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.