<prompt> Recessive dystrophic epidermolysis Bullosa occurs due to alteration in:Type 4 collagenType 6 collagenType 7 collagenType 8 collagen  <response>: Nikolskys sign is positive in: PemphigusFamilial benign chronic pemphigus hailey-hailey diseaseRecessive dystrophic epidermolvsis bullosa Epidermolysis bullosa occurs due to alteration in structure of type VII collagen. 