Head lice are small, wingless parasites which live on human hair and feed on blood drawn from the scalp, causing itching and sometimes infection. Infestation is most frequent in children and teens and is spread through head-to-head contact as well as through sharing hats, towels, brushes and pillows, says pharmacist, Giulia Criscuolo (click here for more).

Health experts warn that children and teens may be spreading head lice by snapping selfies with friends, particularly when there is physical contact during an outbreak.

Criscuolo says children should be cautious of head-to-head contact during back-to-school time. "Children often sit close together, sometimes touching heads when using new technology or taking group selfies. They need to be aware that this may contribute to the spread of lice, particularly during an outbreak."

She suggests the following tips to prevent head-lice this school term:

- Teach your child not to share hats, brushes, hair accessories or to bump heads with friends while using cell phones or other technology.

- If you child's hair is long, pull it back into a bun or ponytail to keep it close to the scalp.

- Examine your child's head and hair for 10 minutes every week under good lighting.

- If your child has lice, do not send them to school and alert their teachers immediately.