Acquired reactive perforating collagenosis (dermatosis) in diabetes mellitus

History and admission findings: A 70-year-old woman with type 2 B diabetes mellitus was referred to the dermatology department because of inflammatory skin changes of unknown origin over the trunk and limbs. On admission foll icular and parafollicular livid-red papulae with central crusts and reddene d margins were noted over the lower legs and the lumbosacral region. Investigations: Further physical examination revealed no additional abnorma lities. Erythrocyte sedimentation rate was 41/79 mm. The day-time blood-glu cose profile was raised (10.2, 12.6 and 8.6 mmol/l), as was the glycosated haemoglobin HbA1c (9.0%). Swabs from fresh lesions gave no evidence of fung al or bacterial infection. Biopsies revealed areas of widened epidermis wit h central ulceration filled with fibrin, granulocytes and collagen fibres. Diagnosis, treatment and course: The clinical and histological findings ind icated an acquired reactive perforating collagenosis (dermatosis) which sho uld be judged in relation to the long-standing diabetes mellitus. The cutan eous changes were covered with salicylate- and steroid-containing preparati ons, while individual lesions were excised or removed by curettage. Conclusion: The condition of acquired reactive perforating collagenosis is, like Kyrle's disease (perforating follicular and parafollicular hyperkerat otic dermatosis), perforating serpiginous elastosis and perforating follicu litis classified among the perforating dermatoses. In the presence of renal failure and (or) diabetes mellitus these dermatoses must be thought of in the differential diagnosis, in addition to the more frequent pruriginous co nditions, if there are corresponding skin changes.