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Health Risks of Henna Tattoos / Mehndi Body Painting
Henna tattoos can cause painful, even fatal complications
Temporary tattoos produced by painting the skin with a henna solution are generally considered to be a safe alternative to classical tattoos. Some parents are even happy to let their children have such body ornamentation. However, due to the use of dangerous additives, some henna tattoos can be associated with serious health risks, including severe allergic skin reactions, life-threatening systemic allergic reactions and even leukemia. In addition, even henna on its own can cause life-threatening destruction of red blood cells in people, especially children, who have a metabolic disease called glucose-6-phosphate dehydrogenase (G6PD) deficiency.
Natural henna stain
Risks of applying henna to the skin
Using henna to produce elaborate decorations on the skin, an art form that is known by the term mehndi, is a long-standing tradition in Asian and Arabian countries. Traditionally it was used for ceremonial purposes such as weddings. From the 1990s, it has become increasingly popular among Westerners, both as a service offered in the West and as a tourist attraction.
Henna used on its own stains the skin an orange to brown color. Henna powder can be mixed into a paste with water and lemon juice and various essential oils added to mask the typical smell. This paste is applied to the skin and left to dry. After about 24 hours, it is picked off to reveal the orange-brown stain underneath.
Generally, this is a safe practice, but some people may find their skin becomes irritated or they develop a rash as an allergic reaction to the essential oil. Allergy to pure henna itself is fairly rare and if it does occur tends to be mild.
Henna and glucose-6-phosphate dehydrogenase (G6PD) deficiency
People with this inherited disease have insufficient levels of G6PD, an enzyme that is needed by red blood cells to enable them to function properly. Not all borderline cases are identified, particularly if there is no known history of the disease in the family.
One of the main ingredients of henna acts as a major oxidant in red blood cells which contain insufficient G6PD to protect them. Due to this oxidative process, the blood cells are destroyed, resulting in the very rapid development of anemia, jaundice, shock and even death in some cases
The case report listed in the references section below describes four such events caused by applying henna to the whole body of a 20-day-old baby girl, and just to the palms and soles of a 2-month-old baby boy, a 3-year-old boy and a 4-year-old girl. The baby boy died six days after being painted with henna.
People of any age with G6PD deficiency should never be painted with henna, neither should infants regardless of whether or not they have been diagnosed with the disease.
Dangerous black henna
“Black henna” is used to get a contrasting color against the orange-brown of natural henna. Sometimes, it is offered on its own for an all-black design. If you see that the henna artist is using a paste that is very black and glossy rather than the non-glossy dark green, khaki, or greenish brown of natural henna paste, be warned and think twice about having it applied to your skin. It might not even contain any real henna powder at all.
Likewise, ask how long the paste needs to stay on the skin. If you are told that you do not have to keep it on the skin for more than one hour, do not go ahead. A standard mehndi design needs to be left on at least overnight for the stain to develop properly. Furthermore, if you are told the stain will remain on the skin for a long time before wearing off, be wary.
In the cases described above, it is possible that hair dye or boot polish containing a chemical called para-phenylenediamine (PPD), obtained from coal tar, has been added to the paste to provide the blackness and for more rapid development of staining. PPD is banned in some countries, but other potentially dangerous chemicals are also used for the same purpose.
Tattoo for life?
Effects of PPD can last a lifetime
PPD is a very potent inducer of contact dermatitis (skin allergy).
The reaction can start within a few hours or days after contact with PPD and varies in severity from person to person. It includes itching and peeling of the skin. More severe cases develop very painful blisters (pictures in the report by Evans and Fleming listed in "References" below). When blistering is severe, the blisters can become infected with bacteria, leading to further complications.
Permanent scarring can also result from a severe allergic reaction, sometimes with the formation of ugly, raised keloid scars. The amount of pigment in the treated areas of skin can change permanently, leaving paler regions of hypopigmentation or darker regions of hyperpigmentation.
