Old incision re-opening by itself

Dear Ask The Doctor: I am a 34 year old female that had a c-section 4 years ago. I have recently gained a large amount of weight and have hypothyroidism. I found a 2mm hole in my old incision and it has a bloody, foul smelling discharge. What could have caused this?

Dear Chris: It seems you have developed a infection in your c-section scar. You will require a course of antibiotics after the infection is confirmed with the appropriate test by your doctor. The infection could have been caused by the presence of a foreign body in the scar such as a suture (stitch). This can be verified when you go to see your doctor to treat your infection.