Why is there a painful lump in my armpit post-flu shot?

Hi,

Welcome to icliniq.com.

I understand your concern. You are having lymph node swelling axillary post influenza vaccination. Influenza vaccine is a very safe vaccine. Although some may have local pain, swelling, and fever. Some may have local lymphadenopathy.

Lymphadenopathy is a swelling of lymph node (normal gland present in our body, which function as clearing harmful substances and providing immunity). Local and systemic reactions mostly began between day 1 and day 2.

When a lymph node rapidly increases in size, its capsule stretches and causes pain. Pain is usually the result of an inflammatory process. It is a reactive response of the lymph node to the vaccination. So no need to worry.

It can be managed by simple Paracetamol or anti-inflammatory medication such as Serratiopeptidase. It should resolve within a week. If it is associated with fever or any other site enlargement of lymph node you can visit your physician.

I hope this helps.