In adults, recurrent infections are usually due to an anatomic lesion or to a secondary cause of immune suppression, although primary immunodeficiencies are also in the differential diagnosis.
Anatomic lesions, whether congenital or acquired, are an important cause of recurrent infections in adults.
Secondary immune disorders due to other medical conditions or treatments for these conditions are a much more common cause of recurrent infections than primary immunodeficiencies.
Secondary immune disorders are far more prevalent than primary immunodeficiencies and should be considered in the presence of underlying disease states, medications, or previous surgical procedures:
- Diabetes mellitus
- Peripheral arterial disease with ischemia
- HIV infection
- Cirrhosis
- Nephrotic syndrome
- Hemoglobinopathy
- Inflammatory bowel disease
- Neurologic disease
- Autoimmune disease
- Splenectomy
- Malignancy
- Radiation therapy
- Immunosuppressive agents, such as glucocorticoids and others
- Immunomodulatory agents, such as rituximab, etanercept, and others