People often think that if a product stings, then it must be working. However — and this is particularly true for those with rosacea — this can be actually be an indicator of irritation. Some common skin irritants to be aware of include the following:a common sunscreen agent that may cause skin sensitivity and inflammation.These acid forms of vitamin C can increase skin sensitivity. Instead, choose no-sting vitamin C ingredients, such as magnesium ascorbyl phosphate.People with rosacea may find their skin easily irritated with oils containing cinnamon, clove, geranium, or peppermint.These compounds act as cleansing agents, but they're often too harsh and strip water out of the skin.