Once again I read, with dismay, the distressing details of the suffering caused to a hairdresser’s client because a skin test was not performed prior to applying a chemical hairdressing treatment (The Sunday Times, October 16).

I have been a hairdresser for 40 years, over 20 of which I spent teaching trainee hairdressers on City and Guilds training programmes. An important aspect of the course is how to use strong chemical products such as bleach, dyes, permanent waving solution and relaxers and the considerable damage these can cause when used incorrectly or without adequate training.

It is essential that a skin test is carried out before chemical treatment, no matter how often the client has previously had the same product/treatment, as allergic reactions can occur at any time, whether it is to hair/skin preparations, laundry/toiletry products and even foodstuffs.

All reputable chemical products – for both professional and home use – recommend that a test be carried out 24 to 48 hours before use, and anyone working towards a City and Guilds qualification in hairdressing should be trained and formally assessed in performing the test before being declared fully competent in the procedure.

A disclaimer should also be signed by the client stating that the possible reactions have been described, and should they refuse the test the hairdresser cannot be held responsible for any reaction.

However, I am amazed at how few hairdressers even offer the procedure, let alone perform it. Ex­treme reactions are relatively uncommon, but the fact remains that they do happen, particularly with hair colouring products, as many still contain either paraphenylene diamines or toluene diamines, which cause most adverse reactions.

A further factor in these unnecessary reactions is that in some countries it is not mandatory to hold a recognised qualification to operate as a hairdresser, which in this day and age beggars belief.

Nor is it an ideal situation when some colleges and training academies have their students practising on dummy training heads rather than on live models, as this is an unrealistic environment where effective training and assessment cannot take place and important procedures may be ignored.

Thankfully, the young lady in question has apparently recovered and I support her advice urging people not to skip the test.