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 42 year-old man presented with multiple scaly erythematous itchy papules on the whole body that were 12 months old. He had hypertension and diabetes mellitus. The clinical diagnosis was prurigo nodularis and treatment was started. Despite taking oral antihistamine and cyclosporine (200 mg/day) for 4 weeks, the patient’s symptoms were not improved. Medication was changed to oral alitretinoin in a dose of 30 mg/day. Within 5 weeks of treatment, symptoms had improved. The treatment of oral alitretinoin was continued for 12 weeks until complete remission and was stopped afterward without recurrence.