Until recently, I thought that patch tests - when a hairdresser tests a dye on a small patch of your skin, at least 48 hours before you dye your hair, in order to check for reactions - were an urban myth. I assumed they were one of those things that we should all aspire to but nobody was actually achieving, like consistently getting your five-a-day, or sticking to your recommended alcohol units (just me?). In six years of colouring my hair, visiting four different salons, I had never been offered one - and that was fine by me, because who has time to pay two trips to a salon in less than a week?
I'd never heard of anyone being allergic to hair dye, and couldn't imagine that any reaction would be serious. When the risk was weighed up against the inconvenience of the test, on balance it seemed worth it. In fact, I'm embarrassed to say, the whole concept of getting a patch test seemed a bit over-cautious and hysterical.
But in November, I read about a case in which hair dye had seemingly triggered an anaphylactic reaction. 38-year-old Julie McCabe was left with serious brain damage after suffering what appeared to be a severe allergic reaction to the chemical para-phenylenediamine (PPD), which is found in over 99% of permanent hair dyes (generally the darker the dye, the higher the concentration of PPD). McCabe had dyed her hair at home, using the same product as usual.
This came as a shock. I did a bit more digging, contacting Muriel Simmons, Executive Chairman of Allergy UK, to find out more about the risks. It turns out there's quite a range. "When skin is in direct contact with hair dye, irritation can occur," she explained. "Symptoms vary from very mild to quite severe, usually affecting the scalp, neck, forehead, ears and eyelids. Some people can also have an allergic reaction to the dye, which can affect other areas of the body causing widespread itching, urticaria (nettlerash) and general unwellness. In serious cases, it can lead to anaphylactic shock, where the face and mouth swell up and breathing can be severely affected."
Allergy UK couldn't tell me the percentage of hair colour users affected by irritation or allergic reaction, because insufficient research has been done into the area - but they did say that patch tests are "highly successful". So if no one knows what my level of risk is, why have I never been offered one?
Wondering if I was the only person in the country who hadn't been getting patch tests, I did a very unscientific survey of 16 of my friends. Of the 92 salons they'd visited between them, only 11 had offered patch tests. Most of the group (13 out of 16) weren't concerned, assuming - like me - that if patch tests were necessary, salons would be insisting on them. Comments included "I don't worry about it. I assume that a good salon means high standards", "I've never had a problem so assume I won't in the future" and "I know I'm not allergic to anything, so a test would be an inconvenience."
This feeling that a patch test is a hassle is presumably the reason why salons don't always insist on them - if you ask customers to pay two visits, while the salon down the road lets them come in without a test, you risk losing business. If my friends and I are typical of the salon-visiting population, it seems that most Brits go in, hand over our cash, and blindly trust the professionals not to put us at any risk. We also assume that if we've had our hair coloured before without any reaction, we've got the all-clear for future appointments.
Not necessarily, according to Allergy UK. "It is vitally important that a salon carries out a patch test every time," Simmons told me. "Manufacturers only need to slightly adjust the ingredients and it could cause someone to react. Equally you can use the same hair dye without it being changed and then for no reason, become sensitised and suddenly react."
On the last occasion that I visited a salon, seven weeks ago, I felt a new sensation when the colour was applied. My scalp started to sting and feel hot. When it was rinsed, the irritation reduced, and a week or so later, all symptoms had gone. But now, reluctantly, I have to broach the subject of patch tests with my hairdresser.
So here's another embarrassing admission: despite everything I now know about the risks of dyeing your hair, I'm still not sure I'd demand a patch test if I hadn't had that reaction. Is it just me? Would you insist on a patch test, or does it still seem like too much hassle?