Allergy and Venous Thromboembolism: A casual or causative association

Allergic diseases are very frequent conditions worldwide. The pathogenesis of allergic reactions and venous thromboembolism (VTE) shares several risk factors and predisposing conditions. In particular, the concentration of immunoglobulin E (IgE) is considerably increased in patients with allergic diseases, and this immunoglobulin exert many prothrombotic and antifibrinolytic activities, especially through interaction with mast cells. Therefore, this narrative review is aimed to provide an overview of the current scientific evidence supporting a potential relationship between allergy and the risk of VTE. Although no prospective studies have been published so far, the evidence provided by six large cross-sectional studies and several case reports support the existence of an unquestionable epidemiological association between different allergic diseases (especially atopy, asthma, and celiac disease) and venous thrombosis. Two additional investigations reported that the concentration of IgE might predict the onset of severe complications of pulmonary embolism such as pulmonary infarction and pleural fluid accumulation. Therefore, the existence of a convincing epidemiologic link between allergy and VTE paves the way to future investigations aimed to establish whether the prevention or treatment of allergic diseases might be regarded as an effective measure to lower the risk of VTE.