To check if a head lice treatment has been successful, customers should carry out detection combing two to three days after completing the course of treatment and again seven days later. If the treatment was unsuccessful, refer the customer to the pharmacist, who will consider:

• Do they still have live lice? Sometimes people see nits and think this means that lice are still present. Also, the customer may mistakenly think that itchiness means they have live lice
• Was the treatment used correctly? Did they apply sufficient product, follow the instructions properly and perform the second, follow-up treatment?
• Has the person been reinfected? It is important to check all household members and close friends to see if anyone else has head lice
• Could the lice be resistant? If resistance is suspected, a different treatment may be recommended.