A 61 year-old man presented with several one month-old erythematous to brownish papules and nodules on the back and both legs (a,c). He had diabetes mellitus. The initial clinical suspicion was prurigo nodularis and punch biopsy was done. Microscopic examination showed hyperkeratotic epidermis with acanthosis and parakeratosis. Elongated and irregular rete ridges were observed with dense dermal perivascular infiltration (a,b). The final diagnosis was prurigo nodularis. Initially, he was treated with oral cyclosporine 100 mg/day for 4 weeks. However, relief of the symptoms was insufficient and oral alitretinoin was started at a dose of 30 mg/day. After 4 weeks of alitretinoin treatment, symptoms and skin lesions were improved, and with 8 weeks of treatment (b,d), he stopped medical treatment and achieved complete remission without recurrence.
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.