Epidermolytic Ichthyosis (!)
- Due to KRT1, KRT10 mutations (KRT=keratin)
- Impaired keratin alignment, oligomerization and filament assembly → weakened keratin helical structure and cellular integrity in the stratum corneum
- → acanthosis (histology), blistering (clinically)
- → transepidermal waterloss, bacterial colonization
- Distinguir do mecanismo de palmoplantar keratoderma
- Se mutação em zona crítica da Keratin 1 → Epidermolytic Ichtyosis (efeito dominante negativo, fenótipo generalizado)
- Se mutação fora da zona crítica da Keratin 1 → Unna Thost non-epidermolytic isolated plamoplantar keratoderma (fenótipo limitado às palmas e plantas)
- Pode existir em mosaico → epidermal nevus
- Histology
- Clumps of keratin tonofilaments in affected keratinocytes in stratum spinosum
- Overlying epidermis becomes acanthotic and hyperkeratotic due to reactive hyperproliferation and decreased desquamation
- Kyperkeratosis, keratinocyte vacuolization & a prominent granular layer with clumped keratin in suprabasal cells; lamellar body accumulation
- Clinical presentation
- At birth: erythroderma, blistering and erosions
- May lead to sepsis, fluid and electrolyte imbalences, death
- Later:
- hyperkeratosis with cobblestone pattern
- “corrugated cardboard” most prominent over joints & flexures
- disfiguring
- blisters and secondary bacterial infection
- Palmoplantar involvement may lead to digital contractures
- K9 is present in palmar/plantar skin & can replace K10
- K1 mutations produce severe palmoplantar keratoderma
- K10 mutations usually spare palms and soles
- Foul odor, superinfections
- Diagnosis: histology, gene sequencing
- Treatment
- Neonatal period: supportive care in NICU
- In children and adults: keratolytic agents, retinoids, emollients, humectants
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