Lymph node infected

Hi,
I recently found a lump in my left breast and went to the doctor for a mammogram and ultrasound. The doctor says it is an infected lymph node. I have went through one round of antibiotics, but it is still there. I am starting to have pain in the left part of my neck, but I am not sure if the two are related. They are going to put me on another antibiotic. My question is, how many antiboitics will I have to be on before it is gone or is this something to be concerned about?Also, can an infected lymph node be cancer? What exactly would the test I took show?

[Dennis MD]

Hi.
Enlargement of lymph nodes are usually secondary to an infection near the area of the draining lymph nodes.  Antibiotics will control the infection.  But usually the enlarged lymph nodes will still remain enlarged or will only decrease in size after an intake of antibiotic.  Other cause of enlarged lymph nodes includes malignancy like metastatic carcinoma or lymphoma.  A lymph node secondary to cancer may become secondarily infected.
You may continue with your second course of antibiotic.  You may also request for a biopsy to be more definite.  A biopsy can tell whether the lymph node enlargement is secondary to an infection or to something else.
Take care.