What is the purpose of a patch test before applying hair color?

The purpose of a patch test before applying hair color is to identify any allergies to the color. This is crucial because hair dye contains various chemicals that may cause allergic reactions in some individuals. Conducting a patch test allows the stylist to apply a small amount of the hair color formula on the client's skin, usually behind the ear or on the inside of the elbow, and wait for a specified period to observe any adverse reactions. If redness, itching, or swelling occurs, it indicates that the client may be allergic to one or more ingredients in the dye, and alternative formulations or colors should be considered to prevent potential harm. This practice is a critical safety measure in cosmetology to ensure the client's well-being during hair coloring procedures.