Why a Patch Test is Non-Negotiable

Woman with coloured hair. Image by Aveda.

As someone who experiences severe skin reactions to hair dyes, let me tell you, patch tests can save you a lot of discomfort. In some cases, they can even save your life.

I know you can’t wait to have your colour done after lockdown and a patch test just seems like a waste of time, but they are so important.

Allergies to certain dyes can develop over time, even if you’ve had the same colour done with the same product 100 times before. A patch test takes seconds, and it can be the difference between having your colour done safely and suffering a nasty reaction.

Here’s why a patch test is non-negotiable.

What happens during a patch test and how could my skin react?

Usually a little bit of dye is applied to the skin behind your ear and it should be left on for 24-48 hours to check for any sign of a reaction. If your skin shows no signs of a reaction during this time, then the dye is probably safe to use.

If you do have a reaction to a dye, it can be anything from local irritation, itching, and redness of the skin to hives and a full on serious and potentially life-threatening swelling of the face and the airways. This will require emergency medical attention.

What is the main cause of allergic reactions when using hair dye?

If your skin reacts after a patch test, the likely culprit is a chemical called PPD or to give it its scientific name, paraphenylenediamine. It sounds scary, but it’s safe to use for most people.

PPD is found in most hair dyes, and you might also see it listed as PPDA, 1,4-Benzenediamine, and Phenylenediamine base on the label.

If I have a reaction during a patch test, does that mean I have to stop colouring my hair?

No, there are alternatives that aren’t likely to provoke an allergic reaction such as henna and lead-based dyes. However, you should still patch test before using these to make sure that you don’t have a sensitivity to them too.

My advice?…

Do it the right way, ladies. I know you just want your colour done yesterday, but NEVER skip a patch test, it’s just really not worth it.

We are an Aveda Salon and our goal is to nourish and protect your hair with products that contain gentle ingredients and minimal harsh chemicals.

But even the most natural products can make the skin react (think about how it’s not recommended to use essential oils neat on the skin).

So play it safe, get your patch test booked in, and come to your appointment safe in the knowledge that your quest for gorgeous hair isn’t going to put your health at risk.



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