How to do a patch test for hair dye | The ultimate guide.

how to do a patch test for hair dye

You’re ready for a new do, a new you and a fabulous new colour. You might be taking the plunge with bleach, or maybe you’re topping up your roots with a hair dye you’ve never used before. All of these are reasons why you’ll need to how to do a patch test for hair dye.

We’re here with everything you need to know about patch test, how to do them and why it’s so important not to skip, even if you’ve been using hair dye for years. Read on!

How to do a patch test for hair dye

What is a patch test?

A patch test is a test you carry out to check that you’re not going to have any nasty allergic reactions to a product. It’s typically carried out 48 hours before you want to dye your hair. This gives it enough time for your skin to react if it’s going to.

Certain chemicals and ingredients in hair dye can cause adverse allergic reactions and patch test is a safe way of making sure your hair dye is not going to swell up your head and put you in hospital. (Soz to be dramatic!).

Patch tests are not just for hair dye products either. It’s wise to test for allergens if you have sensitive skin and are trying a new cosmetics, moisturisers, soap, or topical creams.

A hair dye patch test is often confused with a hair dye strand test. But a hair dye strand test is nothing to do with allergies. It’s a test that involves putting hair dye on a few strands of hair to check that the hair dye colour result is the one you really want.

Why do I need to do a patch test?

Plenty of people skip the patch test to save time or because they think the hair dye won’t affect them.

But when it comes to home hair dyeing, even if you’re used to certain brands, others may cause a reaction.

And in fact, the more you are exposed to chemicals in hair and even products like fake tan, the MORE chance you have of having a reaction. So it’s best to find out how to do a patch test for hair dye, be safe and check rather than rush into something that could have nasty results.

How to do a patch test for hair dye step-by-step.

Follow these easy steps to do your own patch test at home. It’s best to do it a good 48 hours before you plan to dye your hair. Try it in the morning so you have a whole day to watch for reactions.

Step one: Mix your hair dye.

To test the dye, you’ll have to open it and mix a small amount of the developer and the colourant as if you were going to dye your hair.

It only needs to be a pea-sized amount of each substance. Don’t mix the whole activator and dye together as it won’t last for 48 hours until you dye your hair.

TOP TIP! Hair dye is often on offer. You can buy two boxes of hair dye and use one for the test!

Step two: Apply the dye.

Using a cotton bud or Q-tip, dab a small amount of dye on a clean area of skin.

Because the hair dye is going to go on your head, the best place to put it is behind your ear on your neck. If you do have a reaction, it won’t be too obvious or unsightly.

However, some people prefer to place it on their inner arm.

Step three: Wait and watch.

Once the dye is dry, leave it on for 48 hours to do its thing.

If it starts to itch, burn or a rash, swelling or redness begins to develop, it’s safe to say your skin is not happy with this hair dye and you can wash it off.

Allergic reactions can be very serious. If your symptoms are worsening, you may need to call emergency services for help. You find out more about the types of allergic reactions you can have to hair dye on the NHS website here.

Step 4: No reaction? No problem.

If 48 hours later, your patch test results are clear. You can do a little skip for joy and crack on with your hair dyeing process! Good luck!

Watch and learn: How to do a patch test

What happens if I am allergic to hair dye?

The ingredient in hair dyes most often responsible for a reaction is para-phenylenediamine (PPD), which is used in many permanent hair dyes.

There are safe and ‘natural’ hair dyes you can try, but you will need to read the ingredients on the box very carefully to make sure they are truly PPD free.

PPD is the most common allergen, but you should visit your doctor if you have had a reaction so they can pin point the cause and make recommendations that are right for you.

No one should be deprived of colouring their hair! So play it safe and make sure you do a patch test!

Patch test Do’s

  • Do conduct the test 48 hours before you are due to dye your hair. Any time is fine but we prefer the morning so we have all day to watch and wash it off if we need to.
  • Do mix up only a small amount of hair dye for test, not the whole bottle (unless you have bought an extra box especially for the test).
  • Do apply it to the back of your ear on your neck. It is ok to apply it elsewhere to test the contact of it on your skin. But since this is hair dye, we’d opt for your head.
  • Do wash it off immediately if you are experiencing any adverse reactions.

Patch test Don’ts

  • Don’t skip the patch test! Even if you are a hair dyeing pro, you can still react badly to the chemicals. In fact, the more you have been exposed to hair dye, the more likely you are to have a reaction.
  • Don’t leave it on if you start to feel any itching, burning or swelling or if you notice a rash developing. Wash it off immediately. That hair dye is not for you!
  • Don’t just try another hair dye brand if you do have a reaction. The chances are it will contain the same ingredients you are reacting to. See your doctor to get to the root (sorry!) of the problem.