Tattoos are a hype today and many celebrities from Hollywood's Madonna to Bollywood's Malaika Arora have flaunted them from time-to-time.
This trend of body art has grabbed even the young and hip people by storm.
However, people who are afraid of needles and pain or do not want a permanent imprinting on their skin opt for temporary henna and ink tattoo.
Pure henna is one of the oldest and safest means of tattoo or hair-color. Developing an allergic reaction to this herbal product is extremely rare.
Nevertheless, dermatologists warn that sometimes black henna tattoo and hair-dye contains Paraphenylendiamine (PPD), which may cause irritation and hyper-sensitivity for a long time.
Health Canada had declared use of this chemical as dangerous.
It is believed that if the henna tattoo paste is jet black it may contain PPD. This paste has very little to almost no odor.
It is safest to take off the tattoo residue completely within an hour. Over exposure of PPD to skin may result in serious damage.