From the Guidelines
Scabies is a contagious skin condition caused by the mite Sarcoptes scabiei, characterized by intense itching and a pimple-like rash, and can be sexually transmitted among adults, as noted in the guidelines from 1 and 1. The symptoms of scabies include pruritus, which is the predominant symptom, and sensitization to Sarcoptes scabiei must occur before pruritus begins, with the first infection taking several weeks to develop, while pruritus may occur within 24 hours after reinfestation, as described in 1 and 1.
Key Characteristics of Scabies
- The mite Sarcoptes scabiei burrows into the skin and lays eggs, causing an allergic reaction and intense itching, especially at night.
- The rash and burrow lines are commonly found between fingers, on wrists, elbows, armpits, waist, buttocks, and genital areas.
- Scabies spreads through prolonged skin-to-skin contact or sharing bedding and clothing with infected individuals.
Management and Treatment
The primary treatment for scabies is permethrin 5% cream, which should be applied from neck to toes and left on for 8-14 hours before washing off, with a second application one week later recommended to kill newly hatched mites, as part of a comprehensive approach to managing the condition, including the examination and treatment of sexual, close personal, or household contacts, as outlined in 1. Alternative treatments include ivermectin (oral medication, 200 mcg/kg, repeated after 1-2 weeks), benzyl benzoate 25% lotion, or crotamiton 10% cream. To prevent reinfestation, all household members should be treated simultaneously, and bedding, clothing, and towels should be washed in hot water and dried on high heat, as recommended in the guidelines from 1. Itching may persist for 2-4 weeks after successful treatment due to allergic reactions to the dead mites.
From the FDA Drug Label
Permethrin Cream, 5% is a topical scabicidal agent for the treatment of infestation with Sarcoptes scabiei (scabies) Scabies is an infestation with Sarcoptes scabiei, a condition that permethrin cream is used to treat 2.
- It is characterized by pruritus, edema, and erythema, and may be accompanied by itching, mild burning, and/or stinging after application of permethrin cream 2.
- The exact definition of scabies is not explicitly stated in the provided drug labels, but it is implied to be a condition caused by the Sarcoptes scabiei parasite.
From the Research
Definition of Scabies
- Scabies is a skin infestation caused by the human itch mite (Sarcoptes scabiei va. hominis) 3.
Causes and Treatment
- It is commonly treated with topical insecticides, but the treatment of choice is still controversial 3.
- Topical permethrin is considered the most effective treatment for classic scabies 4.
- Oral ivermectin is an effective treatment compared with placebo, but not as effective as topical permethrin 4.
Comparison of Treatments
- A study comparing topical ivermectin vs. permethrin 2.5% cream found that 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 3.
- The same study found that treatment with two applications of permethrin 2.5% cream was effective in 65.8% of patients at the 2-week follow-up, which increased to 89.5% at the 4-week follow-up after this treatment was repeated 3.
- A Cochrane Review found that ivermectin was associated with slightly lower rates of complete clearance after 1 week compared with permethrin, but there was no difference in efficacy after 2 weeks 5.