Epidermolysis bullosa (EB) is a group of rare genetic disorders that result in extremely fragile skin. This means even minor friction or bumps can cause the skin to blister and tear. The condition is often diagnosed in infancy or early childhood, but milder forms may not be recognized until later in life. Because the skin is as delicate as a butterfly’s wings, children with the condition are sometimes called “butterfly children.” The severity of EB varies widely, from mild blistering on the hands and feet to widespread, life-threatening injuries.
Underlying Genetic Causes
The skin has two primary layers, the epidermis and dermis, which are held together by proteins in a specialized area called the basement membrane. These proteins act as anchors, giving skin its strength and resilience. In individuals with epidermolysis bullosa, these proteins are either absent or non-functional due to mutations in the genes that create them. There are at least 18 different genes whose mutations are known to cause the various forms of EB.
These genetic mutations are inherited from one or both parents. A person might inherit the condition from a single parent with EB, or from two parents who are carriers of the mutated gene but do not show symptoms themselves. The specific gene affected determines which protein is faulty, where the skin layers will separate, and how severe the blistering will be. This forms the basis for classifying the different types of the disorder.
Major Types and Symptoms
The most common form is Epidermolysis Bullosa Simplex (EBS), where blisters form in the top layer of the skin, the epidermis. Symptoms often affect the hands and feet and heal without leaving scars. In more severe cases, hyperkeratosis, a thickening of the skin, can develop on the palms and soles over time.
Junctional Epidermolysis Bullosa (JEB) is a rarer and often more severe form where blisters arise in the basement membrane zone between the epidermis and dermis. Blisters can form in the mouth, esophagus, and airway, and a hoarse cry in an infant can be a sign of scarring on the vocal cords. Complications include hair loss and abnormal nails, and severe forms can be fatal in infancy due to infections and fluid loss from extensive open sores.
Dystrophic Epidermolysis Bullosa (DEB) is caused by a flaw in the gene that produces type VII collagen, a protein that helps anchor the epidermis to the dermis. This results in blisters forming in the dermis. When these deeper blisters heal, they cause significant scarring, which can lead to the fusion of fingers and toes, loss of nails, and difficulty with hand function and walking. The scarring can also affect mucous membranes, leading to constipation and difficulty eating.
A fourth type, Kindler EB, is characterized by blistering that can occur across multiple skin layers. This type often appears in infancy and causes sensitivity to the sun, and the skin may appear thin and wrinkled.
Diagnosis Process
Diagnosis begins with a clinical examination by a dermatologist who observes the fragile skin and blistering. While symptoms are often apparent at birth, specific tests are required to identify the exact type of the disorder.
To determine where the skin is separating, a doctor will perform a skin biopsy. A small sample of skin from a new blister is taken and examined under a microscope. Techniques like immunofluorescence testing or transmission electron microscopy allow pathologists to pinpoint the level of cleavage within the skin’s layers, which helps classify the condition.
The most definitive method for diagnosis is genetic testing. A blood or saliva sample is analyzed to identify the specific gene mutation responsible for the condition. This confirms the diagnosis and the subtype of EB and provides information for genetic counseling. For families with a known history of EB, prenatal testing may be available to determine if an unborn baby has the condition.
Management and Care Strategies
There is no cure for epidermolysis bullosa, so treatment focuses on managing symptoms, preventing complications, and protecting the skin from injury. A component of daily care is wound management. This involves using specialized, non-adherent dressings to cover blisters and raw areas to prevent infection and promote healing while minimizing further skin trauma during dressing changes.
Pain management is another aspect of care, as blisters and wounds can be extremely painful. Strategies are tailored to the individual and can range from over-the-counter pain relievers to prescription medications for more severe pain. Nutritional support is also a focus, as the body requires extra calories and nutrients to heal chronic wounds. Swallowing difficulties can make eating painful, so high-calorie supplements and sometimes feeding tubes are necessary to prevent malnutrition and anemia.
Physical and occupational therapy play a part in maintaining function and mobility, especially for those with types that cause scarring and joint contractures. Therapists can help design strategies to protect the skin during movement and provide devices to help with daily tasks. Regular monitoring is necessary to watch for and manage complications, including skin infections and an increased risk of developing an aggressive form of skin cancer called squamous cell carcinoma in some types of EB.
Living with Epidermolysis Bullosa
The long-term outlook for individuals with epidermolysis bullosa depends on the specific type and its severity. People with mild forms may live relatively unrestricted lives with some precautions, while those with severe forms face significant daily challenges and a shortened life expectancy. The condition imposes a physical, emotional, social, and financial burden on patients and their families.
Daily life requires constant vigilance to prevent skin injury, along with time-consuming wound care routines. The visible nature of the condition can lead to social isolation and psychological distress. Coordinated care from a team of specialists, including dermatologists, nurses, dietitians, and therapists, is important for managing the complex medical needs. Patient support networks and advocacy groups also provide resources and a sense of community for those affected by the condition.