Bioengineering Correlates of the Sensitive Skin Syndrome: The Sensory Irritation Component

Abstract

Approximately half of the general population, when asked, answer that they have “sensitive skin” [1], but in the absence of rigorous definitional standards, that term is subject to different meanings and interpretations. In the most general sense, patients with sensitive skin are unusually susceptible to the induction of inflammatory or neurosensory symptoms by various exogenous triggers, including natural and synthetically derived chemical irritants, contact allergens, ingested foods, weather conditions, sun exposure, and incorrect skin care. A proportion of patients who report that they have sensitive skin suffer from exogenously exacerbated inflammatory dermatitis. The development of inflammatory signs may follow exacerbating exposures by minutes, as in the case of immunologic and nonimmunologic contact urticaria; after many hours, as in allergic contact dermatitis; or following longer periods of cumulative exposures or skin damage, and they may or may not be associated with unpleasant neurosensory symptoms such as itching, burning, or stinging. Another group of patients, who make up the primary focus of this chapter, have a condition designated “sensory irritation.” Best understood in terms of a neurosensory irritation model, this condition is closely related to the subjective (sensory) irritation variant of the cosmetic intolerance syndrome [2]. Beginning within several minutes after facial contact with a chemical trigger, usually a cosmetic or skin care product, these patients experience 5–10 min of intense facial discomfort, unaccompanied by any objective evidence of inflammation or other visible changes in the skin. Unable to ignore this crescendo of pain, they may frantically attempt to gain relief by washing the face. Having reached their peak, symptoms gradually fade, and they usually resolve completely within 30 min after the offending exposure.