The red flag warning every colourist needs to be aware of this summer

Discussing black henna tattoos might not be a priority when clients talk about their holidays, but those who dye their hair after getting a black henna tattoo are at a higher risk of allergic reactions.

Black henna is illegal in the UK because it contains p-Phenylenediamine (PPD), a chemical also found in dark hair dyes. While PPD is legal in hair dye at regulated levels, black henna often contains dangerously high amounts.

Consultant toxicologist David Basketter explains, “In the UK, we follow EU legislation that limits PPD concentration in hair colour to 2%. Our levels are safe and approved.” However, black henna tattoos, often applied on the street or beach, can contain excessive PPD levels, posing significant risks.

“The higher the concentration, the greater the risk,” says David. “Hairdressers know that over-exposure to PPD can cause allergic reactions. Most people with black henna tattoos are unaware of the PPD levels they’ve encountered.”

Reactions can occur immediately or years later, making the link less obvious. “Black henna tattoos are designed to last weeks or months, but a client might not react until years later when colouring their hair,” David adds.

To avoid severe reactions, clients should do a patch test before dyeing their hair. One solution is Colourstart professional allergy screening, licensed by the MHRA, which is the first clinically proven test for hair colour allergy. It tests against PPD and can be used with all colour brands, making it the perfect way to ensure your colour business runs smoothly no matter what the season.

For further information on Colourstart email hello@colourstart.com, visit Colourstart.com or call 0330 3905888.