Experts have warned of the danger of a chemical used in black henna that could be affecting some 20 per cent of children.

A recent British Skin Foundation survey found that 20 per cent of children could be in danger of having serious reactions to black henna temporary tattoos, which is the same number of adults also putting themselves at risk, a trend which is popular at overseas holiday destinations.

Real henna is orange/brown in colour. Black henna tattoos are not based on henna, but a substance called paraphenylenediamine (PPD), which is found in hair dyes. PPD is allowed for use in hair dye, but its use for skin contact products, such as temporary tattoos, is illegal in the UK and Europe.

Shockingly, three quarters of people surveyed were not aware that black henna tattoos contain PPD and that when it’s used on the skin it can be dangerous, and three quarters were unaware that having a black henna tattoo can drastically increase the risk of allergic reaction when using a hair dye in the future.

Dr Anjali Mahto, Consultant Dermatologist and British Skin Foundation spokesperson, explained: “It’s worrying to see that the public just don’t realise the danger PPD can pose when it is used on the skin. We really want to get the message out there that so-called black henna tattoos are not safe for the skin and should be avoided at all costs. Parents, teens and even adults should stay well away from black henna tattoos this summer on holidays abroad, at festivals, funfairs or the British seaside – it’s simply not worth the risk.”