A study examined the physiological changes, transepidermal water loss (TEWL), stratum corneum thickness and serine proteases in lesioned and nonlesioned skin of atopic dermatitis (AD) patients (n = 6), AD patients with mild-moderate eczema (n = 6) and healthy controls (n = 6). Increased serine proteases were seen in acute eczematous AD skin, especially in the deeper layers of the stratum corneum. Elevated levels of stratum corneum tryptase-like enzyme (45x), plasmin (30x), urokinase (7.1x), trypsin-like kallikreins (5.8x) and chymotrypsin-like kallikreins (3.9x) were seen compared with normal skin. These elevations were associated with impaired barrier function, irritation and decreased skin capacitance (Voegeli, R. et al. Br J Dermatol 2009, 161(1): 70).