Salt-split skin indirect immunofluorescence is performed on a patient with a tense blistering disorder. Linear IgG deposits are seen along the FLOOR of the artificially induced blister. This finding is most characteristic of:

• A Bullous pemphigoid
• B Epidermolysis bullosa acquisita ✓
• C Linear IgA bullous dermatosis
• D Dermatitis herpetiformis

Explanation

In epidermolysis bullosa acquisita the antibody targets type VII collagen of the anchoring fibrils, which lie below the lamina densa. When salt splits the basement membrane through the lamina lucida, type VII collagen stays on the dermal side, so staining appears on the blister floor. Bullous pemphigoid antibodies bind BP180 and BP230 within hemidesmosomes above the split plane, giving ROOF staining, which is the key discriminating fact.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.