RECURRENT IMMUNE THROMBOCYTOPENIC PURPURA IN CHILDREN

We read with interest the article by Jayabose et al. entitled “Recurrent Immune Thrombocytopenic Purpura in Children” [[1]]. The article has raised a very interesting issue. Pediatric hematologists frankly don't know how to classify children with so-called “recurrent” ITP. For practical reasons, the most acceptable definition is the recurrence of ITP after at least 3 months of remission sustained without any treatment.

We retrospectively reviewed hospital records of 79 children with ITP treated from 1991 to 2006 at the University Children's Hospital Rijeka, Croatia [[2]]. Three patients (3.8%) met the criteria of recurrent ITP, two males and a female. The median age at initial presentation was 3.3 years (range 1.2–4.5). The median platelet count was 25.7 × 10⁹/L (1–51). Two patients presented with cutaneous purpura, and one with mucocutaneous bleeding. The median time to achieve initial complete remission was 6.7 months (1–10). The initial course was acute in a female, and chronic in two males. The median age at the time of first recurrence was 4.7 years (2.6–5.8). The median time to recurrence was 10.3 months (7–15). The nadir platelet count at first recurrence was 19.7 × 10⁹/L (4–43). The median time to achieve second remission was 2.3 months (1–5). Two males experienced second relapse within 6 and 21 months, with the platelet count 38 and 8 × 10⁹/L. The interval to achieve third remission was 1 month in either.

A spontaneous recovery occurred in all 3 patients with “recurrent” ITP over a period of time ranging from 21 to 40 months after the initial presentation. In all patients observation alone was the only clinical option. We could not recognize any potential risk factor responsible for a recurrent disease. The median duration of total follow-up was 97.7 months (71–132).

Although in some reviews recurrent ITP is included as a separate form, distinct from acute and chronic ITP, this is probably incorrect. Recurrent ITP is believed by most pediatric hematologists to be an exacerbation during the course of a compensated chronic ITP [[3]]. The incidence in our study was consistent with earlier reports. Recurrent disease occurred in children who recovered a normal platelet count within a year after initial diagnosis. Clinical and laboratory features did not differ from acute ITP (young age, preceding viral infection, abrupt onset of symptoms, low platelet count). The platelet count normalized within 1–5 months of exacerbation. The recurrence of thrombocytopenia did not influence an excellent prognosis of these patients. The clinical course in this series could be characterized as “recurrent acute ITP” or what has also been called “intermittent acute ITP” [[4]]. However, the significance of our findings is limited, because of the small size of the study.

While the precise pathophysiology and long-term outcome of a large number of children with ITP are still to be elucidated, it seems improper to arbitrarily separate these patients into different groups or subsets. Prospective international trials are required to address the controversies surrounding childhood ITP.