There are several definitions for sensitive skin. If you fall into this category, you may experience allergic reactions and irritations to products, plants or foods. Your skin may turn red at the drop of a hat or breakout suddenly without apparent reason. Medically, the underlying reason for sensitive skin is typically related to immune system dysfunction such as urticaria (hives), rosacea, atopic dermatitis (eczema) or allergic contact dermatitis. If you have sensitive skin, you need to pay it special attention to avoid damaging breakouts, scarring and discoloration.