Lymphadenopathy refers to the swelling or enlargement of lymph nodes, which are small, bean-shaped structures that play a crucial role in the immune system. This condition can occur in one area of the body or multiple regions and may be a response to infections, inflammation, or other medical conditions. Common causes of lymphadenopathy include viral infections like influenza, bacterial infections such as strep throat, and more serious conditions like lymphoma or leukemia. Diagnosis typically involves a physical examination, medical history, and sometimes imaging or biopsy to determine the underlying cause.