Immunodeficiency Syndromes

Primary immunodeficiency syndromes represent a heterogeneous group of disorders characterized by increased susceptibility to infection, often together with additional features such as autoimmunity, allergy and malignancy. The molecular bases have been defined for more than 130 monogenic primary immunodeficiency diseases, providing valuable insight into the function of the immune system. Immunodeficiency should be suspected when children have recurrent infections of increased duration and severity, with a poor response to treatment, or caused by unusual organisms. Immunodeficiency syndromes are often associated with prominent mucocutaneous abnormalities, which can facilitate early diagnosis. In addition to mucocutaneous infections (most often caused by Staphylococcus aureus, Candida spp. and human papilloma viruses), non-infectious mucocutaneous features that are shared by several immunodeficiency syndromes include granulomas, eczematous dermatitis, lupus erythematosus-like lesions, small-vessel vasculitis, and ulcers. Other skin findings in patients with recurrent infections may point to a specific underlying diagnosis.