Ask Your Pharmacist

September 11, 2019

Every fall, I send my kids to school, and every year they bring home lice. Is there something I’m doing wrong at home? 


In the past, common misconceptions existed about head lice and where they live and how they are spread. Today, we know that catching lice is not related to household conditions (for the most part) so don’t take it personally if your child catches lice. Instead, head down to your pharmacy and find a treatment option to quickly stop the spread to other children.

Head lice (Pediculus Capitis) are wingless insects that attach to the roots of hair on your head where they lay eggs (nits) and feed on the scalp, causing itch and irritation. Lice are spread by direct contact between the hair of children and adults or by sharing things that have touched an infected head like hats, combs, headphones, helmets, pillows or bedding. Contrary to popular belief, lice can’t jump. They can survive only two or three days if they aren’t on a human head. They cannot survive in carpets or on pets. Back-to-school provides an opportunity for kids to share hats or be in close contact with other heads. That’s likely why children ages five to 12 years old commonly catch lice. Many patients ask whether using tea tree oil will prevent lice. I always respond that it has not been well studied, so not much evidence exists that it works. We also don’t have any credible research that says tea tree oil is a safe lice treatment, especially in younger children.

When checking your child’s hair, if you do see any live lice, then you will want to see your pharmacist to discuss treatment options. The most commonly used option is Permethrin 1% (NIX and Kwellada-P) because it is extremely effective and cost-effective. Resistance to Permethrin is becoming more widespread, so I won’t be surprised if this changes in the near future, but today this does not deter my recommendation as first choice. If your child has a ragweed allergy, stay away from Permethrin. Resultz (a rinse) and Nyda (a spray) are also available, proven and effective options. Neither has the risk of resistance as the reason for treatment failure, but both are more expensive. Whichever treatment you use, I recommend using a fine-tooth comb to remove all lice and eggs and repeating the treatment in one week just in case any eggs remained and hatched. Any clothing, bedding and hats that have been worn in the last week should be washed in hot water or placed in a bag for two weeks. Also, check all family members and treat only those who have lice present.

Head lice is probably more common then you think, and as our population continues to grow, it’s unlikely that will change. If you have children aged five-12 years of age and you see them scratching their scalp, check for lice. Regular checks are not a bad idea during back to school season especially. Not repeating treatment is the most common reason that lice come back and this may lead to further resistance, so I highly suggest not skipping this step, even if you can’t see any lice or nits. If you have any further questions, speak to your pharmacist.

Jared Mactavish (BSc., Pharm) is a pharmacist at Guardian Pharmacy in Hampton and St. Stephen. His opinions expressed in this newspaper are published for educational and informational purposes only, and are not intended as a diagnosis, treatment or as a substitute for professional medical advice, diagnosis or treatment. Send your questions to