ATOPIC-DERMATITIS AND ALLERGIC DISEASES WITH THROMBOCYTOSIS - A POSSIBLE LINK

Background: Thrombocytosis can be present in patients with myeloprolif erative disorders or can accompany various conditions, in particular c hronic inflammatory diseases, namely chronic bowel diseases, rheumatoi d arthritis, and nephritis. Objective: We report our experience in 55 patients younger than 45 years of age with increased platelet counts ( over 500 X 10(9)/L). Thirty-three were affected by essential thrombocy temia in agreement with polycytemia vera study group criteria and 22 b y reactive thrombocytosis. Serotonin concentration has been determined in all the patients. Results: Serotonin was decreased as expected in 23 out of the 33 patients with essential thrombocytemia. In the remain ing ten subjects, serotonin was within normal Limits as in reactive th rombocytosis. Eight of these subjects had positive histories for aller gic rhinitis and two for atopic dermatitis. Conclusions: Chronic infla mmation, present in patients with diseases of the immune system may ca use an increased platelet number. One should consider with caution pat ients with thrombocytosis and positive histories for diseases of the i mmune system; probably a diagnosis of essential thrombocytemia is not justified.