Epidermolysis bullosa simplex (EBS) is the most common form of the rare skin disorder known as epidermolysis bullosa.
Typically appearing in infancy or early childhood, EBS ranges from mild blistering typically localized to the hands and feet, to more severe and generalized blistering of skin across the body.
Causes of EBS
EBS is most commonly caused by mutations in either the KRT5 or KRT14 genes, which prevents keratin proteins from assembling into strong networks in the outer layer of the skin (the epidermis). Keratin, which also makes up hair and nails, is key for skin structure and protection. Mutations in keratin genes lead to an epidermis that’s fragile and easily damaged, blistering with friction or minor trauma.
Other genes with mutations associated with EBS are EXPH5 and TGM5.
In most cases, EBS is inherited in an autosomal dominant pattern, meaning that a single copy of the defective gene from either parent is sufficient to cause the disease.
Types and symptoms
EBS has four major subtypes:
- Localized EBS, formerly called Weber-Cockayne type, is marked by blisters typically confined to hands, feet, and areas where the skin has been rubbed or injured. This is the milder disease form, and usually begins in childhood, although it can manifest in adolescence and early adulthood.
- Generalized EBS, formerly called Köbner type, has blistering more widespread in the body. This form may involve the mucus membranes, fingernails and toenails, with increased skin thickening with age on the soles of the feet and palms of the hands. It usually is evident at birth or appears in early infancy.
- EBS with mottled pigmentation is characterized by fragile skin and easy blistering at birth or in infancy, darker patches of skin on the limbs and trunk, keratosis (thickened skin) on the palms and soles, and abnormal nail growth. The darkened patches of skin usually fade with age.
- Severe EBS, formerly Dowling-Meara type, is the most severe disease type and can be present at birth. It is characterized by widespread and severe blistering all over the body, and possibly in the linings of the mouth, gastrointestinal tract and upper airways. Hemorrhagic (bleeding) blisters and clusters of small white bumps, called milia, also occur, and progressive keratosis affects the palms and soles. Although symptoms may ease as a person ages, this form of EBS is a serious disease of infancy and childhood, and can be life-threatening.
EBS may first be suspected by a neonatal team if blistering is evident birth. A skin specialist — a dermatologist — will do an examination and possibly request tests that may require taking a skin biopsy for evaluation. Genetic analysis of causative mutations may also be conducted.
Treatment involves avoiding activities that damage a patient’s delicate skin, as well as excessive heat, and poorly fitting or coarse-textured clothing. Dressings are used to promote healing.
Special dressings and moisturizers are used to manage skin health, and to help control and prevent infections that may result from the open blisters. Topical or systemic antibiotics, or silver-impregnated dressings or gels may also be necessary to treat cases of infection.
Aluminum chloride and other medicines can be used to prevent blisters; keratolytics and other softening agents on hardened skin of the palms and soles may prevent tissue from thickening and cracking.
Last updated: July 8, 2021
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