ABU DHABI // A chemical frequently added to henna, the reddish-orange dye used to paint temporary flowing designs on women's hands and feet, may be regulated because it can cause severe allergic reactions, the Ministry of Environment and Water said. The ministry said the chemical, P-phenylenediamine (PPD), was used in hair and textile dyes, printing inks and the manufacture of black rubber, but in recent years has been added to henna mixes - especially ones known as "black henna" - to speed up the dying process and produce a deeper stain on the skin.
It can cause irritation, burning, scarring, create sensitivity to certain medicines and trigger asthma and respiratory problems if inhaled. Henna manufacturers "are adding a certain chemical [PPD] and that chemical might cause an allergic reaction on the skin. It is a dangerous chemical," Dr Sa'ad al Numairi, an adviser at the ministry, said on Tuesday. "That chemical is harmful on the skin, but at what concentration? This is the question. How much you can safely add, and at what concentration, you have to study."
The ministry was considering limiting the amount used in henna mixes and launching a campaign to raise awareness about its dangers, he said. The decision to put PPD under review comes after an independent researcher last week presented a study on PPD in henna to ministry officials. Concentrations of up to 29.5 per cent were found in the 25 samples of henna products that were analysed. The EU, which describes the chemical as an "extremely potent skin sensitiser", bans the use of PPD in products to colour the skin, eyelashes or eyebrows, and recommends a concentration of no more than six per cent in hair dye. Any products containing the chemical in Europe must carry a warning. "With the introduction of PPD to the natural henna, the public has become exposed to this chemical with unknown concentrations, putting them under the risk of developing severe allergic reactions," said Aysha al Suwaidi, a researcher who undertook the study in collaboration with the University of Sharjah. Natural henna, which is made from the plant of the same name, leaves a red-orange stain on the skin, but adding PPD creates a darker, red-black hue and products containing the chemical are often marketed as "black henna". The study found that all black henna samples tested from salons and shops in the UAE contained PPD, while a small proportion of red henna samples did as well, albeit in lower proportions. PPD is an allergen and can cause strong reactions on exposure, according to Dr Mouza al Suwaidi, a consultant dermatologist at Sheikh Khalifa Medical City. Even if someone does not have a reaction the first time they are exposed to the chemical, they can become "sensitised" to it over time and can have an adverse reaction on re-exposure. Reactions range from simple skin irritations to more serious conditions. Another particular danger is that certain vital drugs have a similar structure to the chemical, and the body may reject medication such as antibiotics and anti-diabetic drugs after exposure to PPD, she said. In rare cases, the chemical can cause life-threatening conditions such as kidney failure, or even death, in some people with a deficiency of the G6DP gene. The genetic deficiency is more common in the Gulf than other regions, said Dr Suwaidi, adding that many of those who suffer from it know they should not take certain drugs, but are unaware of the potential danger of henna to them. "The problem is that they don't realise that this chemical, which is similar in structure to the medication they can't use, is hiding in this type of henna and temporary tattoos," she said. In a recent case in Dibba, in Fujairah, a woman with the enzyme deficiency was admitted to hospital suffering from vomiting and abdominal pain after applying henna. Dr Suwaidi called for more regulation of PPD's use, and said it should be prohibited completely from use in henna products. "They just use it randomly and nobody is controlling how much they put in. I think it should be banned because it's applied directly on the skin in a very high concentration. There's a high risk," she said. She added that the number of people having adverse reactions to henna dyes had risen recently, with two visiting her clinic in the past week alone. She speculated that the increase could be caused by an increase in the popularity of black henna. A beautician at the London Ladies Salon in Sharjah said more customers were requesting the colour: "Black is popular, red henna doesn't look so good." She said she knew chemicals were added to black henna but did not know what they were. Alice Joy, the manager of Angel Beauty Salon in Bur Dubai, said she believed the black henna used at her salon did not contain henna leaves, but was a mix of hair dye and henna oil. She said she had never heard of PPD. Ms Joy said the black henna was particularly popular among Europeans and Sudanese nationals, adding that Emiratis still tended to prefer the traditional kind. Rehana Kusar, the manager of Arab Sisters Ladies Salon in Abu Dhabi, said she preferred not to use black henna because of the health risks, but would apply it if a customer requested it. At her salon red remained the most popular type, but some women asked for a mix, while two or three people a week requested black henna. She agreed that the black kind was overwhelmingly preferred by her Sudanese customers. "If someone asks for black henna I check that they don't have allergies, and I won't use it on babies," she said. Allergic reactions to natural henna are very unusual and the plant carries a number of health benefits. A study carried out in India confirmed its antibacterial potency. May al Hamly, 23, an Emirati, said she generally preferred traditional henna, especially for special occasions such as weddings or Eid, but would use black henna for small designs or tattoos, despite having once had an allergic reaction to it. "It was fine the first time I used black henna but the second time I had a small design on my wrist and it came up with a rash. It wasn't that bad, just itchy," she said. "I'd still probably use it for a small design, but not a large one." Asma Mohamed, 21, said she also preferred red henna and that one of her friends had had an allergic reaction to the black variety. "I've heard that some of the materials contained in black henna are very bad for you," said the Emirati. She said she had used it once, just to try it, but would not do so again." lmorris@thenational.ae