[Importance of selective immunoglobulin A deficiency].

Selective IgA deficiency is the most common primary immunodeficiency. Little is known about the pathogenetic mechanisms leading to this disease. It is estimated that the incidence of this disease in Spain is 1:163. We report 3 cases diagnosed in Primary Care. Most people with selective IgA deficiency are usually asymptomatic and are diagnosed by chance, but patients with recurrent respiratory infections; gastrointestinal, allergic and autoimmune diseases can be associated with this disease. Although there is no treatment at present, its importance lies in the association with different diseases, such as coeliac disease or idiopathic thrombocytopenic purpura. Another important feature is the risk of anaphylaxis after transfusion, and the possible progression to Common Variable Immunodeficiency. It is important to know the vaccines that we can use due to the risk of disease.