Pathophys:Anti-basement membrane antibodies, usually IgG, occasionally IgE (Nejm 1978;298:417) and IgA in mucus membrane variant
Sx:Similar to pemphigus but in aged, and usually hemorrhagic; less severe than pemphigus; itchy; tense blisters because epidermis intact above split
Rx:Topical better than systemic steroids esp if severe (Nejm 2002;346:321); immunosuppressants like azathioprine (Arch Derm 1994;130:753), cyclophosphamide, etc; antibiotics like tetracycline and niacinamide (Arch Derm 1986;122:670) are steroid sparing; oral steroids