Many diseases can cause swollen preauricular lymph nodes, and local tissue or organ infection is one of the most common factors, such as lymphadenitis, blepharitis, otitis media, gingivitis, parotitis, tonsillitis, etc.
In addition, other non-infectious diseases such as lymphoma, leukemia, nasopharyngeal carcinoma, systemic lupus erythematosus, nodular disease, etc. should also be excluded to avoid delaying treatment. If multiple lymph nodes throughout the body are swollen, the possibility of lymphoma is highly suspected and a lymph node biopsy is needed for a clear diagnosis if necessary.