The serum levels of eosinophil cationic protein (ECP), soluble E-selectin (sE-selectin), soluble CD14 (sCD14) and interleukin (IL)-4 are known to be elevated in patients with atopic dermatitis (AD). However, little is known of the mutual relationship between these factors. To elucidate the clinical and mutual relevance of these markers, we examined the serum levels of ECP, sE-selectin, sCD14 and IL-4 as compared with eruption scores, itch scores, total IgE and numbers of peripheral eosinophils in patients with AD (n = 43), non-atopic eczema (n = 24) and urticaria (n = 13) and in normal individuals (n = 45). In 27 patients with AD the levels of these markers were compared before and after treatment. Levels of ECP were elevated only in the patients with AD, whereas the sE-selectin levels were higher not only in AD but also in non-atopic eczema in a severity-dependent manner. The levels of both markers significantly diminished after treatment. Significant correlations existed between ECP levels and numbers of eosinophils, sE-selectin levels and itch scores, and sE-selectin levels and IgE levels. No significant changes were observed in the sCD14 and IL-4 levels. Taken together, sE-selectin and ECP are good but distinct serum markers that reflect different clinical features of AD.