Presence of Thrombocytopenia at Onset Is Associated with Severe Disease Course in Juvenile Dermatomyositis: An Experience from a Tertiary Care Centre in North India

Objectives: To analyse the clinical profile of children with Juvenile Dermatomyositis (JDMS) who had thrombocytopenia (<150 × 10 9 /L) at disease onset and compare them with patients who had normal platelet counts. Methods: Children diagnosed to have JDMS based on modified Bohan and Peter criteria and being followed up in a tertiary care referral hospital in North India were analysed. Collected data included clinical profile, laboratory investigations, treatment details, and outcome. Results: We analysed 131 patients with JDMS. Fourteen amongst these (10.7%) had thrombocytopenia at initial diagnosis. None of them had evidence of sepsis, overlap syndrome or macrophage activation syndrome. Median time for improvement of thrombocytopenia was 1.4 months (IQR: 0.4–6 months). Patients with thrombocytopenia had late onset of disease (9.9 vs. 6 years, P = .008). Amongst the cutaneous manifestations, periorbital swelling [10 vs. 49, P = .047] and anasarca [3 vs. 2, P = .009] were seen more with thrombocytopenic patients. The number of patients with severe muscle disease (28 vs. 48, P = .001), respiratory muscle weakness [5 vs. 6, P = .002], pharyngeal weakness [9 vs. 40, P = .040], and gastrointestinal vasculopathy [5 vs. 1, P = .001] was high in the thrombocytopenic group. Median time required to achieve remission was longer in the thrombocytopenic group (8 vs. 4.5 months, P = .011). Mortality rate was also high in the thrombocytopenic group [3 (21.45%) vs. 7 (5.9%)]. Conclusion: Children with thrombocytopenia at onset in JDMS showed severe disease activity, high rates of relapse, and mortality. Thrombocytopenia at disease onset in JDMS could be considered as a potential laboratory marker to predict a severe disease course and outcome.