Dystrophic epidermolysis bullosa

Author: Jane Widdowson et al, DEBRA New Zealand, February 2016.


What is epidermolysis bullosa?

Epidermolysis bullosa (EB) is a group of inherited diseases that are characterised by blistering lesions on the skin and mucous membranes. These may occur anywhere on the body but most commonly appear at sites of friction and minor trauma such as the feet and hands. In some subtypes, blisters may also occur on internal organs, such as the oesophagus, stomach and respiratory tract, without any apparent friction.

What is dystrophic epidermolysis bullosa?

In dystrophic epidermolysis bullosa simplex (DEB), the site of blister formation is the lamina densa within the basement membrane zone and the upper dermis. It causes generalised blistering of the skin and internal mucous membranes and leads to scar formation.

Who gets dystrophic epidermolysis bullosa?

DEB is a rare inherited disease . There are two main subtypes of DEB — one is autosomal dominant and one is autosomal recessive. The latter is the more severe form.

What is the cause of dystrophic epidermolysis bullosa?

Dominant DEB is caused by heterozygous mutation in the type VII collagen gene (COL7A1; 120120) on chromosome 3p21.

RDEB is due to homozygous or compound heterozygous mutation in the gene encoding type VII collagen (COL7A1; 120120) on chromosome 3p21.

What are the clinical features of dystrophic epidermolysis bullosa?

DEB SubtypesFeatures
Dominant generalised DEB
  • Generalised blistering present at birth
  • Blistering becomes localised to hands, feet, elbow or knees as child grows older and in response to friction
  • Small white spots called milia are often present at healed but scarred sites
  • Bart syndrome: aplasia cutis, lesions in the mouth, and abnormal nails due to abnormal type 7 collagen in anchoring fibrils
  • May also get blistering of the oesophagus
Generalised severe recessive (R) DEB
Previously known as Hallopeau-Siemens; and;
Generalised intermediate RDEB (previously Non-Hallopeau-Siemens)
  • May present with severe blistering (generalised severe RDEB) or mild disease (generalised intermediate RDEB)
  • Generalised severe blistering is more common and involves large areas of skin and mucous membranes
  • Blisters heal but with scarring and deformity causing limited movement as fingers and toes may be fused together (mitten hands)
  • Complications such as infection, malnutrition and dehydration may cause death in infancy
  • Those that survive are at great risk of developing potentially dangerous squamous cell carcinoma (SCC) within chronic EB wounds. SCC look and behave differently in EB from in unaffected individuals. They are found on covered sites and grow rapidly. They present as ulcerated or keratotic nodules and plaques.
Recessive dystrophic epidermolysis bullosa

How is dystrophic epidermolysis bullosa diagnosed?

In the dominant subtypes of EB, where an informative family tree is known, it is often acceptable for a clinical diagnosis (based on the presenting signs) to be made by a specialist dermatologist.

  • Diagnostic tests are also available in some countries and include skin biopsy of a newly induced blister which undergoes immunofluorescence antigen mapping (IFM) and/or transmission electron microscopy (EM). Mutational analysis (blood testing of genes), although not currently considered the first-line diagnostic test, is also available in some countries.

Squamous cell carcinoma in DEB is diagnosed by its clinical appearance and supported by biopsy.

What is the treatment of dystrophic epidermolysis bullosa?

See treatment of epidermolysis bullosa – general.

  • Puritus (itching) may be a problem for patients with DEB — strategies such as moisturising and avoiding hot environments can help
  • In dominant DEB (DDEB), the focus is on blister prevention and management. This refers to the skin, but may also include eating soft foods to reduce oesophageal blisters
  • In severe recessive DEB (RDEB), high attention to both the skin and mucous membranes is necessary. Management of pain, pruritus, infection, scarring and deformities, malnutrition and anaemia all play a major part in the day to day treatment of RDEB
  • SCCs are treated surgically. This should be done early, as the tumours are aggressive and have often metastasised by the time of diagnosis. Amputation may be required.

What is the outcome for patients with dystrophic epidermolysis bullosa?

Life expectancy is unaffected in dominant DEB (DDEB). In recessive DEB (RDEB), life expectancy has now significantly improved due to appropriate management and interventions related to EB complications. These include the early detection and treatment of squamous cell carcinoma (SCC).

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