ABSTRACT
EPIDEMIOLOGY AND ETIOLOGY In general, systemic sclerosis (SSc) has an estimated annual incidence ranging from 0.45 per 100,000 to 1.9 per 100,000, and a prevalence of approximately 15-24 per 100,000 (Mayes et al. 2003). Onset in childhood is very uncommon: children under 16 years account for less than 5% of all cases (Scalapino et al. 2006) and fewer than 10% develop SSc before the age of 20 (Black 1999, Kornreich et al. 1977, Medsger 1994). The onset occurs at a mean age of 8.1 years and the peak age is between 10 and 16 years (Martini et al. 2006, Scalapino et al. 2006). The disease is almost four times more frequent in females and there is no racial predilection (Martini et al. 2006).
