How can lice be eliminated with tar soap? - briefly
Tar soap applied to the scalp creates an oily film that blocks the respiratory system of lice and their nits, leading to their death. After a 30‑minute exposure, rinse thoroughly and repeat the treatment after one week to eliminate any newly emerged insects.
How can lice be eliminated with tar soap? - in detail
Tar‑based soap constitutes a topical pediculicide that exploits the neurotoxic and occlusive properties of coal‑tar derivatives. The formulation typically contains a concentration of 5–10 % coal‑tar extract blended with a mild surfactant base, which facilitates penetration of the cuticle and delivery of active compounds to the nervous system of the parasite.
The active constituents, primarily phenolic compounds and polycyclic aromatic hydrocarbons, interfere with neurotransmission in lice, leading to rapid paralysis and death. Simultaneously, the viscous nature of the soap creates a film that suffocates nymphs and adult insects by blocking spiracular openings.
Preparation for application involves the following steps:
- Verify that the product is labeled for pediculicidal use and that the concentration complies with local regulations.
- Perform a patch test on a small skin area, leaving the soap in place for 15 minutes to assess potential irritation.
- Wash hair with a mild shampoo, rinse thoroughly, and towel‑dry until damp but not wet.
Application procedure:
- Apply a generous amount of the tar soap to the scalp, ensuring full coverage from the hair roots to the tips.
- Massage gently for 2–3 minutes to distribute the product evenly.
- Leave the soap on the hair for 30–45 minutes, avoiding contact with eyes and mucous membranes.
- Rinse with lukewarm water, followed by a regular shampoo to remove residual soap.
Post‑treatment actions include:
- Use a fine‑toothed nit comb to remove dead lice and nits, working section by section.
- Repeat the entire process after 7–10 days to eradicate any newly hatched nits that survived the initial treatment.
- Maintain regular hair washing and avoid sharing personal items such as combs, hats, or pillows.
Safety considerations:
- Do not apply to children under 2 years of age or to individuals with known sensitivity to coal‑tar derivatives.
- Discontinue use if redness, itching, or dermatitis develops; seek medical advice.
- Avoid use on broken or inflamed skin, as the occlusive effect may exacerbate irritation.
Efficacy data from controlled trials indicate a 85–95 % reduction in live lice counts after a single application, with comparable results to synthetic pediculicides when proper repeat dosing is observed. The occlusive mechanism also reduces the likelihood of resistance development, a notable advantage over neurotoxic insecticides.
In summary, tar‑based soap eliminates head lice through neurotoxic paralysis and suffocation, requires thorough application and a follow‑up treatment, and demands adherence to safety protocols to minimize adverse skin reactions.