Sensitive skin shows continuous hyperactivity to environmental factors and exhibits a reduced tolerance to frequent or prolonged use of cosmetics and toiletries. The skin displays signs of irritation such as erythema, desquamation or discomfort such as itching, burning and stinging. These conditions are becoming even more pronounced after exposure to dry and cold climates. Sensitivity can also increase with age. It has been reported for example that the skin gets more sensitive in women at the beginning of menopause.
Many ingredients usually included in cosmetics such as dimethyl sulfoxid, benzoic acid, salicylic acid, propylene glycol, lactic acid, sodium lauryl sulfate, sodium benzoate, cinnamic acid, sorbic acid are potential irritants. Formulations, in which a beneficial constituent is involved, can be detrimental for the skin in certain conditions. For example, a formulation containing a small molecule such as acid hydroxy acetic (AHA) with a lower pH can provoke sensations of tingling, itching or irritation when applied to sensitive, unhealthy or inflamed skin. Such reactions can be triggered by uncontrolled release of the acid, fast penetration into the skin and...