A 41 year-old woman presented with multiple, 2 year-old, scattered erythematous to brownish papules with pruritus on both legs. She had diabetes mellitus. The initial clinical suspicion was reactive perforating collagenosis and punch biopsy was performed. Atrophic and ulcerative epidermis was observed. There was cup-shaped invagination of the epidermis associated with a keratin plug containing inflammatory debris and collagen fibers (d,e). Reactive perforating collagenosis and prurigo nodularis were finally diagnosed. After the use of oral cyclosporine (100 mg/day) for 4 weeks without improvement, oral alitretinoin (30 mg/day) was started. Within 5 weeks of alitretinoin treatment, her pruritus and skin lesions improved. After that, she stopped medical treatment without progression or recurrence.
A 78 year-old man diagnosed with prurigo nodularis had itchy multiple erythematous to brownish papules on both flanks, chest, and back that were 6 months old. He had no underlying disease. Oral cyclosporine (50 mg/day) was taken for 1 year. His symptoms waxed and waned. In our study, oral alitretinoin (30 mg/day) was started. Within 2 weeks of treatment, the skin lesions and pruritus had improved. The patient was treated with oral alitretinoin for 14 weeks until complete remission and then the treatment was stopped without recurrence.