Head Lice Treatment

Derbac M is a clinically proven topical liquid containing 0.5% malathion, an insecticide used to treat head lice (and their eggs, commonly known as nits), pubic lice (crabs), and scabies. It works by disrupting the nervous system of lice and scabies mites, preventing them from moving and breathing and ultimately killing them. Derbac M is alcohol-free, making it a particularly suitable option for people with asthma or eczema, who may react to alcohol-based treatments. It is suitable for adults and children aged 6 months and over. A short online consultation with one of our clinicians at Access Doctor is required before it can be issued.

For head lice, apply Derbac M to dry hair, making sure the scalp and all of the hair from root to tip is thoroughly covered. Allow the hair to dry naturally — do not use a hairdryer or sit near an open flame, as the liquid is flammable. Leave the treatment on for 12 hours or overnight, then wash it out using shampoo. Once the hair is wet, comb through it carefully with a fine-toothed nit comb to remove dead lice and eggs. Repeat the treatment 7 days later to kill any lice that may have hatched from eggs since the first application. All household members who are affected should be treated at the same time.

For scabies, apply Derbac M to the entire surface of the skin from the neck down, paying careful attention to areas between the fingers and toes, under the nails, and around the genitals. In children under 2, a thin film should also be applied to the scalp, face and ears, while avoiding the eyes and mouth. Leave the treatment on for 24 hours — you must not bathe or wash during this time. If you need to wash your hands during the 24-hour period, reapply the liquid to your hands immediately afterwards. Wash it off thoroughly after 24 hours and repeat the treatment 7 days later. All household members and close contacts should be treated at the same time, even if they have no symptoms.

For pubic lice, apply Derbac M to the entire skin surface, paying particular attention to hairy areas such as the pubic area, armpits, beard, and moustache. Avoid applying it to areas above the neck. Leave the treatment on for at least 1 hour — ideally overnight — then wash it off. Repeat the treatment after 7 days. All recent sexual partners and close contacts should also be treated at the same time, even if they have no visible symptoms, to prevent reinfection.

This is a very commonly asked question and the answer is important to understand. It is completely normal for the skin to remain itchy for some time after successful scabies treatment — the itching is caused by your body's reaction to the dead mites and their waste products, which takes time to settle. The itch can persist for 2 to 3 weeks after treatment, and sometimes up to 6 weeks, even when the treatment has worked. If the itch lasts longer than 3 weeks or seems to be getting worse rather than improving, speak to your GP or one of our clinicians at Access Doctor, as this may indicate treatment failure or reinfection.

Treating the infestation on the skin is only part of the process — it's equally important to treat your environment to prevent reinfestation. All clothing, towels, and bed linen should be washed at 50°C or above after the first treatment, as this temperature kills lice and scabies mites. Items that cannot be washed should be sealed in a plastic bag for at least 72 hours. Combs, brushes, and hair clips should be washed thoroughly in hot water. If you are treating head lice, vacuuming upholstered furniture and car seats is also advisable.

If you are pregnant or breastfeeding, you should speak to your GP or pharmacist before using Derbac M. It may still be recommended as the appropriate treatment for head lice or scabies during pregnancy, but this should only be done on the advice of a medical professional who can weigh up the risks and benefits for your individual circumstances. If you are breastfeeding, avoid applying Derbac M to the breast area and wash your hands thoroughly after application. Our clinicians at Access Doctor will be happy to advise you during your online consultation.