Ohio Cosmetology License Practice Exam

When should a patch test be performed?

1. Before applying any hair products

2. When using new hair color

3. To check for dry scalp

4. Before a trim

The correct answer is: When using new hair color

A patch test should be performed when using new hair color to check for allergic reactions or sensitivities that a client may have to the chemicals in the product. Hair dyes often contain various ingredients that could potentially cause skin irritation or an allergic response in some individuals. Performing a patch test prior to a full application allows the cosmetologist to ensure the client's safety and comfort, significantly reducing the risk of adverse reactions. While it is important to be cautious when applying hair products in general, not all require a patch test; the emphasis is particularly on hair color due to the nature of the chemicals involved. The other scenarios—checking for dry scalp or before a trim—do not necessitate a patch test because they do not involve the same risk of allergic reaction that comes with new hair coloring products.