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Bullous congenital ichthyosiform erythroderma (BCIE) is a keratinization disorder characterized by the presence of blisters at birth or shortly thereafter. The prevalence is estimated at between 1/300,000 and 1/200,000. Infants present with erythroderma, blisters and superficial erosions at sites of minor trauma. Hyperkeratosis usually develops later in early childhood. Yellow-brown, waxy and ridged scale builds up in skin creases, sometimes forming linear and spiny (hystrix) outgrowths. Over time, blister formation decreases and ichthyosis worsens. Skin involvement is most often generalized, with palm and plantar involvement, but some patients have patchy or limited skin lesions. The disease can be life-threatening at birth, secondary to sepsis. BCIE persists into adulthood, with hyperkeratosis of variable intensity and extension. The disease is caused by mutations in the KRT1 (12q11-q13) and KRT10 (17q21-q23) genes encoding keratins 1 and 10, respectively. These mutations impair keratin filament formation and weaken the structural stability of the keratinocyte cytoskeleton. Transmission is autosomal dominant. The diagnosis is based on histological examination of skin lesion biopsies revealing hypergranulosis with orthokeratosis, a thickened stratum corneum, and cytolysis in the upper stratum spinosum and granular layers (epidermolytic hyperkeratosis). Electron microscopy shows tonofilament clumping in the supra basal layers of the epidermis. Genetic tests confirm the diagnosis. Differential diagnoses include ichthyosis bullosa of Siemens, toxic epidermal necrolysis and inherited epidermolysis bullosa (see these terms). Management is symptomatic. Keratolytics can improve localized hyperkeratotic lesions. Oral retinoids (acitretin) provide an effective treatment for hyperkeratosis, but they can have adverse effects on skin fragility and must be used with caution because of their secondary effects. Antibiotic therapy is often required to treat secondary infection. The prognosis is severe and the condition may cause considerable social handicap. |