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  Disease summary:

  
  
  
  
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    Inherited epidermolysis bullosa (EB) is a heterogenous group of genodermatoses characterized by blisters and erosions after minimal trauma. There are four main types of EB, namely epidermolysis bullosa simplex (EBS), junctional epidermolysis bullosa (JEB), dystrophic epidermolysis bullosa (DEB), and mixed Kindler syndrome. Diagnosis is made by a combination of electron microscopy (EM) and immunofluorescence findings. Management consists of avoiding trauma and preventing complications. In lethal cases, supportive measures are instituted as well as providing emotional and financial support for families or carers.

  
  
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  Hereditary basis:

  
  
  
  
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    Autosomal recessive and autosomal dominant

  
  
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  Differential diagnosis:

  
  
  
  
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    Bullous pemphigoid, pemphigus vulgaris, linear IgA disease, arthropod bites, bullous lupus erythematosus, epidermolysis bullosa acquisita

Epidermolysis Bullosa Simplex

EBS is inherited in an autosomal dominant fashion with prevalence between 6 and 30 per 1 million live births. The actual prevalence may be higher than this as there are many patients who are undiagnosed. It is the most common type of EB but the least severe. It accounts for about 50% to 85% of all EB cases. The age of onset ranges between birth and the third decade of life.

In the majority of cases, fragility of the keratinocytes results in blister formation in the basal cell layer of the epidermis. It is distinguished from suprabasal EBS in which blisters form in the suprabasal levels. Most cases are due to missense mutations of keratin 14 and 5 which is important for the structural integrity of epidermal keratinocytes. Other genes implicated in EBS include plectin, plakophilin1, desmoplakin, and alpha-6 beta-4 (α6β4) integrin, see Table 110-1.

Clinical Manifestations

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  Erosions and blistering with minimal trauma or friction which usually heal without scarring, though hyperpigmentation can occur. EBS usually improves with age.

  
  
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  Complications include pain, infections, malnutrition, anemia, fluid and electrolyte imbalance, and an increased risk of skin cancer if severe EBS.

  
  
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  There are many clinical variants of EBS including localised EBS, EBS generalized (Dowling Meara), EBS generalized (non-Dowling Meara), EBS with muscular dystrophy, EBS with mottled pigmentation, and EBS with pyloric atresia, see Table 110-2.