Acquired reactive perforating collagenosis in a patient with diabetes

A 47-year-old woman presented with a 2-month history of pruritic eruptions on the left ankle and a complaint of thirst and polyuria for the past year.She was previously healthy and denied a history of insect bites.Physical examination revealed multiple umbilicated hyperkeratotic papules and nodules with a central round crusted ulcer on the left ankle (Figure 1).Histologic study of the lesions revealed cup-shaped invagination of the epidermis plugged with necrotic infl ammatory debris and transepidermal elimination of dermal collagen (Figure 2).Laboratory testing showed the following: • Fasting glucose 7.8 mmol/L [140.4 mg/dL] (reference range 3.9-5.6[70-100]) • Hemoglobin A1c 6.9% • Triglycerides 2.38 mmol/L [210.6 mg/dL] (< 1.7 [< 150]) • Total cholesterol 7.21 mmol/L [278.4 mg/dL] (< 5.18 [< 200]).Based on the clinical presentation and the results of histologic study and blood testing, we diagnosed acquired reactive perforating collagenosis and type 2 diabetes.The patient was referred to endocrinology for management, and her lesions improved after 4 weeks of treatment with loratadine and halometasone cream.