In addition, there have been cases reported of PPD in “black henna” causing instant hypersensitivity reactions such as hives and conjunctivitis, but also potentially life-threatening anaphylaxis (rapidly developing allergic reaction that can lead to shock) and angioedema (rapid swelling of the skin, subcutaneous tissues and mucous membranes).
Worryingly, there are a number of reports of a steady increase in the admission of children to hospital emergency departments due to reactions to PPD in henna mixtures.
In some cases, there is no obvious reaction the first time someone comes into contact with PPD. However, the immune system becomes sensitized, and a serious contact dermatitis can occur after a subsequent exposure, even if this occurs years later. Instant hypersensitivity reactions are also more likely to occur in someone who has been sensitized to PPD in the past.
Sensitization to PPD can result in cross-sensitization to other substances, particularly various dyes and inks. This can result in severe contact dermatitis if the person uses hair dye, even years after having had a black henna tattoo. Reactions can also occur following use of cosmetics, sunscreens, and even when wearing clothing dyed with some fabric dyes. Asthma is thought to develop in addition in some cases.
The use of sticky transfers to outline the design, followed by application of black henna with PPD has also resulted in cross-sensitization to latex.
Emirati women have increased leukemia incidence due to mehndi
Dangers of mehndi body painting
An epidemiological study published in 2010 by a team in the United Arab Emirates came up with surprising findings. A much higher incidence of acute myeloid leukemia was seen in Emirati women than in men, and the incidence in native women was also found to be higher than that in expatriate women.
In most parts of the world, however, men are far more likely to suffer from acute myeloid leukemia than women. In looking for an explanation for this, the research team homed in on mehndi body painting. Emirati women have this done as a frequent routine, and tend to have the staining paste applied to large areas of skin on their arms and legs.
Apart from the problem of coloring agents being added to the henna, the researchers found that in many places benzene or another petroleum product was used as a solvent for the mixture. They considered this use of benzene to be a probable factor influencing the leukemia statistics.
Benzene is a known carcinogen (causes cancer) and it is particularly associated with this type of leukemia. As with many carcinogens, although risk increases with increased doses and repeated exposure, there is no lower threshold limit below which risk is non-existent. This means that even very limited, one-time exposure to benzene could be enough to trigger the cancer process in some people.
Be cautious, be safe
If you do want to experiment with temporary henna tattoos, make sure you know what ingredients are being used. Be very aware of the risks of black henna. Think very hard before letting your children be painted.
Resist the temptation have the procedure done at a street or beach stall, or while you are traveling abroad. Instead, go to a reputable salon, preferably one that you know personally or that has been recommended to you.
The consequences of henna tattoos could haunt you for many years to come.
Henna causes life threatening haemolysis in glucose-6-phosphate dehydrogenase deficiency.
Raupp P, Hassan JA, Varughese M, Kristiansson B.
Arch Dis Child. 2001 Nov;85(5):411-2.
Four cases, one fatal, of red blood cell destruction in four young children painted with henna. Full paper
Extensive information about PPD can be found in the Toxnet collection of toxicology databases. Since other names exist for this compound, it is best to search the databases using the CAS number for PPD: 106-50-3.
Allergic Contact Dermatitis from a Henna Tattoo
Colby C. Evans and John D. Fleming.
New England Journal of Medicine 2008; 359:62
A severe case of blistering occurred in a 19-year-old woman 8 days after she had a henna + PPD tattoo in Kuwait. Report with 2 pictures
Acute leukemia among the adult population of United Arab Emirates: an epidemiological study
Hassan IB, Islam SI, Alizadeh H, Kristensen J, Kambal A, Sonday S, Bernseen RM.
Leukemia Lymphoma. 2009 Jul;50(7):1138-47.
The use of benzene as a solvent for henna is suggested as a likely cause of the increased incidence of acute myeloid leukemia in Emirati women. Summary