The dangers of untreated head lice
Treating head lice is important. Leaving head lice untreated can have serious consequences both for the carrier and for people they meet.
Feb 21, 2026 · 4 min read
TL;DR
Leaving head lice untreated lets them multiply. Itching worsens, the infestation spreads to family and contacts, and scratching can cause skin infection. Treat early with silicone- or oil-based products or wet combing.
Untreated head lice – what happens?
Female lice lay several eggs a day. Without treatment, a small infestation grows quickly. Itching may increase, and constant scratching can lead to sores or secondary bacterial infection. Lice also spread to others through head-to-head contact.
Do lice need to mate to lay eggs?
A single fertilised female can lay viable eggs. That's why one louse can start a new infestation. Treat everyone with confirmed lice at the same time. Repeat treatment after 7–10 days. For stubborn cases, see a professional clinic.