Toxic epidermal necrolysis (TEN) is a form of erythema multiforme syndrome that involves at least 30% of body surface area. Edema develops in the superficial dermis, where vesicles and bullae form, rupture, and form erosions and crusts. Necrosis can occur in the epidermis, air passages, upper digestive tract, urethra, and conjunctiva. TEN syndrome can also involve the kidneys and extend into the lungs. Severe forms can be fatal. Stevens-Johnson syndrome is also characterized as an erythema multiforme syndrome, but if the mucocutaneous bullous involves only 10% of body surface area. Pemphigus is a group of rare autoimmune blistering diseases that affects the skin and oral mucous membranes. Pemphigus vulgaris is the most common. Pemphigus vegetans is a variant of vulgaris in which large blisters form in the tissue folds of the axilla and groin.