How long should dichlorvos be left on the head for lice? - briefly
Apply the product to the scalp and leave it for about 10 minutes before washing it off thoroughly. This duration follows the standard label instructions for effective lice treatment.
How long should dichlorvos be left on the head for lice? - in detail
Dichlorvos, sold under various brand names as a liquid concentrate, is applied to the scalp to eradicate head‑lice infestations. Manufacturer instructions and public‑health guidelines specify a contact period of 10 minutes before rinsing. This interval allows the active ingredient to penetrate the louse exoskeleton and disrupt the nervous system, leading to rapid mortality.
The procedure is as follows:
- Mix the prescribed amount of concentrate with water according to the label, typically 1 ml of dichlorvos per 100 ml of water.
- Saturate the hair, ensuring the solution reaches the skin and all strands.
- Maintain the wetness for precisely 10 minutes; a timer is advisable.
- Rinse thoroughly with warm water, then wash hair with a mild shampoo.
Exceeding the 10‑minute window does not increase efficacy and may raise the risk of skin irritation, respiratory discomfort, or systemic absorption. Symptoms of over‑exposure include burning, itching, dizziness, or nausea; medical attention is required if these appear.
Safety precautions include:
- Wearing gloves during preparation.
- Keeping the solution away from eyes, mucous membranes, and broken skin.
- Avoiding use on children under two years, pregnant or nursing individuals, and persons with known organophosphate sensitivity.
- Ensuring proper ventilation in the treatment area.
After treatment, a second application is often recommended after 7–10 days to eliminate newly hatched nits, as dichlorvos does not kill eggs. Comb hair with a fine‑toothed lice comb to remove residual nits before the follow‑up dose.
Regulatory agencies in many regions have restricted or banned over‑the‑counter sales of dichlorvos for lice due to toxicity concerns. Verify local guidelines before purchase and consider alternative treatments such as dimethicone‑based lotions, which act mechanically and present a lower health risk.
In summary, the recommended exposure time is 10 minutes, followed by thorough rinsing; longer contact offers no added benefit and increases adverse‑effect potential. Adherence to dosage, timing, and safety measures ensures effective eradication while minimizing health hazards.