What is the purpose of a patch test?

A patch test is primarily conducted to determine if a client has an allergic reaction to a product. This precautionary measure is essential in the cosmetology field, particularly before applying hair color, chemical treatments, or certain skin products. By applying a small amount of the product to a discrete area of the skin, usually on the inside of the elbow or behind the ear, professionals can observe any adverse reactions that may occur within 24 to 48 hours. This helps ensure the safety of the client and avoids potential allergic reactions that could lead to discomfort or serious health issues.

The other options do not relate to the core purpose of a patch test. Measuring hair density involves evaluating the thickness and volume of hair, assessing the color level focuses on determining the right shade for hair dyeing, and analyzing skin texture involves examining the skin's surface characteristics. All of these assessments serve different cosmetic purposes but are unrelated to the need for allergy testing with the use of products.