Lamina lucida and anchoring filaments
Adhesion & dermo-epidermal junction · Laminin-332 Weakest plane Salt-split roof
The narrow zone between the basal keratinocyte membrane and the lamina densa, crossed by anchoring filaments of laminin-332 and the BP180 ectodomain. Mechanically it is the weakest plane of the junction, so most subepidermal blisters and the laboratory salt-split both separate here.
Traced from the start
- Stratum basale (germinativum)
- Lamina lucida and anchoring filaments
Detail
- Contents
- Anchoring filaments composed of laminin-332 with the ectodomain of BP180
- Salt-split skin
- 1M sodium chloride separates normal skin through this zone; bullous pemphigoid serum binds the epidermal roof, epidermolysis bullosa acquisita and anti-p200 serum bind the dermal floor
- Blister character
- Subepidermal split, so the blister roof is full-thickness epidermis: tense, slow to rupture, heals without scarring unless the split is below the lamina densa
When it goes wrong
Vancomycin exposure (linear IgA bullous dermatosis)
Linear IgA along the basement membrane and blisters arising in annular groups within days to weeks; resolves on stopping the drug, otherwise treated with dapsone
Antibodies to laminin-332 (a subtype of mucous membrane pemphigoid)
Scarring conjunctival and oral disease that can blind, and an association with underlying solid malignancy that warrants a search
Practise this structure
16 questions in the bank tagged Skin.
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