Bullous pemphigoid (BP) is the most common autoimmune blistering skin disease. It characteristically affects the elderly (>70 years) with an annual incidence of 5 to 35 per million. This is comparable with the incidence of eosinophilic esophagitis that we determined with approximately 14 per million. Eosinophilic esophagitis has been recognized as an emerging medical problem and, consequently, several studies with anti-IL-5-antibodies have been performed and are still ongoing. It should be noted, however, that, in contrast to eosinophilic esophagitis, the incidence of BP is dramatically increasing with an average of 17% per year. Moreover, with the increase of the proportion of the elderly in the industrialized world, the medical problems associated with BP will even be more visible in the near future. For instance, patients with BP have an increased mortality risk of 2.3. In the US, an increase in mortality of BP patients has been noticed from 1979 to 2002. Taken together, BP is a frequent disease that affects mostly the elderly.