Parents are being warned to be careful when using head lice lotion over fears it could catch alight.

People are being told not to smoke after applying the product ot a child’s hair or let them near naked flames – even the morning after – because it could cause serious burns.

The Medicines and Healthcare products Regulatory Authority has issued an alert to pharmacists to highlight the risks to parents buying over-the-counter lotions.

In the last decade, ten people have suffered serious burns as a result of head lice products. Most of the cases involved children injured when an adult lit a cigarette near the,.

One woman with head lice was left scarred for life when she bent down to adjust a gas fire.

Eight children and adults were seriously burned after using top-selling brand Hedrin, which costs £12 per 150ml bottle.

Another two caught fire using rival brands Full Marks and Nyda.

The lotions all contain flammable liquids which could help kill off lice.

Hedrin packaging warns: “Keep hair away from source of ignition, especially naked flames and burning cigarettes.

“Treated hair can readily burn if ignited.”

The MHRA first warned of the risks in 2007 – but said accidents are still happening.

The UK market for head lice products is worth nearly £20m a year.

A spokesman for Hedrin said: “Customer safety is of utmost importance.

“Hedrin four per cent lotion carries a prominent warning to keep hair away from sources of ignition, especially naked flames and burning cigarettes.

“The rest of the Hedrin range is not associated with these issues but we do always advise keeping hair away from naked flames.”