What is the purpose of a patch test before a color service?

The purpose of a patch test before a color service is to identify allergic reactions. This step is crucial because it helps ensure the safety of the client. Hair color products often contain chemicals that can trigger allergic responses in some individuals. By conducting a patch test—usually by applying a small amount of the product on the skin, typically behind the ear or on the inner arm—practitioners can observe any adverse reactions like redness, itching, or swelling before using the product extensively on the client's hair. This preventive measure helps avoid potentially serious allergic reactions during the color service, ensuring a safe and positive experience for the client.