Factors That Contribute to the Risk of Recurrent Infections

Children presenting with a history of recurrent or unusual infections pose a diagnostic and management challenge. Although immune deficiency diseases are relatively uncommon in the general population, it is important for clinicians to be able to recognize and evaluate patients for these diseases. Historically, there has been a significant delay from onset of recurrent infections to diagnosis of underlying immune deficiency. Although progress has been made in decreasing the delay in diagnosis overall in the population of patients with immune deficiency diseases, it is important to maintain a high index of suspicion for primary immune deficiency to ensure timely diagnosis and treatment. Evaluation of a patient with frequent infections requires a careful history and physical examination directed at identifying common risk factors for infection versus finding clues that may help identify and categorize potential underlying immune deficiency. The medical history is important for determining whether there are potential risk factors (e.g., passive smoke exposure, daycare attendance, atopy, anatomic defects) for frequent infections. In contrast, immune deficiency should be suspected when recurrent infections are either severe, resistant to treatment, or caused by unusual organisms or there is a family history of recurrent infection. This chapter presents an approach to the evaluation of children with recurrent infections, including an overview of the pertinent history, noninfectious manifestations, physical examination findings, and targeted laboratory evaluation for disorders of innate immunity, humoral immunity, and cellular immunity.