IGHE and inborn error of immunity: A very elevated IgE level (1000 ≥ IgE < 10,000 kU/L) is not uncommon in patients with active eczema but is suggestive of a monogenic atopy disorder or one of the hyper-IgE immunodeficiency syndromes in which extremely high total serum IgE levels (IgE ≥ 10,000 kU/L) may be found.