Epidermolysis bullosa (EB) is an inherited connective tissue disease causing blisters in the skin and mucosal membranes, with an incidence of 1/50,000. Its severity ranges from mild to lethal. It is caused by a mutation in the keratin or collagen gene.
As a result, the skin is extremely fragile. Minor mechanical friction or trauma will separate the layers of the skin and form blisters. People with this condition have an increased risk of cancers of the skin, and many will eventually be diagnosed with it as a complication of the chronic damage done to the skin.
The skin has two layers; the outer layer is called the epidermis and the inner layer the dermis. In normal individuals, there are protein anchors, made of collagen, between the two layers that prevent them from moving independently from one another (shearing). In people born with EB, the two skin layers lack the protein anchors that hold them together, and any action that creates friction between the layers (like rubbing or pressure) will create blisters and painful sores. Sufferers of EB have compared the sores with third-degree burns.
The condition was brought to public attention in the UK through the Channel 4 documentary The Boy Whose Skin Fell Off, chronicling the life and death of Jonny Kennedy, an English man with EB.
"Butterfly Children" is a term often used to describe younger patients because the skin is said to be as fragile as a butterfly’s wings.