What is the purpose of a patch test before hair coloring?

The purpose of a patch test before hair coloring is to determine if the client is allergic to the color product. This step is crucial for ensuring the safety and well-being of the client since hair color products can contain various chemicals that may cause allergic reactions in some individuals. By conducting a patch test, typically on a small area of the skin, a stylist can observe any adverse reactions, such as redness, swelling, or itching, before applying the product to the entire head. This precaution helps prevent potential health risks and ensures that the client can safely proceed with the desired hair coloring service.