What is Patch Test?

A patch test is a small skin test carried out before certain beauty treatments — most commonly hair colour, eyelash tinting, lash extensions and some chemical treatments — to check for an allergic reaction. A tiny amount of product is applied, usually 24 to 48 hours in advance, and the area is checked for redness, itching or swelling. Reputable salons insist on patch tests both for client safety and because treatment insurance and manufacturer guidance often require documented testing.