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

The purpose of a patch test in hair coloring is primarily to determine if a client is allergic to the dye. Conducting a patch test involves applying a small amount of the dye to a discreet area of the skin, typically behind the ear or on the inner elbow, and observing for any allergic reactions such as redness, itching, or swelling over a 24 to 48-hour period. This precautionary measure is crucial for client safety, as hair dyes can contain chemicals that might trigger allergic responses in some individuals. Identifying potential allergies beforehand helps prevent serious skin reactions during the actual hair coloring process, ensuring a safer experience for the client.