Introduction:
Epidermolysis bullosa (EB) is a rare inherited skin disorder resulting in blister formation after trauma or minor injuries. It not only affects the skin but may also affect other body parts such as the mouth, esophagus, lungs, muscles, eyes, nails, and teeth. Epidermolysis bullosa is not a contagious skin disorder. The severity varies in each form, so it is classified as mild, moderate, and severe. The symptoms may begin in infancy, and in some cases, symptoms do not develop until adulthood is attained. The most common symptom is the presence of fragile skin that results in the outbreak of blisters, even in minor skin injuries. Till today there is no permanent cure for epidermolysis bullosa as it is a genetic disorder.
What Are the Types of Epidermolysis Bullosa (EB)?
Epidermolysis bullosa is classified into four major variants, and each variant differs by genetic mutations. They are:
1) Epidermolysis Bullosa Simplex:
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The most common form that presents with mild clinical symptoms.
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The top layer of the skin, called the epidermis, is affected by this type.
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Blisters are seen on the hands, feet, etc.
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The lesions may spread to the mouth and digestive tract in rare and severe cases.
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Epidermolysis bullosa simplex is further subdivided into two categories, the localized and generalized forms.
2) Junctional Epidermolysis Bullosa:
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The junctional epidermolysis bullosa is less commonly seen.
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Blister formation is seen at the junction of the epidermis and dermis.
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The blisters are mild and may improve with age.
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The common clinical presentation is hair loss and abnormal toes and fingernails.
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In addition, the mouth and digestive tract may be affected, thus interfering with food intake and digestion.
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It is fatal in infants with severe conditions.
3) Dystrophic Epidermolysis Bullosa:
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It is the scarring type of EB, and the blisters are seen to occur in the lower layers of the skin, the dermis.
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It is further subdivided into dominant and recessive types.
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In mild cases, blisters are seen on the hands, feet, and knees.
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In severe forms, the lining of the mouth and digestive tract may be affected.
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Individuals affected by the dystrophic types are highly susceptible to skin cancers.
4) Kindler Syndrome:
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It is the least common variant of epidermolysis bullosa.
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Blisters are seen with increased sensitivity to sunlight (photosensitivity).
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In this variant, all the layers of the skin are affected.
What Is the Incidence and Pattern of Inheritance of EB?
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It occurs in 20 in 1,000,000 live births.
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Mild variants are seen in 1 in 50,000 children.
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Severe forms are seen in 1 in 500,000.
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It is an inherited condition that runs in families.
Epidermolysis bullosa is a genetic condition that gets passed on from the parents to their children. Epidermolysis bullosa occurs in two forms, autosomal recessive and autosomal dominant conditions.
1) Autosomal Dominant Conditions:
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The epidermolysis bullosa simplex and the dominant type of dystrophic EB are autosomal dominant types.
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In autosomal dominant conditions, only one mutated gene may be sufficient to cause the defect.
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In autosomal dominant variants, there is a 50 % chance for the child to inherit the condition if either one of the parents has a defective gene.
2) Autosomal Recessive Condition:
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The junctional EB and the recessive type of dystrophic epidermolysis bullosa are autosomal recessive conditions.
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For an autosomal recessive condition, there should be two copies of mutated genes to cause the defect. If either of the parents has a defective gene, the odds are as follows:
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25 % chance of having a healthy baby with good genes.
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50 % chance of being carriers of the condition.
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25 % chance of having a child with two defective genes.
What Causes Epidermolysis Bullosa?
Epidermolysis bullosa is an inherited condition that is caused due to gene mutations. The gene mutations result in the formation of defective keratin proteins. The keratin proteins are responsible for maintaining the integrity and scaffolds of the skin. Any gene mutations result in abnormal scaffoldings, and blisters are seen to appear at the irregular spacings between the skin surfaces. The junctional EB is caused due to mutation in the gene that codes collagen 17 or laminin 5. Collagen 17 and laminin 5 are proteins that help in anchoring the skin and keep them intact. Dystrophic EB is caused due to gene mutations in collagen 7, which is responsible for anchoring the deeper layers of the skin.
What Are the Signs and Symptoms?
The most common clinical signs and symptoms encountered are:
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Fragile skin with blisters usually begins in infancy and is seen on the hands and feet.
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Nails are either thick or absent.
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The skin of the palms and soles appear thickened.
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Hair loss due to blister formation seen on the scalp.
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Difficulty in swallowing food (dysphagia).
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Painful and itchy skin.
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Tooth decay due to poor enamel formation.
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Anemia.
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Constipation.
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Delayed growth.
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Hoarseness of the voice while crying. It is suggestive of blister formation on the vocal cords.
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Delayed wound healing.
What Are the Other Similar Conditions?
There are a few skin conditions that appear similar to epidermolysis bullosa. They are:
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Ectodermal dysplasia.
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Staphylococcal pyoderma.
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Syphilis.
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Toxic epidermal necrolysis.
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Staphylococcal scalded skin syndrome.
What Are the Possible Complications?
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Skin blisters are vulnerable to bacterial infections and sepsis. Sepsis may sometimes progress to shock and organ failures which are life-threatening.
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Poor nutrition.
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Delayed growth.
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Digestive problems and constipation.
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Skin cancer.
How Is Pediatric Epidermolysis Bullosa Diagnosed and Prevented?
Epidermolysis bullosa is confirmed by skin biopsies and genetic testing.
1) Skin Biopsies: A small portion of the skin lesion is removed and examined under a microscope. It identifies the presence of proteins for the normal functioning of the skin.
2) Genetic Testing: A sample of blood or saliva is taken and tested for chromosomal abnormalities to detect any gene mutations, as it is a genetic disorder.
As epidermolysis bullosa is a genetic disorder, it cannot be prevented. However, there are a few ways that can prevent blister formations, such as:
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Always handle the child gently.
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Cuddle the children, and it is preferred to wear cotton or soft clothes.
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Maintain a constant room temperature and keep the environment cool as possible, as hot temperatures may aggravate the blisters and worsen the condition.
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Trim the fingernails of the child regularly. It helps to prevent scratching and causing injury to the skin.
How Is Epidermolysis Bullosa Treated?
Like any other genetic disorder, there is neither a definitive treatment nor a permanent cure for epidermolysis bullosa. Therefore, supportive therapies are recommended to improve the condition of the child.
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In the case of active blisters, bandaging the open wounds helps to prevent infections and sepsis.
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Provide healthy food with a high protein content that helps in faster healing.
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Physical therapies help to improve the functioning of hands and feet.
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Feeding tubes help in resolving feeding problems and increasing appetite.
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Breathing tubes may be required in cases of severe respiratory problems.
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Surgeries may be done to rectify the deformities of the hand, feet, toes, etc.
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Widening of the esophagus may be required as the blisters can narrow the esophagus. So surgical dilation of the esophagus may be done to enhance feeding.
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In some cases, scarring may affect normal function. Hence skin grafts may be indicated.
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Medications such as antibiotics are recommended to treat infection of the wound.
Conclusion:
Lifelong medical support may be needed for patients with epidermolysis bullosa. Psychological counseling is given to parents as it may be distressing to know about the health condition of their children and support them both physically and mentally. As there is no permanent cure, supportive therapies can help the child to lead a normal life. Children may also be given counseling to overcome their low self-esteem due to recurrent skin conditions.
