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Scleroderma and Raynaud Phenomenon


Juvenile scleroderma encompasses a range of conditions unified by the presence of fibrosis of the skin. Juvenile scleroderma is divided into 2 major categories, juvenile localized scleroderma ( JLS , also known as morphea ), which is largely limited to the skin, and juvenile systemic sclerosis ( JSSc ), with multisystem organ involvement. Localized disease is the predominant type seen in pediatric populations (>95%), but systemic sclerosis is associated with mortality and severe multiorgan morbidity.

Etiology and Pathogenesis

The etiology of scleroderma is unknown, but the mechanism of disease appears to be a combination of a vasculopathy, autoimmunity, immune activation, and fibrosis. Triggers, including trauma, infection, and, possibly, subclinical graft-versus-host reaction from persistent maternal cells ( microchimerism ), injure vascular endothelial cells, resulting in increased expression of adhesion molecules. These molecules entrap platelets and inflammatory cells, resulting in vascular changes with manifestations such as Raynaud phenomenon and pulmonary hypertension. Inflammatory cells infiltrate the area of initial vascular damage, causing further vascular damage and resulting in thickened artery walls and reduction in capillary numbers. Macrophages and other inflammatory cells then migrate into affected tissues and secrete cytokines that induce fibroblasts to reproduce and synthesize excessive amounts of collagen, resulting in fibrosis and subsequent lipoatrophy, dermal fibrosis, with loss of sweat glands and hair follicles. In late stages the entire dermis may be replaced by compact collagen fibers.

Autoimmunity is believed to be a key process in the pathogenesis of both localized and systemic scleroderma, given the high percentage of affected children with autoantibodies. Children with localized disease often have a positive antinuclear antibody (ANA) test result (42%), and 47% of this subgroup have antihistone antibodies. Children with JSSc have higher rates of ANA positivity (80.7%) and may have anti–Scl-70 antibody (34%, antitopoisomerase I). The relationship between specific autoantibodies and the various forms of scleroderma is not well understood, and all antibody test results may be negative, especially in JLS.

Classification

Localized scleroderma is distinct from systemic scleroderma and rarely progresses to systemic disease. The category of JLS includes several subtypes differentiated by both the distribution of the lesions and the depth of involvement ( Tables 185.1 and 185.2 ). Up to 15% of children have a combination of 2 or more subtypes.

Table 185.1
Classification of Pediatric Scleroderma (Morphea)

Localized Scleroderma

Plaque Morphea

  • Confined to dermis, occasionally superficial panniculus

  • Well-circumscribed circular area of induration, often a central waxy, ivory-colored area surrounded by a violaceous halo; unilateral

Generalized Morphea

  • Involves dermis primarily, occasionally panniculus

  • Defined as confluence of individual morphea plaques or lesions in ≥3 anatomic sites; more likely to be bilateral

Bullous Morphea

  • Bullous lesions that can occur with any of the subtypes of morphea

Linear Scleroderma

  • Linear lesions can extend through the dermis, subcutaneous tissue, and muscle to underlying bone; more likely unilateral

  • Limbs/trunk:

    • One or more linear streaks of the extremities or trunk

    • Flexion contracture occurs when lesion extends over a joint; limb length discrepancies

  • En coup de sabre:

    • Involves the scalp and/or face; lesions can extend into the central nervous system, resulting in neurologic sequelae, most commonly seizures and headaches

  • Parry-Romberg syndrome:

    • Hemifacial atrophy without a clearly definable en coup de sabre lesion; can also have neurologic involvement

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