Acquired reactive perforating collagenosis: a rare association with dermatomyositis.

Acquired reactive perforating collagenosis (ARPC) presents with a number of umbilicated papules and nodules with central keratotic plugs on the trunk and extremities. Histopathology shows necrobiotic basophilic collagen bundles running transversely through the epidermis. ARPC is seen in association with various systemic disorders, in particular uncontrolled diabetes mellitus or renal failure (1). We describe here 2 patients with clinically amyopathic dermatomyositis, who developed ARPC on the back. A 74-year-old woman visited our hospital, with itchy eruptions on her head and neck, trunk and extremities. Physical examination revealed erythema on the eyelids, forehead, and nasolabial areas (Fig. 1a). Coalescent erythema was found on the trunk and extremities. Nodular lesions with keratotic plugs were scattered on the lower back, which gradually worsened and increased in number (Fig. 1b). Electromyography of her biceps and quadriceps femoris showed no significant changes. Results of laboratory examination showed elevated creatine kinase (CK) level (462 IU/l; normal < 200 IU/l), aldolase level (9.3 U/l; normal < 5.0 U/l), myoglobin (103.5 ng/ml; normal < 60 ng/ml), C-reactive protein (CRP) and erythrocyte sedi-mentation rate (ESR) (33 mm/h). Renal function was normal. Antinuclear antibody and anti-Jo-1 antibody were within normal ranges, while anti-hepatitis C virus (HCV) antibody was detected. Blood glucose was 129 mg/dl (normal 70–109 mg/ dl) and HbA1c was 5.8% (normal 4.3–5.8%). No lung fibrosis was revealed. A skin biopsy of a nodule showed a cup-shaped depression in the epidermis, and transepidermal elimination of basophilic collagen bundles, surrounded by a lymphocytic and neutrophilic infiltration (Fig. 1c). Elastica van Gieson staining revealed degenerated collagen fibres transversely eliminated through the epidermis (Fig. 1d). A 56-year-old woman with lung fibrosis was referred to our department for cutaneous manifestations. Physical examination showed eyelid erythema, mechanic's hand on the lateral aspects of the second fingers, and seborrhoeic dermatitis-like erythema on the face (Fig. 2a, b). Muscle weakness was not observed. Serum CK was normal, and abnormal laboratory data included increased levels of ESR (63 mm/h), AST (178 U/l; normal 13–33 U/l), ALT (86 U/l, 6–27 U/l), lactate dehydro-genase (LDH) (648 U/l, 119–229 U/l), and KL-6 (1,315 U/ ml; < 500 U/ml). Renal function was normal. Blood glucose was 101 mg/dl, and HbA1c (5.5%) were within upper limits. Antinuclear antibody and anti-Jo-1 antibody were within normal ranges, while anti-SS-A antibody was positive (49.0 U/ml, < 7 U/ml). The patient reported having pruritus, and four weeks later several nodules, which increased in number, appeared on …