DSG1 and acquired polycythemia vera: PF does not involve mucosa and only has desmoglein-1 autoantibodies, while pemphigus vulgaris (PV) is mucocutaneous and has both desmoglein-1 and desmoglein-3 autoantibodies [8]. Other causes of erythroderma, including psoriasis, systemic response to scabies, seborrheic dermatitis, and cutaneous T-cell lymphoma, were subsequently ruled out by biopsy results.