DermNet provides Google Translate, a free machine translation service. Note that this may not provide an exact translation in all languages

Epidermolysis bullosa with congenital absence of skin

Dr Hilary Brown, General Practitioner, Newcastle Skin Check, Newcastle, NSW, Australia. DermNet Editor in Chief: Adjunct A/Prof Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand. Copy edited by Gus Mitchell. September 2019.


Epidermolysis bullosa with congenital absence of skin — codes and concepts
open

What is epidermolysis bullosa with congenital absence of skin?

Epidermolysis bullosa (EB) with congenital absence of skin was previously known as Bart syndrome. It has also been known as 'type VI aplasia cutis congenita and epidermolysis bullosa'.

EB with congenital absence of skin was originally described by Bart in 1966 after observing a large family of six generations with symmetrical congenital absence of skin on the lower legs, blistering affecting mainly acral skin and sometimes mucous membranes, and nail dystrophy [1]. In 1986, Frieden proposed a classification of aplasia cutis congenita in which conditions were classified into nine groups according to location and presence of other anomalies [2]. Bart syndrome was classified as type VI aplasia cutis congenita by its combination of a congenital localised absence of skin, epidermolysis bullosa, and nail dystrophy.

In 2014, a working group of experts in EB suggested a new classification of EB based on molecular features [3]. They suggested the substitution of eponymous names with descriptive terms and recommended Bart syndrome be known as EB with congenital absence of skin.

Who gets epidermolysis bullosa with congenital absence of skin?

EB with congenital absence of skin is rare and the exact incidence is unknown. Aplasia cutis congenita is seen in 1–2 per 10,000 births [4].

EB with congenital absence of skin can be considered a rare form of aplasia cutis congenita, but the proportion of aplasia cutis congenita which can be classified as EB with congenital absence of skin is unknown.

What causes epidermolysis bullosa with congenital absence of skin?

EB with congenital absence of skin is a familial condition with an autosomal dominant pattern of inheritance. Isolated cases have also been recognised [5].

The aetiology and pathogenesis is complex as the EB may be epidermal (simplex), junctional, or dermal (dystrophic). Bart's original family have dystrophic EB with ultrastructural changes in the anchoring fibrils. The genetic abnormality in that family has been identified in the COL7A1 gene on chromosome 3 which codes for collagen VII [6,7].

The congenital absence of skin is thought to be secondary to the skin fragility and in utero trauma, explaining the symmetrical distribution on the lower legs that may rub together, rather than a failure to form the skin [7].

What are the clinical features of epidermolysis bullosa with congenital absence of skin?

EB with congenital absence of skin is a clinical triad.

  1. Congenital absence of skin on the lower legs
  2. Any type of EB elsewhere on the body
  3. Nail changes such as the congenital absence of nails or nail dystrophy.

The areas of absent skin are usually symmetrical and bilateral typically involving the medial or dorsal surface of the distal lower limbs including the tops of the feet. They are sharply demarcated, glistening red areas of ulceration [8].

In Bart's original family, the phenotype showed some variability with not all affected members showing all features of the triad [7].

EB with congenital absence of skin may also be associated with other anomalies, such as:

  • Pyloric atresia
  • Rudimentary ear development
  • Flattened nose
  • Broad nasal root
  • Wide-set eyes [5,8].

What are the complications of epidermolysis bullosa with congenital absence of skin?

Complications of EB with congenital absence of skin include infection and haemorrhage. Hypothermia, hypoglycaemia, and disorders of fluid balance may complicate large defects [4,8]. Severe mucosal involvement has caused early death [7].

How is epidermolysis bullosa with congenital absence of skin diagnosed?

EB with congenital absence of skin is a clinical diagnosis. Histological evaluation of the skin confirms the diagnosis and categorises the EB type.

Biopsy has revealed a subepidermal blister with an inflammatory infiltrate in the dermis in some cases [8]. In Bart's original series the split in the skin is below the lamina densa on electron microscopy, indicating a dermal dystrophic EB [7]. In other cases, electron microscopy findings of separation of the dermal-epidermal junction and interruption of the basal lamina are similar to that seen in junctional EB [9]. In several cases the split has been above the basement membrane indicating the epidermal simplex type [7].

