A 59-year-old man with chronic renal failure and diabetes mellitus presented with pruritic crusted lesions which histologically were perforating disorders, showing features of both Kyrle disease and acquired perforating collagenosis. The mechanisms of transepidermal elimination and the classification of perforating disorders are briefly discussed. Additionally, we question the concept of perforation, as epidermal damage and exposure of subepidermal substances may artificially present as perforation
