Basic physiological characteristics were examined in the uninvolved skin of 39 patients with hand eczema and in 39 healthy controls. Susceptibility to sodium lauryl sulphate (SLS)-induced irritant dermatitis was evaluated by the application of a single 24-h SLS patch test to the upper arm. Transepidermal water loss (TEWL) was measured by an evaporimeter, skin thickness by ultrasound A-scan, blood flow by laser-Doppler flowmetry and skin colour by a chroma meter using the L*a*b* system of the Commission Internationale de l'Eclairage (CIE). No difference in basal TEWL values was found between patients and controls. A decreased skin thickness was found in those with hand eczema as compared to the controls. The hand eczema patients had significantly increased L* and decreased b*-values compared to controls, indicating a more 'fair' skin. Susceptibility to SLS was increased only in patients with acute eczema, indicating that the presence of an active eczema increases the reactivity to irritants of distant uninvolved skin.