Juvenile scleroderma syndromes are multisystem autoimmune rheumatic diseases for which the unifying characteristic is the development of hard skin before age 16. They can be separated into 2 main categories: 1) juvenile systemic sclerosis (JSSc), characterized by diffuse skin sclerosis involving many sites of the body together with internal organ involvement, and 2) juvenile localized scleroderma (JLS), characterized by circumscribed skin induration but no vascular or internal organ involvement.
JUVENILE SYSTEMIC SCLEROSIS
JSSc is a chronic multisystem connective tissue disease characterized by the symmetrical thickening and hardening of the skin, associated with fibrous changes in such internal organs as the esophagus, intestinal tract, heart, lungs, and kidneys, plus arthritis and myositis. A Committee on Classification Criteria for JSSc, including pediatricians, rheumatologists, and dermatologists, recently proposed new classification criteria (Table 203-1).
TABLE 203-1PRELIMINARY CLASSIFICATION CRITERIA FOR JUVENILE SYSTEMIC SCLEROSIS ||Download (.pdf) TABLE 203-1PRELIMINARY CLASSIFICATION CRITERIA FOR JUVENILE SYSTEMIC SCLEROSIS
|Major Criterion |
|Proximal sclerosis/induration of the skin |
|Minor Criteria |
|Skin ||Sclerodactyly |
|Vascular ||Raynaud phenomenon |
|Nailfold capillary abnormalities |
|Digital tip ulcers |
|Gastrointestinal ||Dysphagia |
|Gastroesophageal reflux |
|Renal ||Renal crisis |
|New onset arterial hypertension |
|Cardiac ||Arrhythmias |
|Heart failure |
|Respiratory ||Pulmonary fibrosis (high-resolution computed tomography/x-ray) |
|Reduced diffusion capacity for carbon monoxide (DLCO) |
|Pulmonary hypertension |
|Musculoskeletal ||Tendon friction rubs |
|Neurologic ||Neuropathy |
|Carpal tunnel syndrome |
|Serology ||Antinuclear antibodies |
|SSc selective autoantibodies (anticentromere, antitopoisomerase I, antifibrillarin, anti-PM-Scl, antifibrillin, or antiRNA polymerase I or III) |
EPIDEMIOLOGY AND PATHOGENESIS
Systemic sclerosis is a rare condition in any age group. Onset in childhood is particularly uncommon: the estimated incidence is approximately 0.27 cases per million children per year. Children younger than age 16 years account for fewer than 5% of all cases, and fewer than 10% develop systemic sclerosis before reaching age 20. JSSc develops at a mean age of 8.1 years, with a peak incidence between ages 10 and 16. The disease is almost four fold more prevalent in females, but there is no recognized racial predilection.
The cause of systemic sclerosis is unknown, and the pathogenesis appears to be complex. The process involves 3 components: immune activation, endothelial (vascular) damage, and excessive synthesis of extracellular matrix with increased deposition of structurally normal collagen. Genetic factors appear to increase susceptibility to development of systemic sclerosis.