By Sam Blanchard Senior Health Reporter For Mailonline
Published: 17:49 BST, 1 August 2019 | Updated: 17:50 BST, 1 August 2019
Allergy tests for hair dye will be available on the high street for the first time after a company got Government approval to start selling them.
The Colourstart test contains a small amount of a common hair-dying chemical and is placed on the skin to see whether someone will react to it.
If the skin reacts and becomes red or swollen it's a sign the person may be allergic to the dye.
Until now the tests were available on prescription only and used by hairdressers – but now over-16s will be able to buy them to use at home.
But selling them in shops will mean people can test themselves and avoid potentially harmful reactions which can cause pain, facial swelling and even more serious side effects or anaphylactic shock.
Riley O'Brien, 18, had a dramatic allergic reaction when she used a shop-bought hair dye and didn't test it first. She had to go to A&E because her face swelled up so much she couldn't see
The Medicines and Healthcare products Regulatory Agency (MHRA) today reclassified the patch tests as a general sale medicine, instead of prescription-only.
'The move to make the Colourstart Test more widely accessible will make it easier for people to screen for allergy to hair colourant and to avoid suffering skin reactions if they are allergic,' said the MHRA's Jan MacDonald.
The manufacturer, Trichocare, will now be able to market the patches to high street shops such as Boots and Superdrug. It's not yet clear where they will be sold.
Patches like these work by the customer placing it on their arm to test whether the chemical inside – paraphenylenediamine – is safe to use on their skin.
They have a placebo patch with no chemicals in it to place on the other arm to compare the effects.
Current testing works by the customer dabbing a small amount of the dye on their skin before using it to check whether it's safe to use.
Paraphenylenediamine, also known as PPD, is one of the most common hair dye ingredients and is found in more than two thirds of products.
A teenager was left temporarily blinded, with a dramatically swollen face and with pus-filled scabs on her hairline after having an allergic reaction to her hair dye.
Riley O'Brien, 18, decided against doing a patch test before dying her hair because she had used the same box dye before.
But the nursery worker, from Colchester, suffered an allergic reaction that left her with chemical burns, despite her regularly dying her hair for four years.
Her scalp became tight and itchy the day after her dye-disaster, and her