Reactive perforating collagenosis: An important differential diagnosis in hemodialysis patients

This is a case report of a 68-year-old hypertensive, diabetic woman who was on regular thrice weekly hemodialysis (HD). She presented with gradually worsening left lower limb pain and swelling. Clinical examination revealed significant edema over the left calf and ankle joint with significant calf tenderness. Extensive workup including magnetic resonance imaging of the lower limb and venous Doppler failed to show any significant abnormality. In view of developing papular lesions over the area, skin biopsy was performed, which finally confirmed reactive perforating collagenosis. This diagnosis ensured reassurance to the patient with halting of further extensive and probably expensive testing. Simple conservative management and symptomatic relief improved the pain over the next few days. This case report highlights the importance of keeping a wide differential for calf tenderness in diabetic HD patients and projects reactive perforating collagenosis as one of the important but frequently missed entities in such a scenario.