Which of these does NOT contribute to an allergic reaction to hair products?

The reason hair texture does not contribute to an allergic reaction to hair products is that allergic reactions are primarily triggered by the body's immune response to specific substances, such as certain chemicals or ingredients used in those products. Hair texture itself is a characteristic of the hair's structure and does not influence how the immune system reacts to potentially harmful ingredients.

In contrast, a patch test is a procedure used to identify if a person is allergic to certain substances, making it a relevant factor in determining potential allergic reactions. The ingredients in hair products are critical since certain chemicals can act as allergens for individuals. Additionally, a history of previous allergic reactions can indicate an increased likelihood of future reactions, as individuals may already have sensitivities to certain compounds. Therefore, it is the presence of specific allergens in products, along with an individual’s medical history, that plays a significant role in allergic reactions, while hair texture remains unrelated to these reactions.