Sensitization patterns of cow's milk and major components in young children with atopic dermatitis

BACKGROUND Cow's milk (CM) is one of the most common food allergens in children with atopic dermatitis (AD), and the component-specific immunoglobulin E (component-IgE) measurement has recently become available. OBJECTIVE This study aimed to investigate the sensitization patterns to CM and 3 major components and their clinical values in young Korean children with AD. METHODS Cow's milk-specific IgE (CM-IgE), α-lactalbumin-specific IgE (ALA-IgE), β-lactoglobulin-specific IgE (BLG-IgE), and casein-specific IgE (Cas-IgE) levels from the sera of patients with AD were measured using the UniCAP™ system (Thermo Fisher Scientific, Sweden) and collected from January 2004 to December 2010. Patients ≥ 4 years of age were excluded from the analysis. RESULTS A total of 950 patients diagnosed with AD were ultimately enrolled in the study. Among them, 471 (49.6%) patients were sensitized to CM (CM-IgE[+], > 0.35 kU/L). Sensitization to casein (n = 349, 74.1%) was most common, followed by ALA (n = 283, 60.1%), and BLG (n = 245, 52.5%). Meanwhile, 95 patients had at least 2 follow-up tests. Eighty (84.2%) of these patients tested positive to CM, and the casein sensitization rate was the highest (n = 65, 81.3%). In addition, 479 (50.4%) patients were not sensitized to CM (CM-IgE[-], ≤ 0.35 kU/L) but 35 (7.3%) patients were sensitized to at least one component. Among them, a telephone survey was accessible in 21 cases. A total of 8 (38.1%) patients still suffered from adverse reactions after consuming milk and/or dairy foods. CONCLUSION Casein was the most commonly and persistently sensitized component in CM-IgE(+) children with AD. Measuring CM component IgE antibodies, especially Cas-IgE, is helpful for evaluating problematic allergens in young children with AD.