Irritant Contact Dermatitis

Abstract

Irritant contact dermatitis is a non immunological local inflammatory skin reaction to external agents. The related skin damage can be the result of acute toxic aggression, generally linked to a single strong etiological agent, or of repeated cumulative aggression by several weaker irritants. Contact irritation is mediated by a complex pathogenic mechanism, and the same substance can induce different clinical features depending on the concentration. There are various classes of irritants, and their action on the skin varies greatly, as do the cellular and non cellular skin targets. Generally, irritant contact dermatitis is regarded as more common than allergic contact dermatitis, especially in the occupational setting. From the clinical- morphological standpoint, contact irritation can present with many highly variable pictures according to the type of irritant substance. While contact allergy is subjectively characterized by pruritus, irritation can manifest as burning, stinging, or smarting, sometimes with no objective clinical signs (subjective reactions to irritants). In general, the diagnosis of irritant contact dermatitis seems to pose less difficulties in the occupational field, where the conditions of exposure are normally under close control. The methods for use in humans to study the irritant power of a substance are the patch tests and other skin tests, and non invasive methods (evaporimetry and laser Doppler flowmetry). According to various authors, patients with irritant contact dermatitis have a poorer prognosis than those with allergic contact dermatitis. Bearing in mind the high incidence of this affliction, various prevention rules must be recognized as very important.