Wound healing

Wound healing is the body’s own repair process in which damaged skin and tissue grow together again. In dogs, this process is frequently disrupted by the instinctive urge to lick.

Unlike in humans, it is not the wound that is the focus of attention in dogs, but the urge to clean it. The impulse is natural, but it can delay or even completely interrupt the healing process.

How does wound healing work in dogs?

Dog wounds go through three clearly distinguishable phases. In the first one to three days after the injury, the inflammatory response sets in: blood clots, the area swells and becomes warm. White blood cells clear away bacteria and tissue debris.

From the second to fourth day, the building phase begins, which lasts up to three weeks. New connective tissue fills the wound, tiny blood vessels sprout and the wound edges slowly draw together. The typical reddish granulation forms, a sign of healthy healing.

In the final remodelling phase, which lasts weeks to months, the new tissue solidifies. Collagen fibres rearrange themselves and the scar becomes more stable. It takes time: after two weeks, the suture only withstands 5 to 10 per cent of what uninjured skin bears; after three to four weeks, around a quarter. The scar only reaches its final strength after months; remodelling continues for up to two years – and even then it remains 15 to 20 per cent weaker than the original skin.

What makes dog wounds different from human wounds?

Dog saliva does contain antibacterial enzymes, but its moisture damages the forming tissue. A dog that licks its wound keeps it permanently moist, which slows down healing.

Then there is the fur problem: hairs that get into the wound act like foreign bodies and can trigger inflammation. In some breeds, the fur grows back so densely that it literally closes off the wound before it has healed from the inside.

Dog skin is also thinner than human skin and tears open more easily if the dog scratches or rubs the area against objects.

Which wounds heal problematically?

Bite wounds from other dogs carry the greatest risk of infection. The bacteria from the dog’s mouth penetrate deep into the tissue and can form abscesses there. Superficially small bite wounds often disguise the depth of the injury.

Paw injuries heal poorly due to constant strain. Every step stretches the forming tissue and can tear it open again. Cuts on elbows or other joint areas have the same problem.

Surgical wounds are created under sterile conditions, but precisely the suture sites tempt dogs to lick intensively. A burst surgical suture often requires a second procedure.

How do you recognise healing disorders?

A healthy wound smells neutral and secretes at most clear or slightly yellowish fluid. Purulent, foul-smelling secretions indicate an infection. The wound edges should slowly come together, not gape open.

Excessive swelling that does not subside after the first few days is a warning sign. Normal wound healing causes local warmth, but if the heat spreads or the dog develops a fever, something is going wrong.

Some dogs become inappetent or unusually tired with wound infections. Such systemic signs are more serious than local symptoms and require immediate veterinary treatment.

What supports healing?

The most important factor is preventing licking and scratching. A protective collar may look uncomfortable, but it significantly accelerates healing. Some dogs get used to body suits or special bandages that are more comfortable.

Protein-rich nutrition provides the building blocks for new tissue. Wound healing costs protein – however, how much more a dog needs for this is not quantified. The feeding recommendation for wound patients states a target value, not an increase: 4 to 6 grams of protein per 100 kilocalories, whereas normal maintenance feeding already lies at approximately 4.5 to 5.2 grams. Therefore, what is more important than a percentage figure is that the dog eats at all. Vitamin C and zinc can support collagen formation, but you should only use dietary supplements after consulting your vet.

Rest is crucial, especially with joint wounds. A normally active dog may have to walk on a short lead for weeks. This is frustrating, but it prevents the wound from reopening.

When does it become serious?

Heavy bleeding that cannot be stopped with direct pressure is an emergency. Deep wounds, where fat or muscles are visible, also require immediate veterinary treatment.

You should always have bite wounds examined by a vet, even if they look superficial. The puncture sites can reach deep and trap bacteria. Contaminated wounds with soil, glass or other foreign bodies require professional cleaning.

If a wound shows no signs of healing after a week or even worsens, something is wrong with the healing process. Diabetes, immunodeficiency or circulatory disorders may be behind it.