There was also a positive correlation between the severity of allergic reactions, by Sampson's severity score, and the level of IgE‐ab to milk (rs = 0.442, p = .015) but especially between IgE‐ab to casein and Sampson's severity score (rs = 0.516, p = .004) (Figure 3B,C). Here, IGHE is linked to allergic disease.