The Hairdressing Claims Blog


The ‘why’ and ‘how’ of patch testing
Your questions on patch testing answered

Anyone who’s ever read our blog will know it’s important to undergo patch testing before you dye your hair. But just ‘why’ is it so important and ‘how’ do you go about it?

Beginning with the ‘why’ of patch testing…

Permanent and semi-permanent hair dye contains chemicals, namely paraphenylenediamine (PPD) or toluene-2, 5-diamine sulphate (PTD). These chemicals enable the colour process to take place. While hair dye manufacturers try to formulate products using ingredients that are kind to hair and limit damage, chemicals are still present and abnormal reactions can happen.

There’s no one single reaction to hair dye chemicals. The allergy response can range from the fairly minor – contact dermatitis – to the extremely major – anaphylactic shock. Mild symptoms require you to wash your hair thoroughly whereas severe symptoms demand a call to 999 for an ambulance.

To avoid a reaction to hair dye, always carry out a patch test 48 hours before your dyeing treatment. Post-Covid, the National Hair & Beauty Federation has altered its guidelines regarding patch testing every twelve months by reducing its recommendation to every six months, as individuals have been reporting a greater number of allergic reactions. Our ‘Adverse reaction to hair dye by Covid-19 survivors’ and ‘Tighter guidance insisting on more regular patch testing’ blogs cover this subject in depth.

The advice from Hairdressing Claims, as specialists in claims against hairdressers who see hair treatment injuries all the time, is to request patch testing before every dyeing appointment.

Moving on to the ‘how’ of patch testing…

Here’s how to go about performing a patch test:

  • If having your hair dyed by your hairdresser, enquire upfront about pre-appointment tests. You’ll need to visit your salon to have dye applied to a section of skin behind your ear.
  • If dyeing your own hair, use a cotton bud to apply a little amount of colour mixture to the same place, behind your ear.
  • In both instances, leave on for 48 hours before washing off. Should you experience any signs of an allergic reaction, wash off immediately and don’t proceed with the full dye job. All being well, you shouldn’t even notice the patch test sample is there, and this ‘normal’ reaction means you’re clear to go ahead.

For at-home box dyes, the instructions will provide further guidance about patch testing. For professional dyes, always choose a reputable hairdresser (not a bad salon!) who will ask for a patch test ahead of your appointment.

Having already clarified above what to do if things go wrong, we’ll end by adding that you may also need to instruct a legal hair damage compensation expert. Our team is on hand and happy to help.

To contact us, email, call 0800 141 3682 from a landline for free, phone 0333 202 6560 from a mobile or complete our online enquiry form.

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