Pediculicidal

Pediculicidal refers to substances or interventions that kill lice (Pediculus humanus) on humans, particularly the head louse (Pediculus humanus capitis) and less commonly body louse. The term is used in contrast to ovicidal agents, which kill the eggs laid by lice. Many treatments are pediculicidal but not reliably ovicidal, so eggs can survive and hatch; therefore retreatment after about 7 to 10 days is commonly recommended to eliminate re-infestation from newly hatched nymphs.

Common pediculicidal treatments include topical neurotoxic insecticides such as permethrin and pyrethrins (often combined with piperonyl butoxide), as well as organophosphate malathion. More recently, physical or non-chemical options such as dimethicone silicone-based products and heat or wet combing have been promoted because they disrupt lice without neurotoxic action. Ivermectin (oral or topical) and spinosad are also used in some regions, especially where resistance to first-line agents is a concern. Benzyl alcohol kills lice by asphyxiation but is not ovicidal.

Safety and usage considerations vary by product and jurisdiction. Treatments are typically approved for use in children above a certain age and may require repeated applications; some products are avoided during pregnancy or in certain medical conditions. It is common practice to treat the person and household contacts, wash clothing and bedding, and thoroughly clean combs and brushes. If infestation persists or multiple family members are affected, medical advice should be sought.