Low humidity and microtrauma.

Low-humidity dermatoses arise in the work place as a result of low water content of the air. At a relative humidity of 10% or less, the horny layer becomes rigid and brittle. The combination of low humidity, high temperature, and, frequently, rapid air movement dehydrates the outer stratum corneum. This leads to pruritus and, finally, to low-grade eczema. A roughened, scaly stratum corneum becomes more susceptible to mechanical trauma. Microtrauma from small particles can aggravate the dry scaly dermatosis. Low-humidity lesions resolve quickly with the simple expedients of routine use of moisturizers and/or raising the relative humidity.