What is Epidermolysis Bullosa?
Epidermolysis bullosa (EB) is divided into two types: hereditary (congenital) and acquired (epidermolysis bullosa acquisita).
Basic Information
- English name
- epidermolysis bullosa
- Visiting department
- dermatology
- Common locations
- Extremities and extremities
- Common causes
- Hereditary bullous epidermolysis is caused by a genetic mutation. Acquired bullous epidermolysis is associated with an abnormal antigen-antibody response in the body.
- Common symptoms
- Blisters, blood blister, and erosion appear on the skin after slight friction or collision
Causes of bullous epidermolysis
- EBS is associated with mutations in genes encoding keratin 5 and 14. JEB is associated with mutations in genes encoding laminin 5, XVII collagen (BPAG2), and DEB is associated with mutations in the gene encoding collagen (COL7A1). Due to mutations in the genes encoding structural proteins of the epidermis and basement membrane bands, these proteins are synthesized with abnormalities or structural abnormalities, resulting in the production of blisters in different anatomical locations.
- EBA patients are an autoimmune disease. The etiology is unknown, and studies have found that it is related to the production of anti- collagen antibodies and HLA-DR2 positive in the body.
Clinical manifestations of bullous epidermolysis
- The common feature of various types of bullous epidermolysis is that after the skin is slightly rubbed or bumped, blisters and blood blister appear. It occurs in the extremities and extremities of the joints of the limbs. In severe cases, it can affect any part of the body. Scars or miliary papules can form after skin lesions heal, and repetitive skin lesions at the extremities can make fingernails fall off.
- The simple type only involves the extremities and the extremities of the limbs, does not involve the mucosa, the skin lesions are the most superficial, and generally no scars are left after healing. Malnutrition can affect any part (including mucous membranes), and the condition is more serious. Skin lesions often occur after birth, and the location is deep. After the healing, obvious scars are left. Repeated blisters and scars on the extremities can make fingers and toes. Interstitial skin adhesion, phalanxes shrink to form claw-shaped hands; repeated ulceration of the oropharyngeal mucosa, crusting can cause mouth opening, difficulty swallowing, and poor prognosis. Junctional type is rare. Extensive blisters, bullae, and erosive surfaces appear immediately after birth. The prognosis is poor, and most patients die within 2 years of age.
- EBA occurs mostly in the elderly. Skin lesions occur on the sides of the fingers, feet, elbows, knees, and joints, and are vulnerable to trauma. The skin lesions are blisters, bullae, and erosions on the skin without inflammation. Atrophic scars, miliary papules can be seen, and some patients have hair, nail damage, and mucosal damage.
Bullous Epidermolysis Pathology
- Transmission electron microscopy and immunohistochemistry revealed that the blisters of EBS were located in the epidermis, the blisters of DEB were located in the dense lower layer, and the blisters of JEB were located in the transparent layer.
- Histopathological manifestations of EBA are subepidermal blisters, and the number of neutrophils in infiltrating cells in the blister is more than eosinophils. Direct immunofluorescence showed linear IgG deposition in the basement membrane. Visible C3 deposition. Antibodies to the basement membrane band (type I collagen) can be detected in the serum of some patients. Salt-cracked skin immunofluorescence showed that the fluorescent deposits were located on the dermal side. Transmission electron microscopy showed that the blister occurred below the dense plate.
Diagnosis of bullous epidermolysis
- According to family history and clinical characteristics, combined with immunohistochemistry and transmission electron microscopy can generally diagnose and type.
Differential diagnosis of bullous epidermolysis
- EB should be distinguished from bullous pemphigoid and pemphigoid.
Bullous Epidermolysis
- No specific treatments are currently available. The skin should be protected from friction and compression. Non-adhesive synthetic dressings, sterile gauze or broad-spectrum antibiotic ointments can be used to prevent infections, and supportive therapy should be strengthened. [1-2]