Contemporary Grand Challenges and Opportunities in Skin Allergies

Abstract

The skin is our largest organ and plays a major role in many physiological functions. No other organ demands so much attention and concern in both states of disease and health. It represents the first barrier to our environment and has fundamental importance for human interactions and mental health. In allergic skin diseases that affect a significant proportion of our population from childhood to advanced age, skin integrity is critically impaired. It is easy to inspect the skin and to obtain biopsies. The immune system of the skin represents a complex network of keratinocytes and immune cells, including the skin-specific antigen presenting Langerhans cells. Lessons learned from allergic skin can often be transferred to other target organs, i.e., lung, nose, and gut. Accordingly, in the last decade skin allergy developed to a thriving field. Skin allergies may start in early life, for example atopic eczema, or may occur in middle life such as urticaria, but can also develop in senescence like contact dermatitis or chronic pruritus. Some diseases are inherited such as hereditary angioedema and some are acquired by genetic alterations such as mastocytosis. Many skin allergies are long-persisting and are associated with a significant impairment of healthy related quality of life. Some skin allergies may exist only during early life such as childhood atopic dermatitis, whilst others persist for the rest of the life such as contact dermatitis. In skin allergies with periodic attacks, e.g., angioedema, the triggering factors often remain unclear. Topical treatment was used for a long time in many skin allergies, with more or less effect. Fortunately, over the past years we have considerably expanded our therapeutic armamentarium (Table 1). Moreover, additional biologic and small molecule drugs dominate pharmaceutical pipelines. This short summary aims to describe a selection of recent achievements in the field of skin allergies, to point out knowledge gaps, and to encourage scientists to perform and communicate innovative research. It should be regarded as an invitation to all scientists and clinicians to participate open access Frontiers in Allergy by proposing research topics and by submitting exciting manuscripts.