Necrobiosis lipoidica diabeticorum is an unusual dermatologic condition with a 
characteristic clinical appearance and a clear association with diabetes 
mellitus. There is currently no treatment that reverses the atrophic changes 
associated with this lesion. We have carried out a clinicopathologic study on 15 
subjects and, in addition, have reviewed 10 further biopsy specimens of 
necrobiosis lipoidica diabeticorum. We found a frequent association of 
necrobiosis lipoidica diabeticorum with other chronic complications of diabetes 
mellitus, including limited joint mobility. It is possible that nonenzymatic 
glucosylation or other changes in collagen may be important in the etiology of 
necrobiosis lipoidica diabeticorum and the limited joint mobility. We confirmed 
that cutaneous anesthesia is usually present in the necrobiosis lipoidica 
diabeticorum lesions. With the use of an antibody to S100 protein and an 
immunohistochemical method, there was an apparent decreased number of nerves in 
the skin lesions. We suggest that sensory loss results from local destruction of 
cutaneous nerves by the inflammatory process. Finally, in six elliptical 
biopsies extending into clinically normal skin, we demonstrated that the 
inflammatory infiltrate of necrobiosis lipoidica diabeticorum extended from the 
lesion into apparently normal skin surrounding clinically active lesions. Thus, 
intradermal steroids might be administered to perilesional areas surrounding 
active lesions in the hope of halting progression.