Major forms:Characterised loss of tissue integrity. Each major EB type has further subtypes which may differ in terms of their genetic, biological or clinical characteristics.
- Dystrophic epidermolysis bullosa (DEB): Upper dermis
- Junctional EB: Dermo-epidermal interface
- EB simplex (EBS) (M/C, least severe form): Within epidermis
- Kindler syndrome (KS): All 3 levels
Each EB subtype is known to arise from mutations within the genes encoding for several different proteins, each of which is intimately involved in the maintenance of keratinocyte structural stability or adhesion of the keratinocyte to the underlying dermis.
Hallmark cutaneous features:All EB types manifest with trauma-induced skin blistering and fragility, but the individual types vary in terms of severity and associated extracutaneous manifestations
- Milia (tiny firm white papules, resembling cysts or pustules)
- Nail dystrophy or absence
- Scarring (usually atrophic)
- Localized EBS “Weber-Cockayne disease” (M/C EB overall): Blistering on palms and soles
- Generalized EBS:
- EBS-Dowling Meara (DM): Presence of intact vesicles or small blisters in grouped or arcuate configuration
- EBS generalized other or non-Dowling-Meara generalized EBS “EBS-Koebner (EBS-K)”: Non-herpetiform blisters and erosions arising on any skin surface
Junctional EB (JEB):Enamel hypoplasia (characteristic): Manifested as localized or more extensive thimble-like pitting of some or all of the tooth surfaces
- Non-Herlitz JEB (JEB-nH) (80% JEB cases, less severe): Generalized disorder characterized by the presence of blistering, atrophic scarring, and nail dystrophy or absence
- JEB-Herlitz (JEB-H) (20% JEB cases): Exuberant granulation tissue which usually arises within the first several months to one to two years of life
- Inverse JEB (rare): Severe blistering and erosions confined to intertriginous skin sites, esophagus, and vagina
- JEB with pyloric atresia presents with generalized blistering at birth and congenital atresia of the pylorus (and rarely of other portions of the gastrointestinal tract)
- LOC syndrome is characterized by localized blistering and scarring, particularly on the face and neck, in association with upper airway disease activity and nail abnormalities
Dystrophic EB (DEB):Separated into two major types, based on the mode of transmission (autosomal dominant versus autosomal recessive)
- Dominant dystrophic EB (DDEB): Generalized blistering at birth which, with time, is associated with mila, atrophic (or less commonly, hypertrophic) scarring, and nail dystrophy.
- Recessive dystrophic EB (RDEB):
- Severe generalized RDEB “Hallopeau-Siemens RDEB” (M/severe subtype, one of the most devastating multiorgan genetically transmitted diseases of mankind): Generalized blistering at birth, progressive and oftentimes mutilating scarring of the skin, corneal blisters/scarring, profound growth retardation, multifactorial anemia, failure to thrive (less common than in JEB-H), esophageal strictures, and debilitating hand & foot deformities (“mitten deformities”; pseudosyndactyly)
- Non-Hallopeau-Siemens RDEB
- Inverse RDEB
EB is best diagnosed and subclassified by the collective findings obtained via detailed personal and family history, in concert with the results of immunofluorescence antigenic mapping, transmission electron microscopy, and in some cases, by DNA analysis.
Optimal patient management requires a multidisciplinary approach, and revolves around the protection of susceptible tissues against trauma, use of sophisticated wound care dressings, aggressive nutritional support, and early medical or surgical interventions to correct whenever possible the extracutaneous complications.