Why do children with colds or sore throats often have swollen lymph nodes?

When children contract illnesses such as colds or sore throats, their lymph nodes often swell as a direct result of the body's immune system responding to the infection.12

Lymph nodes act as critical filters within the lymphatic system, where they trap foreign antigens—such as bacteria or viruses—that have entered the body. When these infectious agents reach the nodes, they stimulate the proliferation of lymphocytes, the white blood cells responsible for defending the body. This rapid increase in the number of immune cells, combined with the trapping of microorganisms, causes the nodes to enlarge, a condition known as lymphadenopathy.123

In the case of throat or nasal infections, nearby lymphoid tissues like the tonsils and adenoids may also become inflamed and enlarged as they work to arrest and absorb infectious agents. This process is a normal, protective function of the immune system as it works to neutralize the threat.4251