Although categorization of types of EB in the past has been controversial and often confusing, approximately 20 phenotypes of inherited EB have presently been delineated.
Blisters form by cytolysis within the epidermis or basement membrane zone of the skin.
Mild variants have been estimated to occur as frequently as 1 in every 50,000 births. The more severe varieties are believed to occur in 1 per 500,000 births per year. Depending on the type of EB, disease severity may range from occasional mild blistering of the hand and feet to severe widespread bulla formation. This may result in nonhealing erosions, infection, scarring, and joint contracture. The healing of DEB results in dystrophic or scarring change.