Epidermolysis bullosa

Synonym(s)

None

Epidermolysis bullosa. Bullae, erosions, and scarring of the hands

Definition

Group of inherited disorders characterized by blister formation in response to mechanical trauma

Pathogenesis

Epidermolysis bullosa simplex: associated with mutations of the genes coding for keratins 5 and 14; level of skin separation at the mid basal cell associated with variable intermediate filament clumping Junctional epidermolysis bullosa: mutations in genes coding for laminin 5 subu-

nits (03 chain, laminin P3 chain, laminin 72 chain), collagen XVII (BP180), a6 integrin, and P4 integrin

Dystrophic epidermolysis bullosa: mutations of the gene coding for type VII collagen (COL7A1); anchoring fibrils affected; degree of involvement ranging from subtle changes to complete absence

Clinical manifestation

Epidermolysis bullosa simplex:

• Weber-Cockayne variant: most common form; blisters usually precipitated by traumatic event; most frequently occurring on the palms and soles, often with hyperhidro-sis

• Severe variant: generalized onset of blisters occurring at or shortly after birth; hands, feet, and extremities most common sites of involvement

• Koebner variant: sometimes has palmo-plantar hyperkeratosis and erosions

• Dowling-Meara variant: involves oral mucosa with grouped herpetiform blisters. Junctional epidermolysis bullosa:

• Letalis (Herlitz) variant: generalized blistering at birth; orificial erosions around the mouth, eyes, and nares; often accompanied by significant hypertrophic granulation tissue; involvement of the corneal, conjuncti-val, tracheobronchial, oral, pharyngeal, esophageal, rectal, and genitourinary mucosal surfaces; internal complications: hoarse cry, cough, and other respiratory difficulties; poor prognosis

• Nonlethal junctional variant (mitis form): usually survives infancy; generalized blistering; improves with age; scalp, nail, and tooth abnormalities; periorificial erosions and hypertrophic granulation tissue; mucous membranes erosions, resulting in strictures.

Dystrophic epidermolysis bullosa:

• Dominantly inherited variant; onset of disease usually at birth or during infancy; generalized blistering is common presentation; evolution to localized blistering with age

Epidermolysis bullosa acquisita 213

• Cockayne-Touraine variant: acral distribution and minimal oral or tooth involvement

• Pasini variant: more extensive blistering, scarlike papules on the trunk (albopapu-loid lesions); involvement of the oral mucosa and teeth; dystrophic or absent nails common

• Mitis variant: involves acral areas and nails with little mucosal involvement; clinical manifestations similar to the domi-nantly inherited forms

• Severe recessive variant (Hallopeau-Sie-mens): generalized blistering at birth; subsequent extensive dystrophic scarring, most prominent on the acral surfaces, sometimes resulting in pseudosyndactyly (mitten-hand deformity) of the hands and feet; flexion contractures of the extremities increasingly common with age; dystrophy of nails and teeth; involvement of internal mucosa sometimes resulting in esophageal strictures and webs, urethral and anal stenosis, phimosis, and corneal scarring; intestinal malabsorption leading to a mixed anemia resulting from a lack of iron absorption and failure to thrive; significant risk of developing aggressive squamous cell carcinomas in areas of chronic erosions

Differential diagnosis

Linear IgA bullous disease; bullous pemphigoid; epidermolysis bullosa acquisita; friction blisters; pemphigus vulgaris; burn

Therapy

Avoidance of frictional trauma*; careful attention to skin and dental hygiene*; severe disease: soft diet to prevent esopha-geal trauma and blistering; skin equivalent dressings to promote epithelialization

References

Fine JD, Eady RA, Bauer EA, Briggaman RA, Bruckner-Tuderman L, et al. (2000) Revised classification system for inherited epidermoly-sis bullosa: report of the Second International Consensus Meeting on diagnosis and classification of epidermolysis bullosa. Journal of the American Academy of Dermatology 42(6):1051-1066

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