What is the differential diagnosis for epidermolysis bullosa with congenital absence of skin?

The differential diagnoses of EB with congenital absence of skin include:

  • Other forms of aplasia cutis congenita — aplasia cutis is a rare congenital anomaly characterised by an absence of skin that occurs most commonly on the scalp and cranial vault. The depth of lesions can range from superficial erosion to absence of all skin layers. There are nine subtypes of aplasia cutis congenita; EB with congenital absence of skin has been classified as type VI.
  • Other forms of EB — EB is a group of rare inherited disorders characterised by blister formation due to increased skin and mucous membrane fragility. Four major types of EB have been described according to the level of skin cleavage at the ultrastructural level. EB is further classified based on inheritance, clinical findings, and molecular defects.
  • Adams-Oliver syndrome — Adams-Oliver syndrome is a rare condition characterised by aplasia cutis congenita of the scalp with transverse defects of the limbs and mottling of the skin.

What is the treatment for epidermolysis bullosa with congenital absence of skin?

The management of EB with congenital absence of skin is usually conservative. The aim is to accelerate healing of the affected areas of skin, to prevent infection or other complications, and to reduce the risk of scarring.

Topical antibacterial ointment and wet dressings are the mainstays of treatment [8]. Prophylactic systemic antibiotics are not recommended. Occasionally surgical intervention with a skin graft or flap repair may be needed for a large defect [9].

What is the outcome for epidermolysis bullosa with congenital absence of skin?

In general, the prognosis of EB with congenital absence of skin is good. Most areas of congenital absence of skin heal within weeks or months with no long-term sequelae [7,10]. However when Bart's original family was revisited, many adults continued to develop blisters, and milia and mild scarring were noted at sites of blistering. The sites of the congenital absence of skin had healed with atrophic hairless scars [7]. The nails do not recover.

See smartphone apps to check your skin.
[Sponsored content]

 

Related information

 

References

  1. Bart BJ, Gorlin RJ, Anderson VE, et al. Congenital localized absence of skin and associated abnormalities resembling epidermolysis bullosa. A new syndrome. Arch Dermatol 1966; 93: 296–304. PubMed
  2. Frieden IJ. Aplasia cutis congenita: a clinical review and proposal for classification. J Am Acad Dermatol 1986; 14: 646–60. PubMed
  3. Fine JD, Bruckner-Tuderman L, Eady RAJ, et al. Inherited epidermolysis bullosa: Updated recommendations on diagnosis and classification. J Am Acad Dermatol 2014; 70: 1103–26. PubMed
  4. Kuvat SV, Bozkurt M. Conservative treatment of a patient with epidermolysis bullosa presenting as bart syndrome: a case report. Case Rep Med 2010; 2010: 302345. PubMed
  5. Bart BJ, Lussky RC. Bart syndrome with associated anomalies. Am J Perinatol 2005; 22: 365–9. doi: 10.1055/s-2005-871657. PubMed
  6. Christiano AM, Bart BJ, Epstein EH et al. Genetic basis of Bart's syndrome: a glycine substitution mutation in the type VII collagen gene. J Invest Dermatol 1996; 106: 1340–2. doi: 10.1111/1523-1747.ep12349293. PubMed
  7. Zelickson B, Matsumura K, Kist D, et al. Bart's syndrome: ultrastructure and genetic linkage. Arch Dermatol 1995; 131: 663–8. PubMed
  8. Kulalı F, Bas AY, Kale Y et al. Type VI Aplasia Cutis Congenita: Bart’s Syndrome. Case Rep Dermatol Med 2015; 2015: 549825. PubMed Central
  9. Kim DY, Lim HS, Lim SY. Bart Syndrome. Arch Plast Surg 2015; 42: 243–5. PubMed
  10. Alfayez Y, Alsharif S, Santli A. A case of aplasia cutis congenita type VI: Bart Syndrome. Case Rep Dermatol 2017; 9: 112–8. PubMed

On DermNet NZ

Other websites

Books about skin diseases