How to manage scabies, bedbug and body lice infestations

A new review article in JAMA summarizes the pathophysiology, clinical presentation, diagnosis, treatment and prognosis of scabies, bedbug and body lice infestations. It also highlights key questions about these infestations and provides answers for clinicians.Scabies, bedbug and body lice infestations commonly cause pruritus and rash. They are caused by organisms that live on or in the skin, on clothing, or in the environment. About 622 million incident cases of scabies occurred globally in 2021. Data on bedbug infestations are limited. Body lice prevalence ranges from 4.1%–35% among persons experiencing homelessness worldwide.The authors stress that scabies, bedbug and body lice infestations are common. Accurate diagnosis requires taking a history, including social drivers of health (e.g., housing status, living environment) and physical examination. Deadling with scabiesScabies is caused by mites (Sarcoptes scabiei) that burrow into the epidermis. Transmission primarily occurs from prolonged skin-to-skin contact with an individual who has an infestation. Common scabies is characterized by excoriated pruritic papules, plaques and characteristic burrows on finger/toe web spaces, volar wrists, ankles, axillae, buttocks, male genitalia and areolae. Permethrin 5% cream and oral ivermectin (off-label: 200 μg/kg/dose, with 2 doses given 1–2 weeks apart) are first-line treatments for adults. Data are limited on the safety of ivermectin in pregnancy and in children weighing < 15 kg. Both treatments have similar clearance rates by week 2 (74% with permethrin vs 68% with ivermectin; relative risk, 0.91; 95%CI, 0.76–1.08). Treatment failure can occur with oral ivermectin (11.8%; 95%CI, 8.4%–15.4%) and topical permethrin (10.8%; 95%CI, 7.5%–14.5%). Persistent pruritus after scabies treatment may be due to misdiagnosis, inadequate treatment (e.g., incorrect application of topical treatment, failure to receive the second dose of an ovicidal medication), irritant contact dermatitis from topical scabicides, reinfestation or postscabietic pruritus.Dealing with bedbugsBedbugs (Cimex lectularius, Cimex hemipterus) are insects that live on mattresses and furniture. They feed on blood nocturnally, causing linear pruritic erythematous papules. New skin lesions on waking, cohabitants with similar symptoms, and recently residing in a high-occupancy setting should raise suspicion of bedbugs. Skin reactions to most bites resolve after one week without treatment. Symptomatic treatment with midpotency topical corticosteroids and oral antipruritics (e.g., oral antihistamines, gabapentinoids) can be used as needed. Eradication is best performed by pest management professionals, who often use an integrated strategy that combines interventions, which may include temperature extremes (heating or freezing), laundering, vacuuming and insecticides.Dealing with body liceBody lice (Pediculus humanus humanus) are insects found on clothing. They travel to the skin for blood meals. Bites from body lice cause pruritic excoriated macules/papules and hyperpigmentation in areas where clothing seams contact the skin. First-line treatment and prevention involves bathing and laundering clothing and bedding at least once weekly. Clothing and bedding should be machine washed in water that has been heated to at least 130°F (54°C) and then dried using the high-heat cycle. If laundering is not available, clothing and bedding can be sealed in a plastic bag and stored for two weeks. Symptomatic treatment with midpotency topical corticosteroids and oral antipruritics (e.g., oral antihistamines, gabapentinoids) can be used as needed.Reference: Thomas C, Valladares HC, Berger TG, et al. Scabies, bedbug, and body lice infestations. A review. JAMA 2024; published online September 9, 2024. (accessed September 10, 2024).

How to manage scabies, bedbug and body lice infestations

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