Epidermolysis bullosa
Epidermolysis bullosa (EB) is a group of rare medical conditions that result in easy blistering of the skin and mucous membranes. Blisters occur with minor trauma or friction and are painful. Its severity can range from mild to fatal.[7] Inherited EB is a rare disease with a prevalence in the United States of 8.2 per million live births.[8] Those with mild cases may not develop symptoms until they start to crawl or walk. Complications may include esophageal narrowing, squamous cell skin cancer, and the need for amputations.
Epidermolysis bullosa
Butterfly children[1]
Painful skin blisters[2][3]
At birth[5]
Often lifelong[5]
Bullous pemphigoid, pemphigus vulgaris, friction blisters, insect bites[5]
Wound care, pain control, controlling infections, nutritional support[2]
Death usually occurs during early adulthood
around 1 in 500,000[5]
EB is due to a mutation in at least one of 16 different genes. Some types are autosomal dominant while others are autosomal recessive.[2] The underlying mechanism is a defect in attachment between or within the layers of the skin. Loss or diminished function of type VII collagen leads to weakness in the structural architecture of the dermal–epidermal junction (DEJ) and mucosal membranes.[9] There are four main types: epidermolysis bullosa simplex (EBS), dystrophic epidermolysis bullosa (DEB), junctional epidermolysis bullosa (JEB), and Kindler syndrome. The diagnosis is suspected based on symptoms and confirmed by skin biopsy or genetic testing.
There is no cure for the condition. Management involves wound care, pain control, controlling infections, nutritional support, and prevention and treatment of complications.[7] About half a million people are affected globally.[5] It occurs equally commonly in males and females.[10]
Pathophysiology[edit]
The human skin consists of two layers: an outermost layer called the epidermis and a layer underneath called the dermis. In individuals with healthy skin, there are protein anchors between these two layers (Dermo epidermal junction) that prevent them from moving independently from one another (shearing). In people born with EB, the two skin layers lack the protein anchors that hold them together, resulting in extremely fragile skin—even minor mechanical friction (like rubbing or pressure) or trauma will separate the layers of the skin and form blisters and painful sores.[17] EB individuals manifest unremitting skin blistering that evolves into chronic wounds, inflammation, and fibrosis.[18] People with EB have compared the sores with third-degree burns. Furthermore, as a complication of the chronic skin damage, people with EB have an increased risk of malignancies (cancers) of the skin.[19] Virtually any organ lined or covered by epithelium may be injured in inherited EB. External eye, esophagus, upper airway, and genitourinary tract are the epithelial surfaced tissues that are at particular risk.[20]
Diagnosis[edit]
EB can be diagnosed either by a skin (punch) biopsy at the edge of a wound with immunofluorescent mapping, or via blood sample and genetic testing.
Prognosis[edit]
A 2014 study classified cases into three types—EBS, JEB and DEB—and reviewed their times of death. The first two types tended to die in infancy and the last in early adulthood.[33] In a survey of 11 families affected by the disease, lack of awareness of the disease by both the public and health care providers raised concerns about the care provided.[5]
Epidemiology[edit]
An estimated 20 per million live births are diagnosed with EB,[34] and 9 per million people in the general population have the condition. Of these cases, approximately 92% are EBS, 5% are DEB, 1% are JEB, and 2% are unclassified. Carrier frequency ranges from 1 in 333 for JEB, to 1 in 450 for DEB; the carrier frequency for EBS is presumed to be much higher than JEB or DEB.
The disorder occurs in every racial and ethnic group and affects both sexes.[35][36]