More often than most salons do them. Here's where the line actually sits.
There is no single law that says "patch test every 6 months". What exists is a chain of liability: manufacturer instructions, your insurance policy, and negligence law. Most colour manufacturers (Wella, L'Oréal, Schwarzkopf) instruct a test 48 hours before *every* application or at minimum before the first application and after any break. Your insurer almost certainly requires you to follow manufacturer instructions — skip the test, and a reaction claim can void your cover entirely.
The practical standard most UK insurers and the NHBF accept:
- New client: patch test 48 hours before the first colour service. No exceptions, even if "they've had colour for 20 years".
- Returning client: re-test after 6+ months without colour, after any reported reaction (even mild itching), after pregnancy, after a new tattoo or henna, or whenever the manufacturer reformulates the product.
- Black henna history: treat as high risk. PPD sensitisation from holiday henna is the most common trigger for severe reactions.
The hard part isn't the test — it's remembering who was tested, when, with which product line. A reaction note scribbled on a paper card from 2024 won't protect you. Keep a dated record per client: product, batch where possible, result, and who performed it. If a client refuses the test, record the refusal and decline the service. An awkward conversation costs you one appointment; an anaphylaxis claim can cost you the business.
Every client, remembered — safely.
SAY-OS keeps each client's contraindications, allergies and history in one place, and flags them at booking — so the right call happens before they're in the chair.
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