There are a number of theories, this amongst them. There is also a connection to atopic dermatitis, which causes a skin barrier issue that allows proteins to pa

There are a number of theories, this amongst them. There is also a connection to atopic dermatitis, which causes a skin barrier issue that allows proteins to pass. https://www.nih.gov/news-events/news-releases/scientists-identify-unique-subtype-eczema-linked-food-allergy https://www.nih.gov/news-events/news-releases/scientists-ide...