
• Another study compared the efficacy and safety of topical permethrin, topical ivermectin, and oral ivermectin in patients of uncomplicated scabies, and found that permethrin and topical ivermectin were equally effective against scabies while oral ivermectin was significantly less effective up to 2 weeks 5
• A study published in 2003 found that permethrin 5% cream seems slightly superior to lindane and less toxic, and more efficient than crotamiton 6
• A study published in 2019 found that first-line treatment for scabies is permethrin 5% cream 7

Special Considerations

• In cases of keratotic scabies, ivermectin seems interesting with two applications within 1 week, and should be associated with local treatment (duration remains to be defined) 6
• Ivermectin is probably useful in institutional epidemic, and therapeutic attitude remains to be defined 6
• Treatment must be adapted case-by-case, according to feasibility, and it is still important to treat contacts, and modality of this treatment remains to be specified 6