So far, the role of antigen-presenting cells in atopic disorders has been underestimated. Recent observations, made in the skin of patients with atopic dermatitis and in the nasal mucosa of patients with allergic rhinitis suggest that Langerhans cells, being tissue-specific dendritic cells with potent antigen-presenting capacity, play an important role in the allergic inflammatory response. Evidence is presented that Langerhans cells even play a crucial role in directing the type of the allergic reaction mechanism.