Hairdressing 101: How to do a patch test

When it comes to hair colouring, client safety should always come first. As a hairdresser, a patch test is one of the simplest yet most essential hairdressing skills you must practice to ensure your clients have a safe and positive experience. In this guide, we’ll break down everything you need to know about hairdressing patch tests – from what they are and why they’re necessary to how to perform one step by step.

What is a hairdresser patch test?

A hairdresser patch test is a small but crucial procedure that checks for an allergic reaction to hair dye and toner ingredients. The most common reactive ingredient is paraphenylenediamine (PPD), which can cause contact dermatitis in some people. It usually presents as itchy, dry, irritated, or swollen skin. While these symptoms range from mild to severe, a patch test can help identify potential reactions and keep your clients safe.

By applying a small amount of hair dye to your client’s skin, you can determine whether they are likely to experience a reaction before you use the product. It’s a quick and simple step that can save a lot of trouble later down the line.

Why do you need to do a patch test as a hairdresser?

Performing a patch test isn’t just recommended; it’s a legal requirement when using colour or toner on your clients. Here’s why:

Client safety and wellbeing: The primary reason for a patch test is to protect your clients. Allergic reactions are unpleasant at best and life-threatening at worst. By conducting a patch test, you’re prioritising their safety and showing that their well-being is your main concern.

Maintaining the reputation of your salon: A good reputation is everything in the hairdressing world. Ensuring you prioritise your clients health and safety helps build trust and loyalty, keeping them coming back.

Insurance requirements: If a client has an allergic reaction and you haven’t conducted a patch test, your insurance may become invalid. Without proof of a patch test, your actions may be difficult to defend, leaving you vulnerable to legal and financial consequences.

When should you do a patch test?

Current guidelines state that a patch test should be conducted at least 48 hours before any colour or toning treatment. While some question whether 24 hours is enough, the 48-hour window provides a more accurate timeframe to detect potential allergic reactions.

It’s important to note that even products labelled as “natural” or “organic” are not exempt from this process. Allergic reactions can still occur, so you must always err on the side of caution.

How to do a hairdressing patch test: A step-by-step guide

Performing a patch test is straightforward. Here’s how to do it:

1. Consultation and preparation: Begin by explaining the patch test to your client. Let them know what to expect and why it’s necessary.
2. Mix the product: Mix equal parts of the colour and developer in a mixing bowl (or follow the manufacturer’s recommendation).
3. Apply the product: Using a cotton bud, apply a small amount of the mixture to the crook of the client’s elbow or behind their ear. These areas are sensitive and provide a good indication of potential reactions.
4. Wait and observe: Allow the product to sit for 30–45 minutes while the client remains with you. Look for any immediate signs of a reaction, such as redness or itching.
5. Rinse and dry: Rinse the area thoroughly and pat it dry.
6. Follow-up: Instruct the client to monitor the area for 48 hours and report any delayed reactions, such as itching, swelling, or rash development.

Practical tips

What to do when your client has a reaction

Stop the process immediately if a client shows signs of an allergic reaction during or after the patch test. Advise them to seek medical advice if symptoms persist or worsen. It’s also a good idea to document the reaction for your records.

Dealing with a client who refuses a patch test

Some clients may be reluctant to undergo a patch test. While it’s tempting to skip it to keep them happy, it’s essential to stand firm. Explain the risks and your legal obligations. If they still refuse, you may need to decline the service to protect both parties.

Keep detailed records

Maintain a log of all patch tests conducted, including the date, product used, and the client’s response. This documentation is invaluable for both your business and insurance purposes.

Educate your clients

Provide your clients with a clear guide on what to look for after the patch test. Symptoms like itching, redness, swelling, or more severe reactions like nausea should be taken seriously. Let them know what steps to take if they experience a reaction at home.

Patch Test FAQs

Can a patch test cause an allergic reaction?

Yes, a patch test aims to identify potential allergic reactions. While these are rare, some clients may experience a mild reaction during the test itself.

What if my client forgets to report back after 48 hours?

If a client doesn’t update you on the results of their patch test, follow up with them before proceeding with the service. Without this confirmation, you shouldn’t perform the hair colour treatment.

Are patch tests necessary for semi-permanent colours?

Yes, even semi-permanent hair colours can contain allergens. Always perform a patch test regardless of the type of product being used.

Do I need to patch test at every appointment?

If you’re using the same product and the client has had no reactions in the past six months, a new patch test may not be required. However, confirming with the client and checking manufacturer guidelines and your insurance policy is always good practice.

The importance of patch tests

Patch tests might seem like a small step, but they play a big role in ensuring client safety, maintaining your professional reputation, and protecting your business. Making patch tests a non-negotiable part of your hairdressing routine demonstrates your commitment to excellence and care. Follow the steps and tips outlined in this guide, and you’ll be well-equipped to always provide a safe and professional service.

​Specialist hairdresser insurance through Ripe

Patch tests are an important part of any hairdresser’s role to ensure their client is safe and happy with the end result. For that added peace of mind, you may want to consider getting hairdresser insurance.

Specialist hairdresser cover through Ripe includes public and products liability which provides up to £10m of cover protecting you against third-party claims for injury or property damage.

You can learn more about hairdresser insurance through Ripe here or click to get an online quote today.