A 6 year old male child presented with erosion, scarring,
closure of the digits of the right foot, absent nails,
resulting in mitten appearance (fig 1). The
lesion was present since birth with healing and blistering
cycle occurring from infancy leading to progressive
pseudosyndactyly characteristic of dystrophic epidermolysis
bullosa. A few similar lesion were also seen on the other
areas of the body. There was loss of upper teeth in our
patient.
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Fig.1 Erosions, and atrophic scars on
feet. Note loss of nails of all digits,
pseudosyndactyly and mitten-like deformity of right
foot.
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A differential diagnosis of epidermolysis
bullosa and congenital Porphyrias (congenital erythropoietic
porphyria, erythropoietic protoporphyria etc), were
considered. Absence of photosensitivity, lesions on sun
exposed parts, hypertrichosis, and red/pink urine were in
favour of diagnosis of epidermolysis bullosa over porphyrias.
Based on distinctive clinical feature, a diagnosis of
dystrophic epidermolysis bullosa was made.
Dystrophic epidermolysis bullosa (DEB) is
characterised by blisters that heal with scarring and milium
formation. DEB is derived from defects of ultrastructural
entity known as anchoring fibril, which results in sublamina
densa separation. DEB can be inherited either in an
autosomal recessive or dominant fashion. There are four
primary subtypes which include dominant DEB of Cockayne-Touraine,
dominant DEB of Albopapuloid or Pasini variant, localised
recessive DEB and generalised recessive DEB. Although
generalised blistering can take place early in life,
blistering usually become localised to repetitively
traumatised areas such as knees and acral surfaces. The
areas show characteristic scarred, dystrophic appearance.
Nail dystrophy or nail loss with atrophic scarring of the
digital digits are common. The oropharynx can be severely
affected in some cases with scarring that limits the
movement of the structures. The teeth may show enamel
pitting and caries leading to loss of teeth. Mucosal
erosions of the esophagus can also be present, all these
features and caloric need for wound healing can lead to
malnutrition and growth retardation.
Pseudosyndactyly resulting from closure
of the digits in a mitten of skin is extremely common. Skin
biopsy with the dermal-epidermal basement membrane zone
visualised by electron microscopy or indirect
immunofluoroscent microscopy, will show the level of
blistering. Management includes treatment of infection and
gastrointestinal problems, eye care, supportive skin care,
and nutritional management.