Lice: where do they come from and how to remove them?

Lice: where do they come from and how to remove them? - briefly

Lice are obligate parasites spread primarily through direct head‑to‑head contact or by sharing items such as combs, hats, and bedding. Eradication relies on a certified pediculicide treatment applied to the hair, meticulous nit‑combing, and laundering of contaminated clothing and linens at high temperatures.

Lice: where do they come from and how to remove them? - in detail

Head lice (Pediculus humanus capitis) are wingless insects that live on the scalp, feeding on blood several times a day. Adult females lay 6‑10 eggs (nits) on hair shafts close to the scalp, where temperature supports embryonic development. Eggs hatch in 7‑10 days, releasing nymphs that mature into reproductive adults within another 9‑12 days. The entire life cycle completes in about three weeks, allowing rapid population growth when conditions are favorable.

Transmission occurs primarily through direct head‑to‑head contact, which is common among children in schools, daycare centers, and sports teams. Indirect transfer via shared personal items—combs, hats, hair accessories, pillows, or upholstered furniture—contributes to outbreaks, especially when infestations are untreated for several weeks.

Detection relies on visual inspection of the scalp and hair. Key indicators include:

• Live insects moving quickly across hair strands.
• Nits adhered firmly to the hair shaft within ¼ inch of the scalp; they cannot be removed easily with a fingernail.
• Itching caused by allergic reactions to saliva injected during feeding.

Effective eradication combines chemical and mechanical strategies:

1. Pediculicidal products

   • Permethrin 1 % lotion applied to dry hair, left for 10 minutes, then rinsed.
   • Pyrethrin‑based shampoos with piperonyl‑butoxide, following manufacturer’s timing guidelines.
   • Dimethicone lotion, a silicone‑based agent that suffocates lice without neurotoxic effects.

2. Manual removal

   • Fine‑toothed nit comb used on wet, conditioned hair after chemical treatment.
   • Systematic sectioning of hair, combing from scalp outward, repeating every 2‑3 days for two weeks to capture newly hatched nymphs.

3. Environmental control

   • Wash clothing, bedding, and towels used within the previous 48 hours in hot water (≥ 60 °C) and dry on high heat.
   • Seal non‑washable items in sealed plastic bags for two weeks to starve surviving lice.
   • Vacuum carpets, upholstery, and car seats to remove stray nits.

Re‑treatment after 7‑10 days eliminates any lice that survived the first application and hatches any remaining eggs. Follow‑up inspections at day 14 and day 21 confirm successful clearance. Persistent infestations may require prescription‑strength agents such as malathion or ivermectin, administered under medical supervision.

Prevention focuses on minimizing head contact and maintaining hygiene practices:

• Encourage children to keep hair pulled back during group activities.
• Discourage sharing of hats, scarves, hairbrushes, and headphones.
• Conduct regular scalp checks, especially after known exposure events.

Adhering to this protocol eliminates infestations efficiently and reduces the likelihood of recurrence.