The correlation between serum tryptase and severity of psoriasis and atopic dermatitis (AD) was determined in addition to the correlation between total IgE levels and AD severity. The trial population comprised 71 psoriasis patients, 61 AD patients and 62 outpatients with diseases other than psoriasis or AD. Serum tryptase levels did not correlate with disease severity in either condition, and neither did total IgE levels correlate with AD disease severity (Gerdes, S. et al. Br J Dermatol 2009, 160(4): 736).