From its original use by bedouins to cool themselves in the desert heat by soaking their hands and feet in its mud, henna has stained human skin for millennia. But as even as its stains faded, it left patterns on the skin that led to its more widespread use today to create decorative patterns on the skin. But henna might not have come into being as such a common cultural and decorative tool, if not for its initial medicinal defences against many diseases. One study has shown that henna extract displayed toxic effects towards a harmful ringworm fungus that affects human skin, and the antibacterial potency of henna was also confirmed in a study carried out in India.
Henna is derived from a tree, Lawsonnia inermis, that grows in hot, dry regions such as North Africa and India. People used to obtain henna by drying and then grinding the leaves and stems of the plant to obtain an extract to which many cultures would add lemon, olive oil or honey. Coffee could be added to henna to make a brown shade of hair dye, tea could be used to produce a red hair dye, and turmeric for a blonde hair colour.
When there is high demand for henna decoration, on occasions such as Eid and during national events, the cost in a salon for a full hand and feet application can set you back by as much as Dh500 (US$136). But if you can't afford to go to the salon you can buy henna extract for about Dh5-10 and apply it yourself. Self-application may actually be far healthier that a salon treatment, where the henna used may contain chemicals derived from petroleum or paints.
Henna is also thought to be a nutritious hair colourant because its extracts are natural as opposed to chemical hair dyes that contain ingredients such as ammonia. It is also thought to aid in scalp care, reducing dandruff and hair loss. In addition, it improves blood circulation and helps in the prevention of water loss from the body. But whether you apply henna for the first time at a salon or on your own, one must be cautious as sensitivity is not uncommon.
A specific type of henna, the black henna used in temporary tattoos that have become increasingly popular, especially among teenagers, may present additional risks. Although pure henna is relatively safe, combining it with other colouring agents such as para-phenylenediamine (PPD), may cause further skin sensitisation. PPD is an organic compound used in products such as hair dyes, rubber chemicals and textile dyes. It is added to henna because of its temperature stability, high strength and chemical and electrical resistance. However, these properties are often shared by known carcinogens. PPD should never be applied directly to the skin in its pure form, but even when used in temporary tattoos there have been cases of contact allergies stemming from a positive reaction, as documented in a study carried out by Gazi University in Turkey.
In all cases, the agent responsible for the allergy to the decorative markings was PPD. Although the likelihood of developing an allergic reaction to pure henna is low, tattoo reactions are going to be common until PPD is removed from the henna mixture. If you have lived in the UAE for long enough, no doubt you have witnessed an adverse reaction to henna. A reaction can occur in as little as two hours after the application of henna, with symptoms including a strong burning sensation, inflammation and, in extreme cases, a high fever. Those with sensitive skin should be particularly cautious.
Henna applications on children also present particular risks. A study carried out at the American University of Kuwait has shown that long-term use of henna on children may have the cumulative effect of prolonged lead exposure and may therefore pose a health risk. One study has even suggested a link between frequent henna use and the excessive breakdown of red blood cells leading to haemolytic anaemia.
Henna is a beauty product widely held in high regard because it is viewed as natural and for its traditional use in festive occasions. However, in many henna products, chemicals are added to increase its staining properties, which account for the increase in allergic sensitivities and exposure to chemicals that may have adverse effects long after henna fades. * The National