Skin Barrier Dysfunction and Systemic Sensitization to Allergens Through the Skin

Abstract

Most allergic, atopic and hypersensitive reactions are associated with Th2-biased immune responses and allergen-specific IgE antibodies. Pathological allergic disorders are on an alarming increase in the industrialized world. Understanding the mechanism of primary sensitization to allergens is important in elucidating the pathogenesis of these diseases and for possibly preventing their development. In this article, we review recent information supporting that epidermal allergen exposure may contribute to systemic allergic diseases and that atopy may be secondary to skin barrier dysfunction in some dermatoses. The skin is an active immunological organ, which functions as a primary defence and biosensor to the external environment. The critical permeability barrier function is mediated by the outmost layer of the epidermis, the stratum corneum. Perturbation of the stratum corneum initiates a chain of event, which activates homeostatic responses in the underlying epidermis. Repeated barrier-disruption, whether environmentally or genetically determined, may however stimulate signaling cascades that lead to inflammation and epidermal hyperplasia. Skin barrier dysfunction may also allow entry of allergens, which can lead to primary systemic sensitization. The altered epidermal microenvironment in barrier-disrupted skin appears to be particularly well suited for the induction of potent Th2-type responses with production of allergen-specific IgE. Epidermal exposure to food antigens can prevent the normal induction of oral tolerance and also lead to airway eosinophilia following inhalation. Exposure to allergens on barrier-disrupted skin may as such serve as a natural sensitization pathway for food allergy and respiratory allergic disease.

Olopatadine Hydrochloride Improves Dermatitis Score and Inhibits Scratch Behavior in NC/Nga Mice

“…6b). Recent studies revealed that exposure to allergens through barrier-disrupted skin might promote the production of allergen-specific IgE [41]. Olopatadine may decrease the antigen-specific IgE titer by improving the skin barrier function.…”

Does Sensitization to Foods in Adults Occur Always in the Gut?

“…In conclusion, contact between allergens and the immune system via the digestive tract is generally associated with the induction of tolerance whereas epidermal or respiratory exposure can prevent it [24,108]. The possibility that, at least in some cases, a story of food allergy in adults may start outside the gut cannot be ruled out.…”

Influence of Different Cosmetic Formulations on the Human Skin Barrier

“…However, the side effects that the barrier is then open for other substances, such as allergens from the environment, or that the TEWL is increased is often not considered. Strid and Strobel [13 ]pointed out that skin barrier dysfunction may also allow entry of allergens which can lead to a primary systemic sensitization. If there were only short intervals between the applications, the skin could not recover, the damage would continue and the result would be a long-term affected skin barrier.…”