per kg body weight), while severe infections are treated with five to seven days of ivermectin. Ivermectin is also the primary treatment for Mansonella ozzardi and cutaneous larva migrans. The U.S. Centers for Disease Control and Prevention (CDC) recommends ivermectin, albendazole, or mebendazole as treatments for ascariasis. Ivermectin is sometimes added to albendazole or mebendazole for whipworm treatment, and is considered a second-line treatment for gnathostomiasis. Mites and insects Ivermectin is also used to treat infection with parasitic arthropods. Scabies – infestation with the mite Sarcoptes scabiei – is most commonly treated with topical permethrin or oral ivermectin. A single application of permethrin is more efficacious than a single treatment of ivermectin. For most scabies cases, ivermectin is used in a two dose regimen: a first dose kills the active mites, but not their eggs. Over the next week, the eggs hatch, and a second dose kills the newly hatched mites. The two dose regimen of ivermectin has similar efficacy to the single dose permethrin treatment. Ivermectin is, however, more effective than permethrin when used in the mass treatment of endemic scabies. For severe "crusted scabies", where the parasite burden is orders of magnitude higher than usual, the U.S. Centers for Disease Control and Prevention (CDC) recommends up to seven doses of ivermectin over the course of a month, along with a topical antiparasitic. Both head lice and pubic lice can be treated with oral ivermectin, an ivermectin lotion applied directly to the affected area, or various other insecticides. Ivermectin is also used to treat rosacea and blepharitis, both of which can be caused or exacerbated by Demodex folliculorum mites. Contraindications The only absolute contraindication to the use of ivermectin is hypersensitivity to the active ingredient or any component of the formulation. In children under the age of five or those who weigh less than , there is limited data regarding the efficacy or safety of ivermectin, though the available data demonstrate few adverse effects. However, the American Academy of Pediatrics cautions against use of ivermectin in such patients, as the blood-brain barrier is less developed, and thus there may be an increased risk of particular CNS side effects such as encephalopathy, ataxia, coma, or death. Such patients should be monitored very closely when given ivermectin. The American Academy of Family Physicians also recommends against use in these patients, given a lack of sufficient data to prove drug safety. Ivermectin