Colorado Barbering and Cosmetology Practice Exam 2025 - Free Barbering and Cosmetology Practice Questions and Study Guide

A common symptom of an allergic reaction during a patch test is redness and swelling. This occurs as a result of the body's immune response to a substance it identifies as a foreign invader. When the skin is exposed to an allergen in the patch test, the immune system may react by increasing blood flow to the affected area, resulting in redness. Additionally, the release of inflammatory chemicals can cause fluid to leak into surrounding tissues, leading to swelling. This combination of symptoms helps to indicate that the substance tested may trigger an allergic response.

While other symptoms like dryness, flaking, and darkening of the skin can occur due to various skin conditions or reactions, they do not specifically point to an allergic reaction as clearly as redness and swelling do. Understanding these typical reactions helps in identifying potential allergens and preventing further exposure in clients.