From the Guidelines
Asymptomatic scabies should be treated promptly with permethrin 5% cream to prevent transmission and reduce the risk of morbidity and mortality associated with scabies infestation. Asymptomatic scabies occurs when a person is infected with the Sarcoptes scabiei mite but doesn't show typical symptoms like intense itching or visible skin lesions. According to the Centers for Disease Control and Prevention guidelines 1, scabies in adults may be sexually transmitted, and asymptomatic carriers can still transmit the disease.
The treatment for asymptomatic scabies is the same as for symptomatic cases, and the first-line 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 recent clinical guidelines. This application should be repeated after 7-10 days. Alternative treatments include ivermectin (oral medication, 200 mcg/kg, repeated after 1-2 weeks), benzyl benzoate 25% lotion, or crotamiton 10% cream.
Key considerations in managing asymptomatic scabies include:
- Treating all close contacts, including household members and sexual partners, simultaneously even if asymptomatic to prevent reinfestation
- Washing all clothing, bedding, and towels used by the infected person in hot water and drying them on high heat or sealing them in plastic bags for at least 72 hours to kill the mites
- Recognizing that asymptomatic carriers are still contagious as the female mites continue to burrow into the skin and lay eggs, perpetuating the infestation cycle even without visible symptoms, as noted in studies on scabies transmission 1.
From the Research
Asymptomatic Scabies
- Asymptomatic scabies refers to a condition where an individual is infested with scabies mites but does not exhibit any noticeable symptoms, such as intense pruritus or dermatitis 2.
- The absence of symptoms can make it challenging to diagnose scabies, as the diagnosis is often guided by the presence of thread-like papules, new onset of pruritus, and dermatitis 2.
- There is limited information available on asymptomatic scabies, and most studies focus on the diagnosis and treatment of symptomatic scabies.
Diagnosis and Treatment
- The diagnosis of scabies is typically confirmed by the microscopic or dermatoscopic demonstration of scabies mites 2.
- The first-line therapy for scabies is topical application of permethrin, which is effective in treating the condition 2, 3, 4, 5.
- Other treatment options include systemic ivermectin and topical crotamiton or benzyl benzoate 2, 3, 6.
- The choice of treatment may depend on various factors, including the severity of the infestation, the presence of symptoms, and the patient's medical history.
Treatment Efficacy
- Topical permethrin has been shown to be highly effective in treating scabies, with cure rates ranging from 70% to 100% 3, 4, 5.
- Ivermectin, both topical and systemic, has also been shown to be effective in treating scabies, although its efficacy may vary depending on the study 3, 6.
- Crotamiton and sulfur ointment have also been used to treat scabies, although their efficacy may be lower compared to permethrin and ivermectin 6, 4, 5.