What is a primary cause of an external effect on the skin?

• A. Genetic factors
• B. Misuse of products
• C. Allergic reactions
• D. Environmental pollutants

Answer: (B)

Misuse of products directly disrupts the skin’s outer barrier and is a common, controllable way external factors produce irritation or other skin effects. When products are used improperly—such as applying too frequently, using ingredients in too high a concentration, layering incompatible products, or not patch-testing first—the protective barrier (the outermost layer of skin) can become compromised. This leads to irritation, redness, burning, or dryness as the skin reacts to the irritants or overload of active ingredients.

Genetic factors are internal and predispose how skin responds, but they don’t represent an external action causing the effect. Allergic reactions are immune responses to specific substances that may require prior sensitization, so they’re not the everyday, direct cause of external skin effects in routine product use. Environmental pollutants are external, but their effects depend on exposure and other variables; while they can contribute, they’re not as immediately controllable or as routinely impactful as misuse of skincare products in many scenarios.