Pemphigus neonatorum is:
High-Yield Explanation
Bullous impetigo Caused by S. aureus S. aureus phage type 2 releases Epidermolytic Toxin (ET). This toxin ruptures desmosomes primarily in subcorneal layer - as the target is desmoglein - 1 (Note : It is a toxin- mediated destruction of Dsg - 1, not autoimmune destruction as in pemphigus foliaceus). The organism can be cultured from blister fluid. The pus settles on lower end of the blister as it is heavier - Hypopyon sign. When the ET causes local skin infection - called bullous impetigo and when it disseminates hematogenously - called Staphylococcus Scalded skin syndrome (SSSS)/Ritter Disease/pemphigus neonatorum. Histopathology- Blister below stratum corneum (within or below the granular layer) with plenty of neutrophils.