Lice and Scabies: Treatment Update

Karen Gunning, PharmD; Bernadette Kiraly, MD; Karly Pippitt, MD

Disclosures

Am Fam Physician. 2019;99(10):635-642. 

In This Article

Treatment of Pubic and Body Lice

Treatment of pubic lice is similar to that of head lice. The Centers for Disease Control and Prevention recommends permethrin 1% lotion or pyrethrins 0.3%/piperonyl butoxide 4% shampoo as the first-line agent, and malathion 0.5% lotion or oral ivermectin as an alternative.[10] The Centers for Disease Control and Prevention recommends treating sex partners from the previous month, although European guidelines recommend treating partners from the previous three months.[9,10] The mainstay of treatment for body lice involves laundering clothing and bedding in hot water and bathing regularly.

Scabies

Scabies is a common public health problem affecting approximately 100 million persons annually.[24] It is caused by the Sarcoptes scabiei mite (Figure 3). The female mite is approximately 0.4 mm in size. After mating on the skin surface, the male mite dies, and the female burrows under the skin where she lays eggs for four to six weeks.[25,26] Egg production occurs at a rate of one to three eggs daily, and larvae emerge two to three days after the eggs are laid. The larvae reach maturity in about two weeks, and the new mites cut through the burrow to the skin surface to mate and multiply.[25,26] With the first infestation, symptoms may not develop for up to six weeks because there is a delay in the hypersensitivity reaction to mite feces, during which time household contacts may become infected. Symptoms occur more quickly with reinfestations.[25]

Figure 3.

Sarcoptes scabiei (scabies) mite.
Reprinted with permission from the University of Iowa College of Medicine, Department of Dermatology.

Female scabies mites can travel up to 2.5 cm per minute, but they do not jump or fly.[25] After exposure, mites can penetrate the epidermis within 30 minutes. Transmission typically occurs via direct skin-to-skin contact, but there is evidence that mites can survive for days after leaving human skin and be transmitted via fomites (e.g., clothing, linens, towels).[27] About 15 to 20 minutes of close contact is needed to transfer the mite from one person to another.[28] Risk factors for scabies infestation include overcrowded living conditions, poor hygiene, poor nutritional status, homelessness, dementia, sexual contact, and living in a tropical region.[24,26]

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