8-Year-Old Girl with Polymorphic Scars on the Face

An 8-year-old girl borne of consanguineous marriage presented with mildly itchy papules on extremities and face. She also had multiple scars on face and arms for the past 6 years. There was history of aggravation of the lesions in winters. On examination, few well-defined erythematous papules of size 3-5 mm with central adherent keratotic plug resolving with multiple shallow, circular and linear atrophic scars were present on the face, and dorsum of hands. [Figure 1]. Koebnerization was present on the face and dorsum of both hands. Histopathological examination of the skin biopsy showed orthokeratosis and a cup-shaped lesion which was lined on both sides by acanthotic epidermis. This cup-shaped lesion was densely packed with degenerated basophilic collagen bundles [Figure 2]. These collagen bundles were better highlighted on Masson's trichrome stain [Figure 3]. Based on history, physical examination and histopathological findings, a diagnosis of reactive perforating collagenosis was rendered. The child was advised 10 mg oral acitretin, antihistamines, and emollients.

Figure 1.

Multiple round to linear atrophic scars, and few erythematous papules with central keratotic plugs on the face

Figure 2.

Histopathology: Skin biopsy showed cup shaped depression containing parakeratotic cells intermingled with basophilic material and degenerated collagen bundles in the epidermis (Hematoxylin and eosin, ×200)

Figure 3.

Masson's trichome stain revealed the transepidermal eliminated material as collagen (Masson's trichrome stain, ×200)

Reactive perforating collagenosis (RPC) is a rare perforating disorder characterized by transepidermal elimination of altered collagen from the epidermis. Two distinct subsets of RPC have been identified-- inherited and acquired, the latter being more common in adults with diabetes and/or chronic renal failure. Other associations of acquired variant include hypothyroidism, hyperparathyroidism, liver disorders, Hodgkin's disease, neurodermatitis, HIV, and immunoglobulin A nephropathy.[1] The inherited form can be autosomal-recessive, autosomal-dominant or sporadic, and is frequently seen in males in first 2 decades of life.[2] The clinical manifestations in both forms are similar except pruritus is more common in the acquired type.[2] Predisposing factors include physical trauma and cold temperature which induce the degeneration of collagen and thinning of epidermis. The transepidermal elimination of damaged collagen is facilitated by the upward movement of proliferating keratinocytes resulting in formation of a vertically oriented channel.[2] Morphologically, the lesions manifest over face and extensors as erythematous to hyperpigmented umbilicated papules and nodules with a central hyperkeratotic plug.[2] The lesions resolve spontaneously within few months leaving a hypopigmented or hyperpigmented scar.

In the index case, presentation in the first year of life favored inherited RPC, while an absence of disease in either parent along with a history of consanguinity pointed toward an autosomal-recessive inheritance. Facial involvement in RPC is more frequently seen in females (as in the present case), whereas extremities are predominantly involved in males.[3] Atrophia maculosa varioliformis cutis is an important differential diagnosis of facial lesions in our patient. It is a type of idiopathic noninflammatory macular atrophy, clinically characterized by shallow, sharply demarcated linear, and punctate scars on the face.[4] Varioliform scarring can also be observed in lipoid proteinosis; however, because of absence of other features including hoarseness of voice and blistering, this was not considered as a differential in our case.[5] Other differential diagnoses include inherited porphyrias, hydroa vacciniforme, and other perforating disorders.

Treatment of reactive perforating collagenosis is often challenging. Lesions are usually self-limiting although recurrences are frequent. Therapeutic options include topical retinoids, topical corticosteroids, intralesional steroids, keratolytics, oral retinoids, psoralen and ultraviolet A, narrow-band ultraviolet B, cryotherapy, allopurinol, doxycycline, and methotrexate.[6]

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