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Perforating collagenosis

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Perforating collagenosis
Molly Yancovitz MD, Hillary Johnson MD PhD, Nadia Wang MD, Miriam K Pomeranz MD
Dermatology Online Journal 14 (10): 14

Department of Dermatology, New York University


A 55-year-old man presented with a three-week history of pruritic, erythematous papules with hyperkeratotic dells on the dorsum of the left hand, which was preceded by swelling, redness and itching. Histopathologic examination showed an acanthotic epidermis with a central invagination filled with a plug composed of parakeratotic debris, collagen, and inflammatory cells. These findings are consistent with acquired reactive perforating collagenosis, which is most frequently reported in patients with pruritus and underlying diabetes mellitus or chronic renal insufficiency. Topical and oral retinoids and topical and intralesional glucocorticoids have been reported to be effective in some patients in case series.

Figure 1Figure 2


A 55-year-old man presented to the Dermatology Clinic at Bellevue Hospital Center in September, 2007, with a one-day history of a swollen, pruritic, non-painful left hand. Swelling improved after empiric therapy with cephalexin and hydroxyzine hydrochloride; however, at a follow-up visit three weeks later, he had pruritic lesions on the left hand. No fevers, chills, pain, or malaise were present. Past medical history includes diabetes mellitus, hypertension, hyperlipidemia, and hypogonadism. Medications included metformin, pioglitazone, insulin, lisinopril, ezetimibe/simvastatin, and testosterone. The patient had no known drug allergies. A biopsy specimen was obtained from the left hand, and the patient was started on triamcinolone cream and clindamycin solution with improvement of lesions.

Physical Examination

On the dorsal aspect of the left hand were three erythematous, firm papules with central hyperkeratotic dells. The forearms were noted to have many hyperpigmented macules.




The epidermis is acanthotic with a central invagination filled with a plug composed of parakeratotic debris, collagen, and inflammatory cells. The epidermis underlying the plug is thin and traversed by vertically oriented collagen fibers.


Reactive perforating collagenosis is a rare skin condition, which is characterized by the development of keratotic papules after superficial trauma. There are two distinct forms: an inherited form in childhood and an acquired form in adults, which was first described in 1982 [1]. The occurrence of acquired reactive perforating collagenosis has most frequently been noted in patients with diabetes mellitus or renal insufficiency, particularly in patients on dialysis. Less commonly, it has been reported in association with a range of other diseases, which include malignant, endocrinologic, and hepatic disorders; neurodermatitis; and atopic dermatitis [1, 2, 3]. Acquired reactive perforating collagenosis is alternatively classified as acquired perforating dermatosis, a term that encompasses all perforating skin lesions in adults with histopatholologic features consistent with one of the primary perforating disorders, such as Kyrle disease, reactive perforating collagenosis, perforating folliculitis, or elastosis perforans serpiginosa [4, 5, 6, 7].

Acquired reactive perforating collagenosis typically presents as pruritic papules on the extensor surfaces of the extremities and dorsa of the hands although they can occur on the trunk and face. Lesions often are preceded by pruritus and scratching, and a Koebner reaction is frequently noted [1, 2]. The lesions are flesh-colored, dome-shaped papules with a keratinous plug, which grow over a few weeks and then heal with scars.

The pathogenesis of this disorder is not known, but it is thought to be an abnormal response to scratching or other trauma, which leads to epidermal hyperplasia and transepithelial extrusion of collagen [4, 6]. One proposed mechanism involves the elimination of abnormal collagen; however, no structural alterations in collagen have been identified [8, 9]. Others have suggested that trauma from scratching causes dermal necrosis secondary to vasculopathy in predisposed patients, which is followed by extrusion of necrotic dermal material through the epidermis [4]. However, the exact mechanisms have yet to be elucidated.

Histopathologically, there is a dome-shaped, hyperkeratotic plug in the epidermis, which often perforates through the epidermis, with transepidermal elimination of collagen fibers in the plug. Macrophages, multinucleated giant cells, lymphocytes, or neutrophils can be found in the plug or in the dermis at the site of perforation [1, 10].

Treatment options for acquired reactive perforating collagenosis include topical and intralesional glucocorticoids, topical and oral retinoids, topical keratolytics, cryotherapy, doxycycline, allopurinol, and ultraviolet B phototherapy, each of which has been successful in clearing a portion of patients [2, 11, 12, 13]. Some patients have noted resolution of lesions with improved control of diabetes mellitus or spontaneous resolution over weeks to months. Other patients continue to experience recurrent lesions despite the above interventions.


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