Kentucky Cosmetology State Practice Exam 2026 - Free Cosmetology Practice Questions and Study Guide

The function of a skin patch test is specifically designed to determine if a client is allergic to a product. This test involves applying a small amount of the product to the skin, often on the forearm, and monitoring the area for any allergic reactions such as redness, itching, or swelling over a specified period, usually 24 to 48 hours later. Identifying allergies is crucial in the cosmetology field, as it helps prevent adverse reactions that could occur during hair treatments, skin care applications, or cosmetics use, ensuring the safety and satisfaction of the client.

The other options do not align with the primary purpose of a skin patch test. Analyzing skin type focuses on understanding the characteristics of the skin — such as oily, dry, or combination — rather than detecting allergies. Determining the effectiveness of a product pertains to how well a product performs its intended function, which is separate from allergy detection. Lastly, assessing skin hydration levels involves measuring moisture levels in the skin, which does not relate directly to allergies. Thus, the skin patch test serves a unique and critical role in the realm of client safety and product application.