Pediculosis capitis (head lice infestations) occur in all age groups, but especially in elementary school children. In most cases, transmission occurs by head-to-head contact. Pharmacologic treatment is recommended for persons with live lice or eggs (nits) within 1 cm of the scalp. Topical pediculicides should be tried first. Oral therapy is occasionally required for refractory infestations.

The Centers for Disease Control and Prevention (CDC) and the Environmental Protection Agency (EPA) recommend using insect repellents to prevent infections transmitted by mosquitoes and ticks. Insect repellents applied to exposed skin should be used in conjunction with other preventive measures such as wearing pants and long-sleeved shirts and avoiding outdoor activities during peak mosquito-biting times. Mosquitoes can transmit diseasecausing pathogens, including Zika, chikungunya, dengue, West Nile, eastern equine encephalitis, and yellow fever viruses, and the malaria parasite....

Topical ivermectin lotion 0.5% (Sklice, and generics), which has been available by prescription since 2012, is now FDA-approved for sale over the counter (OTC) for treatment of head lice in patients ≥6 months old. Ivermectin is also available by prescription as a 1% cream (Soolantra) approved for topical treatment of inflammatory lesions of rosacea and in oral tablets (Stromectol, and generics) for treatment of various parasitic infections.

This article includes recommendations for management of most sexually transmitted infections (STIs) other than HIV and viral hepatitis. Some of the indications and dosages recommended here have not been approved by the FDA (see Table 1).

The possibility that use of mifepristone (Mifeprex, and generics) may be restricted has led to questions about alternatives for medication abortion.

Lyme disease in the US is caused by the spirochete Borrelia burgdorferi, which is transmitted to humans by Ixodes scapularis (blacklegged [deer] tick) and I. pacificus (western blacklegged tick). Most cases of Lyme disease occur in late spring and early summer in northeastern and mid-Atlantic states, the upper Midwest, and in northern California. B. mayonii, which is also transmitted by I. scapularis, has been shown to cause a similar illness in the upper Midwest.