Increased plasma eotaxin in atopic dermatitis and acute urticaria in infants and children

Background: The previously reported eotaxin overexpression in the lesional skin of atopic dermatitis (AD) led us to the assumption that circulating levels of eotaxin may be elevated too. We sought to investigate the plasma expression of eotaxin in children with skin allergy in relation to clinical activity and type of lesions. Methods: Plasma eotaxin was assayed in 78 infants and children, of whom 16 had AD, 19 had acute urticaria (AU), and 43 were healthy matched subjects. Seven children in the group of AU were resampled for plasma eotaxin after clinical remission. Results: The plasma eotaxin levels in AD (median = 158 pg/ml, mean [SD] = 168 [61] pg/ml) were significantly higher than the control values (median = 60 pg/ml, mean [SD] = 59.5 [18.5] pg/ml). Not only did patients with AU demonstrate elevated plasma eotaxin levels (median = 126 pg/ml, mean [SD] = 124 [33] pg/ml), but also a significant decline occurred on follow-up. The coexistence of angioedema with AU did not cause any further increase in plasma eotaxin expression. Plasma eotaxin levels were significantly higher in AD than in AU, probably reflecting the chronic nature of eczematous AD lesions. The plasma eotaxin levels did not correlate with serum total IgE, peripheral blood absolute eosinophil count, or age of the patients. However, there was a positive correlation between age and plasma eotaxin in the control group. Conclusions: Our findings imply that circulating levels of eotaxin increase in AD and during flares of AU, probably to serve in the recruitment and activation of eosinophils. It may also represent a biomarker of lesional activity.