Interestingly, studies have found that dysfunction of the skin barrier not only enhances sensitisation to allergens but also leads to systemic allergic responses, such as increased IgE levels and airway hyperresponsiveness, indicating that absorption of allergens through the skin of patients with atopic dermatitis is a prerequisite for the development of other allergic conditions, such as asthma and hay fever (19). This evidence concerns the gene IGHE and asthma.