A 54 year-old man had developed several scattered, itchy, excoriated erythematous papules on both the arms and back (5 years previously). He had no underlying disease. The clinical diagnosis was prurigo nodularis and treatment was started. Oral cyclosporine (200 mg/day) was taken for 1 year, but his symptoms waxed and waned. Treatment was changed to oral alitretinoin (30 mg/day). Within 16 weeks of treatment, the symptoms and skin lesions had improved more than with previous treatment. His treatment with oral alitretinoin continued for 3 years without progression or any side effects.
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.