What is lindane used to treat?

Lindane is an insecticide that is primarily used in the treatment of lice and scabies, making it the correct choice. It works by attacking the nervous system of the parasites, effectively killing them. The formulation of lindane is specifically designed to target the types of pests involved in these conditions, which makes it a suitable treatment option for infestation with lice (pediculosis) and scabies caused by the Sarcoptes scabiei mite.

In contrast, other options do not align with the intended use of lindane. Allergies and skin irritations are typically treated with different classes of medications, such as antihistamines or topical corticosteroids. Worm infestations are usually addressed with anthelmintics, which specifically target intestinal parasites, whereas fungus infections would be treated with antifungal medications. Thus, the specificity of lindane’s action against lice and scabies confirms why this answer is the most appropriate in the context of the question.