There are many reasons for the swelling of inguinal lymph nodes in boys, such as malignant tumors, infectious diseases, immune system diseases, etc. It is recommended to consult a doctor in time to make a clear diagnosis as soon as possible. 1. Malignant tumors: such as hematologic diseases, such as leukemia, malignant histiocytosis, lymphoma, etc. It may also be other malignant tumors that metastasize to the inguinal lymph nodes, such as bladder cancer, prostate cancer, colorectal cancer and so on. 2. Infectious diseases: viral infections such as EBV, HIV, etc., bacterial infections such as perianal abscess, inguinal lymph node tuberculosis, cellulitis, etc., fungal infections and so on. 3. Immune system diseases: such as rheumatoid arthritis, connective tissue disease, dry syndrome. You should consult a doctor in time, improve the relevant examination, after a clear diagnosis, follow the doctor’s instructions for standardized treatment.