Final answer:
Healthy skin is not an indication of an allergic reaction to a cosmetic product. Allergic reactions are usually marked by symptoms such as redness, swelling, and inflammation, which are considered signs of an immune response and inflammation.
Step-by-step explanation:
The indication of an allergic reaction to a cosmetic product that is NOT accurate is c) healthy skin. When someone has an allergic reaction, symptoms typically include redness, swelling, and inflammation. These are signs of an immune response and are included in the cardinal signs of inflammation. Healthy skin, on the other hand, would not be symptomatic of an allergic reaction to a cosmetic product. Allergists may use skin testing to identify allergic reactions which regularly display these signs.
Redness in the context of inflammation is typically caused by increased blood flow, which results from the dilation of local blood vessels at the site of the allergen exposure. When allergies are triggered, the immune system reacts to a harmless protein, creating symptoms such as redness, swelling, or inflammation, which are unpleasant and non-protective immune responses to the perceived threat.