Signs of Dog Wound Infections [With Pics & Vet Explanations]

Whether your dog gets into a fight resulting in a wound, tears a toenail, or has a surgical procedure performed by your vet, it’s important for pet parents to know how to monitor wound healing and watch for signs of infection. A wound is defined as damage to living tissue, whether from a cut, break, burn, or tear, and we see them every day in veterinary practice. 

Wounds can either be clean (created in a sterile procedure such as a surgery) or dirty/contaminated (an injury from a dog bite for example). If a significant number of bacteria are present, the wound will become infected. Wounds and wound infections range from mild to life threatening, depending on many factors, such as the type, size, and location of wound, and the health of your dog.  

How can I know for sure if my dog’s wound is infected, or if it’s just healing?

If your dog has a wound, you will want to monitor it daily to watch for changes and signs of infection. 

• Redness – While slight redness to the area of a wound can be normal, excessive redness, redness that appears suddenly, or red streaks around a wound are causes for concern. 
• Swelling – Swelling is also part of the healing process, however excessive swelling or an increase in swelling should be brought to your vet’s attention.
• Heat – Another sign of inflammation or infection is warmth coming from the area of the wound. 
• Pus – Purulent discharge from a wound that is white, green, or yellow is also a sign of infection.  
• Pain – Wounds hurt, but pain should improve throughout the healing process. If there is an increase in pain, it may indicate that an infection is brewing. 
• Dehisence (re-opening of the wound) – A wound should not re-open after it has been closed or healed.  
• Foul smell – Another clear sign of infection is a foul odor coming from the wound. 
• Non-healing wound – If a wound is not healing or partly heals then recurs, it may indicate a more serious underlying issue. 
• Systemic signs – Depending on the severity of the infection, some dogs may develop other signs of illness, such as fever, lethargy, and decreased appetite. 

Some degree of redness, swelling, bruising, scabbing, and tenderness is to be expected during the healing process, however, if you have any concerns that a wound is not healing properly, it is important to contact your veterinarian as soon as possible. Additional treatments will likely be needed to address an infected wound. 

The time it takes a wound to heal will vary greatly. Small wounds may heal within a couple days, most surgical incisions take 10-14 days to heal, and larger wounds may take months to fully resolve. Below are examples of pictures of normal and infected wounds. 

What a normal healing wound looks like in dogs [with pictures]

These images show a normal progression of healing after a spay surgery:

Day 1-2:

Day 4-5:

Day 8-10:

Another example of normal healing after a surgery. A small amount of redness and scabbing is expected. 

This is an example of granulation tissue. While this picture may look concerning to many pet parents, it actually depicts the healthy pink tissue that fills in a wound. Over time the wound will continue to contract and shrink in size. 

What a wound infection looks like [with pictures]

In the picture below, you can see the difference between an inflamed and infected wound (left), in contrast to a normal healing area (right). On the left, the skin is red and irritated as a result of the dog licking the wound excessively:

This dog’s abdominal incision is very inflamed. It has been closed with staples that are becoming embedded due to the swelling of the skin:

Below is a picture of an incision that is very clearly infected, with a green discharge and significant swelling:

Pictured below is a surgery incision that is now very inflamed / red and has discharge:

You can view more pictures in our article about incision infections in dogs and more specifically spay incision infections.

How wounds heal

The four stages of wound healing in dogs

Wounds heal in four stages which are summarized below (terminology may differ slightly between vets). Wound healing can be influenced by factors such as your dog’s overall health, any medications they may be taking, the type of wound, the location of the wound, and the environment. 

1. Inflammation – The first stage of wound healing begins immediately and focuses on stopping bleeding and activating the immune system to help “clean up” bacteria and damaged tissue. Blood clots form and white blood cells get to work. 
2. Debridement – Within a few hours, pus is formed from dead tissue, wound fluid, and immunologic cells. This flows from the wound, taking debris with it. The body is working on cleaning the area. 
3. Repair – After a couple days, collagen beings to fill in the wound and new blood vessels begin to form. Fresh pink granulation tissue is produced from the wound edges and the size of the wound begins to shrink. 
4. Maturation – This process begins several weeks after a wound and may continue for weeks, months, or years. Collagen is reorganized and blood vessels and nerves continue to regenerate, helping to form and strengthen a scar. Scar tissue will never be as strong as uninjured tissue. 

See here for more information and pictures of wound healing stages in dogs. 

Primary intention versus secondary intention wound healing 

Wounds can heal by primary or secondary intention. If the edges of a wound are apposed (touching each other) and closed with sutures, this is known as primary intention healing. The edges simply have to bond together and fill in the small gap between them with new skin. This process takes approximately 10-14 days. An example of this type of wound healing is a surgical incision. 

If a wound is too big to close or is infected, it will be left open to heal via second intention. Granulation tissue will form over the wound, and then the edges of the wound will gradually contract and come together. This process may take much longer. The wound may be left open or covered with special types of bandages to promote healing. 

