Pets for studWanted petsBreeders

Accessories & services

Knowledge hub


Support & safety portal
Pets for saleAll Pets for sale
Recognising the symptoms of infections in dogs

Recognising the symptoms of infections in dogs

Health & Safety

Unlike cats, dogs generally make it quite clear to their owners when something is wrong with them, and they are not as likely to try to mask pain or discomfort, or try to hide away out of sight. However, because dogs can’t tell us what is wrong when they feel unwell, it is up to us as dog owners to learn to recognise the common signs of illness and discomfort in dogs, so that we can get them the appropriate veterinary care when they need it.

One of the most common illnesses that dogs face, and one that will affect a large proportion of the canine community at some point is infection, which may be either external or internal. Infections can be viral, fungal or bacterial (or several other less-common variants too), and generate a range of both direct and systemic symptoms in your dog if they succumb to an infection.

In this article, we will look at how to recognise the symptoms of infections in dogs, so that you can act quickly when warranted to contact your vet and begin treatment. Read on to learn more.

What is an infection?

An infection is what occurs when your dog’s body is invaded by an agent (like a bacteria or virus) that causes disease, and the response that the body generates as a result of this invasion. Many of the common symptoms of infections actually occur as a result of the body’s immune system swinging into action to attack the invader – such as the production of pus from a wound.

Pus is the result of the large-scale destruction of white blood cells, which are sent to fight the attacking agent, rather than due to the agent in question itself.

Many infections will be mild and clear up on their own as your dog’s immune system works to defend the body – but others can be more serious and have a significant impact on your dog’s health, even in some cases, proving fatal.

How do dogs get infections?

Dogs can develop infections in a huge variety of different ways, but the basic principle of infection transmission involves the presence of an infective agent (such as a harmful virus or bacteria) and the introduction of this into the body.

For instance, cuts and grazes might result in an infection because the damage to the skin allows potential contaminants to enter the wound, and multiply within the body. However, dogs come into contact with potentially harmful viral agents and bacteria every day without any problems, because their immune systems fight off the potential attacker before it is able to multiply.

Infections can also occur inside of the body, based on the same principles; for instance, a dog that suffers from persistent kidney stones will be more at risk of UTI’s and kidney infections, due to the resultant weakness and potential damage that ensues.

Dogs with weakened immune systems, young puppies with low natural immunity and that have not been vaccinated, and older dogs are at greater risk of developing infections that others.

External infection symptoms in dogs

External infections are those that occur on the outside of the body where you can see them – such as at the site of a wound or surgical incision.

Correctly diagnosing an external infection is easier than diagnosing an internal infection, because you can see what is going on!

If your dog has a healing wound or graze, or a surgical incision that is healing, it is important to keep a close eye on the healing process to reduce the chances of infection, and in order to spot a developing infection quickly.

Some of the symptoms of an external infections include:

  • Hot, inflamed skin in the area in question.
  • Redness and soreness.
  • Pain in the local area, which may make your dog very sensitive to attempts to touch the affected area.
  • Further wound breakdown or the reversal of any previous healing.
  • A discharge of pus, or in some cases, the build-up of pus under the skin, which can result in an abscess or cellulitis.
  • Infected wounds will often smell foul.
  • A properly healing wound will improve day by day; a wound that is infected or compromised will worsen.
  • External infections will also generally generate internal, systemic symptoms too, which we will look at in the next section. More information about the discharge and different ear wax colours you can find in this article.

Internal infection symptoms in dogs

If your dog has an internal infection, this can be much harder to recognise as the symptoms are more general, and cannot be assigned to a specific and obvious wound.

However, internal infections will still produce a range of clear symptoms within your dog, and so the trick is learning to recognise them and understand what they mean.

Some of the systemic symptoms of infections that can occur for both internal and external infections in dogs are:

  • Running a fever and feeling hot.
  • Losing interest in food or refusing to eat.
  • Lethargy and loss of interest in play and exercise.
  • Potentially, physical signs of internal discomfort, such as showing signs of pain if you touch a certain area of the body.
  • A dog with an internal infection will often feel quite ill, which can result in behavioural changes such as snappishness and defensive aggression.
  • Some types of internal infections will also generate external symptoms, such as a pus discharge from the vulva in the case of some (but not all) pyometra infections, or a discharge from the eyes in the case of conjunctivitis.

If you think that your dog has an infection or are otherwise concerned about any symptoms they may be developing, speak to your vet immediately so that they can intervene promptly and help your dog to recover.