Reactive perforating collagenosis

Reactive perforating collagenosis (RPC) was first described as an independent inflammatory skin disease by Mehregan and Pinkus in 1967.

Perforating collagenosis, reactive perforating dermatosis

Reactive perforating collagenosis is a rare, chronic recurrent perforating dermatosis characterised by transepidermal elimination of degenerated collagen. The exact pathogenesis is not yet fully understood, but there is an association with various systemic diseases such as diabetes mellitus and renal insufficiency.

Reactive perforating collagenosis is rare and the exact prevalence is unknown. The disease affects both children and adults, although a familial clustering is often observed in children.

The disease is divided into two main types:
a) Acquired reactive perforating collagenosis (ARPC)

• Primary or idiopathic RPC
• Secondary RPC associated with other diseases such as diabetes mellitus, renal insufficiency or atopic dermatitis

b) Familial reactive perforating collagenosis (FRPC)

The exact pathogenesis of reactive perforating collagenosis is not yet fully understood. It is suspected that a disorder in collagenolysis or excessive collagen production plays a role. An association with various systemic diseases such as diabetes mellitus and renal insufficiency has been observed.

Reactive perforating collagenosis is clinically manifested by very itchy, raised, erythematous papules that undergo central umbilicalisation and later show crusty healing areas.

The diagnosis of reactive perforating collagenosis is based on clinical presentation, histopathological examination of skin biopsies and the exclusion of other perforating dermatoses.

The lesions typically occur on the extensor sides of the extremities, trunk and limbs.

Patients with reactive perforating collagenosis often report a history of itchy skin lesions that develop spontaneously and are accompanied by scratch marks.

Histologically, reactive perforating collagenosis shows transepidermal elimination of degenerated collagen, accompanied by inflammatory cell infiltration.

Possible complications of reactive perforating collagenosis include secondary infections, scarring and an increased risk of developing Koebner's phenomenon, in which skin lesions occur at sites affected by injury or irritation. There is also regular post-inflammatory hyperpigmentation in higher skin types.

The prognosis of reactive perforating collagenosis is variable. In some patients, the disease can remit spontaneously, while in others it is chronic and relapsing. The acquired form can progress differently depending on the underlying systemic disease.

As the exact pathogenesis of reactive perforating collagenosis is not yet fully understood, there are no specific prophylactic measures. However, early identification and treatment of associated systemic diseases can reduce the risk of complications.

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