What triggers can lead to allergic reactions?

Allergic reactions are typically triggered by exposure to specific stimuli, which can include allergens such as pollen, pet dander, certain foods, and various chemicals found in skincare products. When the body comes into contact with these allergens, it may mistakenly identify them as harmful invaders, leading to an immune response that results in allergy symptoms. This understanding encompasses a wide range of irritants and allergens that could provoke an allergic response in sensitized individuals.

The other options refer to environmental factors or substances that may affect skin health but do not necessarily involve the immune system's allergenic response. Sunlight exposure can lead to conditions like sunburn or skin irritation, but it isn't categorized as an allergy trigger. Fatty foods are often discussed in the context of overall skin health, but they are not recognized as a direct cause of allergic reactions. Cold temperatures can lead to skin issues, such as dryness or irritation, but they do not typically induce an allergic response. Thus, exposure to stimuli effectively captures the essence of what triggers allergies.