What causes wound infections

Wound infections occur when bacteria colonize a wound. This may happen for several reasons. To help prevent infection from developing be sure to follow your veterinarian’s advice in terms of activity level during healing, medications, follow-up appointments, and use of an E collar or other products.  

• Dirty or contaminated wound – Wounds caused by bites, penetrating trauma, or those that have been contaminated by the environment are more likely to become infected, as bacteria and dirt are introduced into the wound. Bite wounds especially may cause significant damage to underlying tissues, which can affect healing. 
• Size and location of the wound – Wounds around the genital area may easily be contaminated with feces, while wounds in high-motion areas (such as the armpit) may have difficulty healing. Wounds covering larger areas of the body are at higher risk. 
• Licking or scratching – Chewing, licking, rubbing, or scratching at a wound will delay healing and is a leading cause of wound infection in dogs. Be sure to keep an E collar on your dog at all times when unsupervised. 
• Pre-existing skin disease – If a dog already has a skin infection (due to allergies for example), they are more likely to develop a wound infection in that area. 
• Poor aseptic technique – If there is a breach of sterility during surgery (for example use of nonsteralized instruments or a tear in a surgical glove), an infection may develop. In these situations, your veterinarian may recommend prophylactic antibiotics. 
• Underlying disease – Dogs with immunosuppression from underlying disease, cancer, or chronic use of steroids may also be predisposed to unhealing or infected wounds. 

When to call your veterinarian about a wound concern

If you notice signs of infection associated with your dog’s surgical incision or wound, it is important to contact your vet right away. Signs of infection include pain, redness, swelling, heat, purulent discharge, foul odor, and other systemic signs of illness. However, it is best to have your dog evalauted immediately after they are wounded. This way your vet will be able assess the damage and come up with a treatment plan to help prevent infection from developing in the first place. 

How are wound infections treated? 

Steps you can take at home to help wounds heal better?

If a wound becomes infected it will require veterinary treatment, and quickly so that the infection does not continue to spread. The following steps can be taken to help prevent infection and while waiting for your veterinary appointment. 

• E collar – It is imperative to prevent your dog from licking, chewing, or scratching at a wound. Depending on the location of the wound, you may use an E collar or a loose t-shirt to help protect the area. If the wound is on a limb, do not attempt to bandage it – bandages that are too tight can cause further damage. 
• Clip and clean – For small or mild wounds, if your dog allows, you may clip the fur and gently clean the wound with sterile saline or warm water and soap. If you do not have clippers, washing the wound to remove larger particles of debris and dirt will still be beneficial. 
• Follow your vet’s advice – For healing surgical incisions, be sure to follow your vet’s discharge instructions. It is important to restrict exercise for approximately two weeks and keep the area clean and dry. Do not apply topical ointment to a surgical incision unless directed by your vet. 

Veterinary treatment for wound infections

Treatment of wound infection may vary based on the type, severity, and location of the wound. However, your vet may recommend some of the following: 

• Address major trauma and severe injuries – In the case of severe wounds (for example gun shot or hit by car), your dog may have more severe injuries or be in shock, which will need to be addressed first. 
• Cleaning the wound –  As dogs are furry creatures, a wound will need to be clipped and flushed with a product such as sterile saline. Your vet may recommend doing this under sedation or anesthesia.
• Bacterial culture – In some cases, your vet may recommend obtaining a sample from the wound for a culture. This will allow them to grow any bacteria that are present, and determine which antibiotics it will respond to. 
• Bloodwork – If surgery is indicated, bloodwork to help evaluate your dog’s overall health and major organ function is usually indicated. 
• Surgery – This will vary depending on the type of wound. If a wound is deep, your vet may recommend closing it with sutures, as long as it appears clean. If a wound is dirty or infected, it should not be closed and must be managed as an open wound or closed after infection has resolved. In some cases, surgery is needed to remove diseased tissue so that healthy skin can be stitched together. Large pockets of pus should be removed, and in some cases a drain may be placed. In severe cases, you may be referred to a specialist for surgical procedures such as skin grafts. 
• Antibiotics – Antibiotics are used to treat bacterial infections, including wound infections. This may include oral medications (pills, capsules, or liquid) and/or topical medications. 
• Anti-inflammatories – In many cases, this will be recommended to help address pain and inflammation associated with a wound infection. 
• Topical products – Topical products containing antibiotics (ointments, wipes, sprays) may be applied to some wounds to help treat infection, keep the wound moist, and promote healing. Your veterinarian may also recommend other types of products. In rare cases, your vet may recommend use of a human product. Do not apply anything to a wound without first consulting your vet. 
• Bandage – Sometimes a bandage will be placed to protect or help manage a wound. 

Frequently asked questions

Can you put human OTC medication on a dog wound – for example Neosporin?

In a pinch, Neosporin may be used on small or mild wounds in dogs. Be sure that this product does not get in the eyes, nose, or mouth. Before applying this product, you should clip the fur away from the wound and clean it with sterile saline or warm water and soap. When possible, it is always better to use a dog-specific product from your vet, which will be safer and more effective.