What is a common indicator of a skin allergy?

A common indicator of a skin allergy is redness or rash. This reaction occurs when the skin comes into contact with an allergen, leading to inflammation and irritation. The immune system responds to the allergen by releasing histamines, which cause blood vessels to dilate and become leaky, resulting in redness, swelling, and the formation of a rash. This is a clear sign that the skin is reacting negatively to a substance, often accompanied by itching and discomfort. Recognizing this symptom is crucial for identifying potential allergens and avoiding further exposure, which is especially important in the field of cosmetology where various products may lead to allergic reactions.