ABSTRACT
Irritant contact dermatitis is the hallmark of an irritant reaction. It has been traditionally classifi ed into an acute and chronic type. Strong irritants will induce a clinical reaction in a single application, whereas with less potent irritants the response may be delayed and subclinical, requiring repeated or prolonged application (3). However, not all irritant reactions manifest as dermatitis. Water, being an unconventional irritant, may irritate the skin in a way other than dermatitis. Fingertip dermatitis, or wear and tear dermatitis, is the best example of cumulative irritant reaction. In this condition, hands are chronically irritated by a variety of insults, especially water. The involved skin is hardened and fi ssured, but typical signs of dermatitis or infl ammation, such as erythema, swelling, or scaling are often lacking in the early stage. People who deal with wet work, such as hair dressers, hospital cleaners, cannery workers, bartenders, and hydrotherapists (4), are especially at risk (5). Sensory irritation, such as pruritus (6), pain (7), or skin tightness (8) may also occur after water exposure in susceptible patients or in normal hosts. Substance P (9) and VIP (10), respectively, have been implicated in their pathogenesis. Recently, tumor necrosis factor-alpha polymorphism was found to be responsible for this sensory irritation (11). Another water-induced condition is aquagenic urticaria (12), in which impurity and osmolarity of water may be important. Water as solvent for putative epidermal antigen has been proposed for its pathogenesis (13).
