Epidermolysis bullosa (EB) is a rare group of inherited disorders that manifest as blistering or erosion of the skin, and, in some cases, the epithelial lining of other organs. EB is chronic, debilitating and potentially disfiguring, as patients with EB have painful wounds and blisters affecting a substantial percentage of their bodies that can lead to infection and scarring. There are many genetic and symptomatic variations of EB, but all forms share the common symptom of fragile skin that blisters and tears from the slightest friction or trauma.
There are approximately 20,000-30,000 people living with EB in the United States, and 300,000-400,000 worldwide.
Inherited EB encompasses more than 30 phenotypically or genotypically distinct entities, which share as a common feature mechanical fragility of epithelial lined or surfaced tissues, most notably the skin. A characteristic feature of all types of EB is the presence of recurrent blistering or erosions, which is the result of even minor friction.
There are four types of genetically inherited EB:
- Simplex (EBS)
- Dystrophic (DEB)
- Junctional (JEB)
- Kindler (an extremely rare form of EB)
These four types of EB are similar phenotypically (what physical manifestations look like), but differ genotypically (the genetic makeup) as well as by the area of the skin where there is blistering, otherwise known as “the site of ultra-structural disruption or cleavage.” There is also a rare autoimmune form of the disorder called EB Acquisita.
In the more severe forms of the disease, blistering can lead to deformities such as fusion of the fingers and toes, secondary skin infections, sepsis and even death. EB may also affect the mouth and esophagus, leading to feeding and swallowing problems. Serious complications, including squamous cell carcinoma, may occur in EB patients who survive childhood, which results in a high rate of mortality.
EBS accounts for the majority of these cases, with DEB the next most common form. JEB is less prevalent, and Kindler is the rarest of the four. These major types are defined by the precise ultra-structural level of the skin, which splits and blisters as shown in Figure 1.
No medications, products or procedures to date are clinically proven to effectively treat the underlying causes of manifestations associated with EB. Furthermore, current methods of treatment for the symptomatic skin conditions relating to EB (e.g. reduction and/or healing of blistering and skin erosions) are considered to be ineffective. Current standard of care consists solely of bandaging and bathing the open wounds to prevent infection and trying to manage patients’ pain.