People who use henna need to be careful to avoid the products mixed with chemicals as they may cause allergic reactions and dermatitis, cautions South Asian Regional Association of Dermatologists president and Pakistan Association of Dermatologists secretary general Dr Badar S. Dhanani. Natural mehndi that just consists of the powdered leaves of the Lawsonia plant is almost allergy free.















"Cone mehndi is used during social and festive occasions but can cause a moderate to severe allergic reaction," the doctor said. "At times, the unfortunate victim is a bride who has to go through the most precious moments of her life with painful and swollen hands." A severe form of this reaction can be huge blisters (some the size of an egg) on the areas where the mehndi was applied and less severe reactions in other areas in the form of hundreds of small, itchy and painful blisters marking out the entire mehndi design. The reaction can appear three to 12 days after application. Unfortunately, at times, this reaction can form a permanent tattoo-like design on the affected area, he said.

The most commonly mixed substance is Paraphenylendiamine (PPD) and sometimes indigo dye. It is illegal to use PPD in skin products in Western countries but locally not much care is taken as the chemical gives mehndi a stronger, more intense and long lasting colour. Both chemically modified mehndi (cone mehndi) and dried powder are available off the rack.

The other group of affected people is the men and women who use it for their hair. This can cause a reaction on the face and ears, where the chemical drains down, as the hair itself is a dead tissue. The result is a mild reaction, with the darkening or graying of the skin, or a severe reaction, with oozing and eczema.