In acute exacerbation of pemphigus vulgaris requiring emergency management, which parameter BEST guides the decision to initiate plasma exchange (plasmapheresis) as an adjunct?
- A Serum anti-desmoglein-1 titre >500 U/mL
- B Skin detachment >30% BSA unresponsive to high-dose steroids and rituximab ✓
- C Positive direct immunofluorescence showing IgG intercellular
- D Peripheral eosinophilia >1500/mm³
Correct answer: B. Skin detachment >30% BSA unresponsive to high-dose steroids and rituximab
Explanation
Plasmapheresis is reserved for severe pemphigus that is refractory to high-dose systemic corticosteroids and other immunosuppressants, typically when disease is life-threatening with extensive involvement (>30% BSA) or when rapid antibody removal is clinically necessary. Serum DSG titres and DIF results guide diagnosis but not the specific threshold for plasmapheresis. Eosinophilia is non-specific.
Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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