Lice

Head lice (Pediculus humanus capitis) are parasitic insects that infest the scalp, feeding on small amounts of blood and causing persistent itching. Transmission occurs primarily through direct head-to-head contact, making school-age children particularly vulnerable. Common signs include visible nits attached to hair shafts, irritated bite marks behind the ears, and a tickling sensation on the scalp. First-line treatments include over-the-counter permethrin or pyrethrin-based pediculicides applied according to package directions. For resistant cases, a dermatologist may prescribe ivermectin, spinosad, or malathion solutions. Thorough combing with a fine-toothed nit comb remains essential to remove surviving eggs and prevent reinfestation.