Casting Creme Gloss - patch test essential?

[NewChoos]

Have a few straggly greys and not booked into hairdresser until November so thought I could try this until then.
Is the patch test essential? have had hair dyed every few months with no reactions at the hairdressers.

Yeah, you really should. The first time at least. Sorry.

Thank you. Do you have to do a patch test each time if you are using the same product?

I think I may just have to con ask DH to look after DS Sat am so I can get to the hairdressers and tie my hair back until then.

My greys have got so much worse since having DS and he's only 7 months!

AFAIK you are supposed to do a patch test each time, even with the same product in case you have developed an an allergy since the last time - occasionally a reaction can be caused by repeated exposure.

I've wondered why hairdressers don't generally do patch tests - are the dyes different or is it just that they'd know what to do if you had a severe reaction? (extremely rare but does happen www.dailyrecord.co.uk/news/scottish-news/2011/10/13/teenager-dies-in-agony-20-minutes-after-dyeing-her-hair-86908-23485448/.)

Used to get my hair coloured at the Vidal Sasson academy (by students) & they were very strict about patch tests if you hadn't had your hair dyed within the previous six months - but I've never had another hairdresser suggest it.

(Sorry didn't mean to hijack your thread with a horror story - it really is very, very rare but so sad for the young girl above who'd dyed her hair loads of times with no problem by the sounds of things & was just terribly unlucky).

Oh no far better to be warned!
Do you just use a bit from the pack for the patch test?