Epidermolysis Bullosa (EB) is the name given to a group of hereditary diseases that causes blisters in the skin and mucous membrane (tissue lining the inner surface of the organs) in response to heat, minor trauma, rubbing or scratching.
A blister is a small pocket of fluid within the upper layers of the skin, typically caused by forceful rubbing (friction).
The disease is generally present at birth or early childhood with equal prevalence for both sexes.
The children born with such skin disease are described as "butterfly children" since the fragility of their skin is like the wings of a butterfly.
Etio-patho-genesis (Causes and Mechanisms)
Genes are the basic units of heredity in the living organisms. 10 genes are responsible for the formation of the skin in humans. Any alteration (mutation) in any of these genes may cause the formation of EB. However a mutation can occur in the egg or the sperm of the parent during formation and cause EB in the newborn.
The skin is made up of two layers:
- Epidermis: It is the outer layer
- Dermis: It is the inner layer
The area where these 2 layers meet is called basement membrane zone. The epidermis is attached to basement membrane through proteins called hemidesmosomes.
The collagen protein acts as an adhesive that sticks the two layers with each other and prevent the layers from moving independently. This collagen protein goes missing in the Epidermolysis Bullosa so the two layers separate and form blisters even with minor injury or friction.
Classification of Epidermolysis Bullosa
There are 3 main types of Epidermolysis Bullosa:
Epidermolysis Bullosa Simplex (EBS)
- It is the most common type of EB. It is present at birth or in early age of life.
- In this type there are changes in the gene responsible for production of keratin, a protein found in the skin, the hair and the nails.
- There is formation of blisters in the epidermis.
- This type occurs if any of both the parents has the disease.
Junctional Epidermolysis Bullosa (JEB)
- This type usually begins to develop after birth.
- In this type there are changes in genes responsible for formation of thread like hemidesmosomes that attaches epidermis to basement membrane.
- The epidermis separates from basement membrane and there is blister formation in the basement membrane layer.
- This disease occurs if both the parents have the disease.
Dystrophic Epidermolysis Bullosa
- This type is either present at birth or in early childhood.
- In this type there are changes in the genes that are responsible for theproduction of protein called collagen. This protein aids in attachment of epidermis with dermis.
A rare type called Epidermolysis Bullosa Acquisita (EBA) occurs when the immune system (defense system of the body) mistakenly attacks healthy tissue which leads to blister formation.
- Individuals with a family history of EB are at an increased risk of getting the disease themselves.
Presentation (Signs & Symptoms)
The symptoms of Epidermolysis Bullosa depend on its type.
EB simplex type has blisters on the palms, and on the soles due to friction. Walking even short distances is very painful and difficult.
Sometimes blisters are also present under tight clothing. These blisters can even be found inside the mouth. The nails of the toe become enlarged, curved and thick.
The first sign of inherited EB simplex is the presence of blisters at the elastic region of nappies in the child.
Junctional EB The new born child often die during infancy due to overwhelming infection (sepsis), malnutrition, dehydration, electrolyte imbalance or complications resulting from blistering in the respiratory, gastrointestinal or genitourinary tract.
Skin blistering and ulcerations occurs on the arms, the hands, the finger tips, the back of the head, the neck, the shoulders, the trunk, the buttocks, the legs and the feet and the toes.
In dystrophic EB type the blisters are larger in size and are present throughout the body. Due to involvement of soft tissues in the mouth, the child may have pain and difficulty in eating and swallowing (dysphagia). The nails are absent at birth or are incompletely formed. The teeth are also irregular with blisters around it. Dental caries (cavity) can also be present. The growth of the child is retarded. Hair loss is also seen and the child is mentally retarded. There may also be eye involvement. Sometimes there is also respiratory and Urinary Tract Infection.
As newborn child cannot not speak and express, he/she will cough and cry due to pain and discomfort.
Repeated blistering and scarring can cause deformities, such as fusing of the fingers or toes or abnormal bends in the joints (contractures). This bending of the joints in limbs causes difficulty in movements.
Sometimes due to blisters there is narrowing of the food pipe which causes difficulty in eating.
The EB can be diagnosed by a doctor by looking at the blisters and rashes on the skin. To confirm the diagnosis some tests can also be done, like:
Skin biopsy is done where a small sample of the affected skin is cut and then studied under microscope. This test helps to find out the specific layers that are separating and the type of Epidermolysis present.
Genetic testing may also be done, since it is a hereditary disease. Blood sample from both the parents is collected and sent to the laboratory for analysis.
Transmission electron microscopy: TEMs are capable of imaging at a significantly higher resolution when compared to light microscopes. This test is used in case of Epidermolysis Bullosa Aquisita, which is an autoimmune disease. Antibodies are produced by the body against its own hemidesmosomes in the affected individual. Electron microscopy helps in viewing these autoantibodies more clearly.
The treatment depends on the severity of the disease. The blisters present on the skin must be treated with topical or oral medicines.
1. Antibiotics: These may be available in the form of ointments such as Mupirocin, to be applied on the affected skin. In case of secondary fungal infection, anti fungals such as Amphotericin B, Fluconazole etc.are prescribed to be taken orally by the patient.
2. Steroids: Oral steroids like Dexamethasone or Prednisolone alleviate the difficulty in swallowing. The doctor will prescribe these steroids only for a short duration as long term steroids are not recommended in this disease.
3. Soothing gels may also be prescribed by the doctor.
Surgery like skin grafting wherein a thin section of the skin is removed from other parts of the body like the hips and the thighs and applied on the areas of erosions and exposed skin might be recommended for some patients
A surgery for widening of the food pipe may be recommended in a few patients to improve eating
Homeopathic medicines have been found to be effective in the early stages of EB.
A few preventive measures will definitely help a patient with EB, these include:
- Avoiding skin trauma and hot environment to prevent worsening of the condition.
- If feeding is impossible in child, then a tube called gastrostomy tube is placed in the stomach so the food is transferred directly to the stomach. Feeding through the pipe can be done overnight with the help of a pump.
- Following a proper healthy diet rich in proteins, vitamins to fight off infections and to improve recovery is recommended.
- The patient should consult a dentist for the treatment of irregular or missing teeth.
- Physical therapy should also be given to improve the movements restricted due to bending of the bones.
- Using a sterile syringe or eye dropper to feed infant with narrowed food pipe.
- Avoiding sun exposure.
- Healthy diet including milk, fresh juices, porridge should be given daily to the patients so that they get proper nutrition. Including broccoli in diet may also help.
- Trimming the child’s fingernails regularly.
Mild form of the disease improves with age. But if patients with severe cases are not treated timely, the condition might cause restricted body movements and skin Cancer which may even lead to death.
The common complications of the disease are:
- Epidermolysis Bullosa sometimes causes Anemia (decreased hemoglobin level) and weakness due to deficient diet.
- There can be narrowing of the esophagus due to blisters.
- Loss of function of the hands and the feet due to bending of the bones.
- Secondary infection of the exposed skin can also occur.
- There can be pain in the muscles.
- Epidermolysis Bullosa can even lead to skin Cancer if left untreated and further lead to death.
- There can be infection of the gums in the mouth.
- Redness and itching in the eyes can occur if the blisters are present in the eyes. It may even lead to blindness.
- If there is a family history of any form of Epidermolysis Bullosa, genetic counseling must be done for such couple, in order to prevent its occurrence in their offspring.
- In people with the family history of EB, people should wear padding around the elbows, knees, ankles, and buttocks to prevent mechanical trauma and thus blister formation.