Epidermolysis bullosa is a rare group of inherited conditions that causes a person to develop blisters in the skin and mucosal membranes when they come into contact with heat, friction, rubbing, scratching, or minor injury.
Epidermolysis bullosa (EB) is caused by a fault, or mutation, in the keratin or collagen gene, and it affects the connective tissues.
Research has previously suggested that EB affects 19 people in every million in the United States, and it is thought that 500,000 people worldwide may be living with EB. The risk is the same, regardless of gender and ethnicity.
The skin of patients with EB is extremely fragile. Even very slight friction may cause blisters as layers of skin move independently and separate.
Severity can range from mild to life-threatening. In mild EB, the blistering is confined to hands and feet, but severe EB affects the whole body, and complications such as infection, feeding difficulties, and loss of nutrients through the skin can be fatal.
Wounds heal very slowly and there can be significant scarring, physical deformity, and disability. People with severe EB have a significantly higher risk of developing skin cancers.
There is no cure. Treatment focuses on relieving the symptoms of pain, infection risk, and complications.
Effects on the body
In people with EB, friction between the outer and inner layers of skin leads to blistering.
Normal human skin has two layers, the epidermis, which is the outer part, and the dermis, or the inner part.
Normally, there are protein anchors between the layers, made of collagen, and they prevent the two layers from shearing, or moving independently from one another.
People with EB do not have these protein anchors, so when there is any friction on the skin, the two layers rub against each other and separate, resulting in painful sores and blisters.
The blistering can also occur in the inner mucous membranes, such as the mouth and esophagus. This makes it almost impossible to eat solids.
Patients whose mucous membranes are also affected may find urinating painful.
Younger people with EB are sometimes called “butterfly children,” because their skin is said to be as fragile as the wings of a butterfly.
There are three major types of EB.
The most common type of EB is epidermolysis bullosa simplex (EBS). Around 70 percent of EB cases are of this type, in which blisters form on the outer layer of the skin.
Dystrophic epidermolysis bullosa (DEB) accounts for 20 percent of cases. Blisters form on both the outer and inner layers of skin.
Junctional epidermolysis bullosa (JEB) affects around 10 percent of EB patients. Blisters form where the outer and inner layers of skin meet.
Each type has several subtypes. So far, at least 27 different types have been identified.
Where do blisters come from?
What are blisters and where do they come from? Click here to find out more.
EB is caused by faulty genes, which may be inherited. If EB is inherited, a parent has the faulty genes and passes them onto their child.