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Post-Op Infection Timeline: When to Expect Warning Signs

Post-Op Infection Timeline: When to Expect Warning Signs

Infection

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Know when post-op infections start, key symptoms by day, and what warning signs to watch for after surgery

By 

Sustainable Vet Group

Updated on

May 13, 2025

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What Is a Post-Operative Infection?

A post-operative infection, also called a surgical site infection (SSI), happens when bacteria enter the wound after surgery. These infections can develop on the skin, under the surface, or even deeper in the tissues or organs.

There are three main types:

  • Superficial SSIs affect only the skin around the incision.
  • Deep SSIs go into the muscle or tissue layers under the skin.
  • Organ/space SSIs occur in body parts that were operated on, such as joints or the abdomen.

Understanding the timeline of post-op infections is important because symptoms don’t always appear right away. Some signs may show within a few days, while others take a week or more. Knowing when to expect normal healing and when to worry helps you act fast and protect your dog’s health after surgery.

General Timeline of Post-Surgical Infections

Knowing when infections usually appear after surgery helps you catch warning signs early and respond quickly.

0–2 Days After Surgery: Normal Reactions vs. Infection

Right after surgery, it’s normal for your dog to have mild redness, swelling, and warmth around the incision. A slight fever, tiredness, and less appetite may also occur as the body heals. These signs usually settle within 48 hours and are not considered infection unless they get worse.

If the wound stays dry, the skin color improves, and your dog becomes more active each day, healing is likely on track. Watch for sudden changes, not just normal post-op reactions.

3–7 Days After Surgery: First Signs of Infection May Appear

This is the most common window for early infections to appear. Redness that spreads, increased swelling, warmth, or leaking fluid (especially yellow or green) can signal an issue. If your dog starts licking the wound, seems more uncomfortable, or shows a bad odor from the incision, it’s time to call your vet.

Pain that worsens instead of improves is also a red flag. Catching symptoms now can prevent deep infections and keep recovery on track.

7–21 Days After Surgery: Deep Infections Surface

In some dogs, deeper infections appear later and may not be obvious right away. If the incision looks delayed in healing, oozes pus, or becomes painful to the touch, the infection may have spread below the surface.

Fever, loss of energy, or signs like limping after orthopedic surgery could mean a deeper problem.

  • Superficial infections stay near the skin and may resolve faster.
  • Deep or organ/space infections affect muscles, joints, or internal tissues and need more intensive care.

Within 30 Days: Peak Window for Post-Op Infections

The CDC defines post-op infections as those occurring within 30 days of surgery, or within 1 year if an implant (like a bone plate or joint prosthesis) is used.

This period is the most important for monitoring. Daily checks for swelling, warmth, discharge, and changes in behavior can help you act early. Always complete the full antibiotic course, keep the wound clean, and follow all aftercare steps provided by your vet.

1–12 Months: Infections in Implant or Prosthetic Surgeries

In surgeries involving implants, infections can develop months later. These are often harder to detect and may appear as subtle signs like joint stiffness, swelling, or mild pain.

The risk is often due to biofilm, a layer of bacteria that forms on implants and is resistant to antibiotics. In these cases, your vet may need special tests to confirm infection.

If your dog shows unusual limping or swelling long after surgery, especially near the implant site, don’t ignore it.

Long-Term Risk: Late-Onset Infections from Bloodstream Spread

Even long after surgery, an infection elsewhere in the body can reach the surgical site through the bloodstream. This is called a hematogenous infection and can happen months or years later.

For example, dental infections, urinary tract infections, or skin abscesses can carry bacteria through the blood and infect joints or implants.

Dogs with orthopedic implants or joint surgeries should get regular checkups and dental care to lower this risk. Tell your vet if your dog had prior surgery before any new treatments.

How to Track Symptoms Over Time

Tracking your dog’s healing progress helps you spot problems early. A symptom log or recovery journal is a simple way to record daily changes like swelling, redness, appetite, energy, and behavior. Take daily photos of the wound to compare healing and catch subtle changes.

You should also check your dog’s temperature once a day if advised by your vet. A fever may be an early sign of infection. Gently inspect the wound for warmth, odor, discharge, or pain during cleaning.

Call your vet if you notice signs that are getting worse, not better, after 2–3 days. Your notes will help your vet decide whether the infection is superficial or deep, and what treatment steps are needed.

What to Expect at Each Follow-Up Visit

Most dogs have their first post-op check within 7 to 10 days after surgery. During this visit, the vet examines the incision for redness, swelling, discharge, or signs of pain. They also check for proper wound closure, suture condition, and whether healing is on track.

If your dog had implants or orthopedic surgery, follow-up visits may continue for several weeks or months. X-rays or bloodwork may be done to rule out deep infections, especially if there’s limping, stiffness, or delayed healing.

Your vet will ask about any changes at home—such as licking, loss of appetite, or behavior shifts—that could point to a developing infection. These visits are key for spotting issues early and making treatment adjustments before complications arise. Always bring your notes or photos to help with the exam.

When to Seek Immediate Help

Some post-surgery signs mean your dog needs urgent veterinary care, not just routine follow-up. Watch for increased swelling, spreading redness, or thick discharge from the wound, especially if it smells bad. These may signal a deep or fast-spreading infection.

Other red flags include:

  • Fever above 103°F
  • Limping, stiffness, or joint swelling
  • Wound reopening or active bleeding
  • Sudden tiredness, vomiting, or refusal to eat

These are emergency symptoms, especially if they appear quickly or worsen within hours. Don’t wait for the next appointment—call your vet or emergency clinic right away.

On the other hand, mild redness, slight scabbing, or minor licking may be monitored with home care and mentioned at your next check-up. When in doubt, always ask your vet. Early action prevents serious complications and supports a safe recovery.

FAQs

What is the most common time for post-op infections to appear in dogs?

Most post-surgical infections show up within 3 to 7 days after surgery. This is when redness, swelling, or discharge may start. However, some infections can appear later, especially with implants or deep wounds, so it’s important to keep monitoring for up to 30 days or more.

How do I know if it’s healing or getting infected?

Healing wounds improve daily—less swelling, a dry incision, and no strong odor. Infected wounds may show spreading redness, pus, pain, or heat. If your dog seems more tired, licks the wound often, or stops eating, those are warning signs that it could be infected.

Can a post-op infection start after two weeks?

Yes, especially with deeper tissue surgeries or implants. Some infections stay hidden for 1 to 3 weeks or longer. Late signs include swelling, joint pain, or poor healing. Always follow your vet’s full aftercare plan, even if the wound looks fine early on.

Should I clean the surgical wound at home?

Only clean the wound if your vet tells you to. Use vet-approved saline or antiseptic solutions and never apply creams unless advised. Keeping the area dry and protected is often enough. Over-cleaning or using human products can cause irritation or delay healing.

How often should I check the wound?

Check your dog’s wound once or twice a day for signs of redness, discharge, or swelling. Look for any behavior changes, like licking, limping, or pain. Taking daily photos can help you notice small changes and share them easily with your vet.

What should I do if I miss a follow-up appointment?

Call your vet right away to reschedule. Missing a check-up could delay spotting early signs of infection or poor healing. Even if everything looks fine, post-op exams are important for your dog’s recovery and may catch issues before they become serious.

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