Transient neutropenia in children with febrile illness and associated infectious agents: 2 years' follow-up.

The aim of the study was to identify the relationship of acquired neutropenia with childhood infections and to assess its clinical course, complications, and outcome. Children admitted to two pediatric wards over a 4-year period with febrile neutropenia were prospectively investigated for underlying infections with inflammatory markers, cultures of body fluids, and serological tests. The study included 161 previously healthy children with febrile neutropenia/leukopenia aged (mean ± SD) 3.02 ± 3.86 years (range, 0.1-14). One hundred and thirty-six out of 161 patients (84.5 %) had transient neutropenia (TN), while in 25 patients, neutropenia was chronic (CN) and persisted for ≥180 days. An infectious agent was isolated in 98/161 (60.9 %) cases, in 68.4 % patients with TN, and in 20 % of those with CN (p = 0.001). Among the patients with CN, seven had positive antineutrophil antibodies (autoimmune neutropenia) and four were eventually diagnosed with hematological malignancy. In all age groups, TN was of short duration (<1 month), of mild to moderate severity, and was predominantly associated with viral infections. Two years after diagnosis, 143/161 children (88.8 %) were available for follow-up. One hundred and thirty-seven of 143 (95.8 %) had recovered completely, while the rest remained neutropenic. The latter patients had a benign course despite severe neutropenia. In conclusion, febrile neutropenia during childhood is usually transient, often following viral and common bacterial infections, without serious complications and in the majority of cases it resolves spontaneously. However, in a considerable percentage of patients, neutropenia is discovered incidentally during the course of an infection on the ground of an underlying hematological disease.