Infection after surgery: signs, timing and when to call

A surgical site infection is one of the most common complications after an operation. Most are minor and respond well to treatment when they are caught early. The key is knowing what normal healing looks like, and which changes should be reported without waiting for the next appointment.

When does an infection usually appear?

Most wound infections show up between the 3rd and the 10th day after surgery, often once the patient is already back home. They can appear up to 30 days after the operation, and up to a year when an implant was placed (joint replacement, mesh, breast implant). This is why the days after discharge are the ones that need the closest attention.

Normal healing: what you can expect

• A thin pink or red line along the edges of the incision during the first days.
• Mild swelling and tenderness around the wound, decreasing day after day.
• A small amount of clear or slightly pink fluid in the first 48 hours.
• Some itching as the skin heals.
• Pain that gradually improves and is relieved by the prescribed medication.

Signs of infection to report the same day

• Redness that spreads beyond the edges of the wound, or a red streak moving away from it.
• Increasing warmth, swelling or hardness around the incision.
• Pain at the wound that gets worse after the first days instead of better.
• Cloudy, yellow or green discharge, pus, or a bad smell.
• Wound edges that open or separate.
• A fever above 38 °C (100.4 °F), especially if it appears after the 3rd day.

When it is an emergency

• Redness that spreads quickly over a few hours, or skin that turns dark or purple.
• High fever above 39 °C (102.2 °F) with chills or shivering.
• Confusion, severe drowsiness, a racing heart or difficulty breathing.
• After abdominal surgery: abdominal pain that is getting worse, a hard belly, or repeated vomiting.

Who is more at risk?

Anyone can develop a wound infection, but the risk is higher in people who smoke, have diabetes that is not well controlled, are overweight, take treatments that lower immunity, or have had a long or emergency operation. Surgery on the bowel also carries a higher risk than surgery on clean skin.

How to lower the risk at home

• Wash your hands before and after touching the dressing, and follow your team's instructions on when and how to change it.
• Keep the wound clean and dry; don't take baths, swim or use a hot tub until your surgeon allows it.
• Don't apply creams, powders or home remedies to the incision unless they were prescribed.
• Don't smoke during healing, and keep your blood sugar under control if you have diabetes.
• Never start leftover antibiotics on your own: if an infection is suspected, your surgeon decides on the treatment.

How an infection is treated

Treatment depends on how deep the infection is. A superficial infection is often treated with wound care and sometimes antibiotics. A deeper infection may require opening and cleaning the wound, or a new procedure. In all cases, the earlier it is reported, the simpler the treatment usually is.

Why daily follow-up helps catch it early

An infection rarely starts on the day of a scheduled visit. It often begins with small changes — a little more redness, a bit more pain, a low temperature on day 5 — that are easy to dismiss. With Melav, patients answer a short check-in by SMS at each step after surgery: when they report a priority warning sign, they immediately get a fixed instruction validated by their surgeon, and the surgeon receives an SMS alert within seconds.