Childhood idiopathic thrombocytopenic purpura in the Nordic countries: epidemiology and predictors of chronic disease

Acta Paediatr. 2005 Feb;94(2):178-84. doi: 10.1111/j.1651-2227.2005.tb01887.x.


Aim: To describe the epidemiology of idiopathic thrombocytopenic purpura (ITP) in the Nordic countries, to define clinical subgroups and to investigate factors predicting chronic disease.

Methods: A prospective registration was done from 1998 to 2000, including all children with newly diagnosed ITP aged 0-14 y and at least one platelet count <30 x 10(9)/l.

Results: 506 children were registered and 423 followed for 6 mo. The incidence was 4.8/10(5) per year. Most children were aged 0-7 y (78%), with a predominance of boys, while patients aged 8-14 y had equal representation of the two sexes. There were seasonal variations determined by variations in postinfectious cases with sudden onset. The platelet count was <10 x 10(9)/l in 58%, but bleeding manifestations were mild or moderate in 97%. The insidious form (symptoms for more than 2 wk) was more frequent in older children and girls, showed little seasonal variation, had milder manifestations and ran a chronic course in more than half the cases. Intracranial haemorrhages did not occur in the first 6 mo after diagnosis. Chronic ITP developed in 25%. The strongest predictor of chronic disease was insidious onset of symptoms (OR 5.97).

Conclusion: In the Nordic countries, ITP mainly affects children aged 0-7 y, with a winter bulk of postinfectious cases superimposed on a steady occurrence of non-infectious cases. Clinically, it may be useful to distinguish between children with sudden versus insidious onset of symptoms rather than between different age groups.

MeSH terms

  • Acute Disease / epidemiology
  • Adolescent
  • Child
  • Child, Preschool
  • Chronic Disease / epidemiology
  • Female
  • Finland / epidemiology
  • Hemorrhage / epidemiology
  • Hemorrhage / etiology
  • Humans
  • Iceland / epidemiology
  • Incidence
  • Infant
  • Infant, Newborn
  • Male
  • Prognosis
  • Prospective Studies
  • Purpura, Thrombocytopenic, Idiopathic / complications
  • Purpura, Thrombocytopenic, Idiopathic / diagnosis
  • Purpura, Thrombocytopenic, Idiopathic / epidemiology*
  • Risk Factors
  • Scandinavian and Nordic Countries / epidemiology
  • Statistics, Nonparametric