Secondary Immunodeficiency.

The field of medicine is constantly changing and, as healthcare providers, we are fortunate to be practicing in a time when patients are living longer and novel therapeutic options continue to evolve. However, these new advances may be associated with adverse effects that practitioners need to be aware of. Some of these impair the immune system leading to secondary immunodeficiencies (SID) that increase host susceptibility to infections and other complications. The causes and consequences of these SID are extremely broad, and a detailed review is beyond the scope of this article. The goal of this primer is to provide a general overview and understanding of common conditions and therapies leading to SID, as well as a guide to the assessment and management of patients with SID.