Atopic dermatitis and allergic diseases with thrombocytosis: a possible link

BACKGROUND: Thrombocytosis can be present in patients with myeloproliferative disorders or can accompany various conditions, in particular chronic inflammatory diseases, namely chronic bowel diseases, rheumatoid 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 thrombocytemia in agreement with polycytemia vera study group criteria and 22 by reactive thrombocytosis. Serotonin concentration has been determine in all the patients. RESULTS: Serotonin was decreased as expected in 23 out of the 33 patients with essential thrombocytemia. In the remaining ten subjects, serotonin was within normal limits as in reactive thrombocytosis. Eight of these subjects had positive histories for allergic rhinitis and two for atopic dermatitis. CONCLUSIONS: Chronic inflammation, present in patients with diseases of the immune system may cause an increased platelet number. One should consider with caution patients with thrombocytosis and positive histories for diseases of the immune system; probably a diagnosis of essential thrombocytemia is not justified