Sensitive skin is a common skin type, but what exactly does 'sensitive' mean? According to Allure, dermatologists say sensitive skin is more reactive to irritants than normal skin. Sensitive skin is caused by nerve endings in the top layer of skin becoming irritated. The irritation of nerve endings occurs when the skin's natural barrier is weakened or broken down by triggers. Dr. Amy B. Lewis, MD Board Certified Dermatologist It is easily irritated by the weather, or by topical products.