most common
neuroischemic ulcer
bites/burns/radiation/stings
external/traumatic
pyoderma gangrenous/vaculitis
inflammatory
mycobacterium fungal/necrotizing faciitis
infection
calciphylaxis/epidermolysis bullos
metabolic/genetic
basal cell/kaposi sarcoma
neoplasms
antiphospholipid antibody syn
vasculopathies