Symptoms vs Signs in Pets

Symptoms vs Signs in Pets

By Dr Duncan Houston

Quick Answer

Humans describe symptoms, which are things they feel, like pain or nausea. Pets cannot tell us that directly, so in veterinary medicine we rely on signs, which are things we can observe, measure, or report, such as vomiting, limping, coughing, or changes in appetite.

As a veterinarian, this distinction matters a lot. Your pet cannot say, “My stomach hurts” or “My vision feels weird.” They show us clues instead.

When people get sick, they can usually explain what they are feeling. They can point to where it hurts, describe the pain, and tell a doctor when it started.

Pets do not have that option.

That means veterinary medicine relies heavily on observation. We piece together what might be wrong based on what owners notice at home, what we see during the exam, and what tests tell us.

What Is a Symptom?

A symptom is something a patient experiences and reports.

In human medicine, symptoms can include:

• Pain

• Nausea

• Dizziness

• Fatigue

• Headache

• Feeling hot or cold

These are subjective experiences. They matter, but they depend on the patient being able to describe them.

Your dog cannot tell me they feel nauseous. Your cat is definitely not filling out a pain questionnaire. That would save all of us time, but sadly no.

What Is a Sign?

A sign is something that can be observed, measured, or detected by someone else.

In pets, signs can include:

• Vomiting

• Diarrhoea

• Limping

• Coughing

• Sneezing

• Bleeding

• Weight loss

• Increased drinking

• Increased urination

• Lethargy

• Swelling

• Discharge from the eyes, nose, or ears

These are the things that help us work out what may be going on.

In veterinary medicine, signs are often the closest equivalent we have to symptoms.

Why This Matters in Pets

Because pets cannot explain how they feel, small changes become very important.

A veterinarian often depends on the owner to notice:

• What changed

• When it started

• How often it happens

• Whether it is getting better or worse

• Whether anything triggered it

This is why an observant owner is incredibly valuable.

Sometimes the only early clue of illness is something subtle, like:

• Sleeping more than usual

• Not finishing meals

• Hiding more

• Being less playful

• Jumping less often

• Drinking more water

These changes can sound minor, but medically they can be very useful.

Common Signs Owners Notice at Home

Some of the most important signs to watch for include:

Changes in appetite

Eating less, eating more slowly, refusing food, or suddenly becoming very hungry

Changes in thirst

Drinking noticeably more or less than usual

Vomiting or diarrhoea

Even if it seems mild at first

Limping or stiffness

Especially if it keeps happening or gets worse

Lethargy

Less energy, more sleeping, or reduced interest in normal activities

Behaviour changes

Hiding, clinginess, irritability, confusion, or unusual aggression

Toileting changes

Urinating more often, struggling to urinate, accidents in the house, constipation, or diarrhoea

Breathing changes

Panting at rest, coughing, noisy breathing, or increased breathing effort

These are not diagnoses. They are clues.

Example: Limping

Limping is a good example of why signs matter.

A person with a sore leg might say:

• “My ankle hurts”

• “It feels swollen”

• “It started after I twisted it”

A dog cannot tell us that.

If your dog is limping, the cause could be:

• A paw injury

• A cracked nail

• A thorn or grass seed

• A sprain

• A fracture

• Arthritis

• A ligament injury

• An insect sting

• A joint problem

To narrow it down, your vet relies on the signs you report.

Helpful details include:

• When the limp started

• Whether it was sudden or gradual

• Whether it is constant or comes and goes

• Which leg seems affected

• Whether it is worse after rest or exercise

• Whether your dog licked the paw or cried out

That information can make a big difference.

What to Tell Your Vet

When something is wrong, try to give your vet clear details rather than just saying your pet is “not okay.”

Useful things to report include:

• When it started

• How often it happens

• Whether it is getting better, worse, or staying the same

• Any changes in food, environment, medication, or routine

• Whether there are any other signs happening at the same time

For example, “My cat vomited twice this morning and is now hiding under the bed” is much more useful than “My cat seems sick.”

Videos and photos can also be incredibly helpful, especially for:

• Limping

• Coughing

• Seizure-like episodes

• Collapse

• Abnormal breathing

• Behaviour changes that are hard to reproduce in clinic

Pets have a funny habit of acting completely normal the moment they arrive at the vet, just to keep things interesting.

Behaviour Is a Sign Too

Owners sometimes overlook behaviour changes because they do not look like “medical” problems.

But behaviour can be one of the earliest signs of illness or pain.

Examples include:

• A normally social cat hiding away

• A friendly dog becoming snappy when touched

• A pet no longer jumping onto furniture

• Restlessness at night

• Confusion or staring into space

• House soiling in a previously trained pet

These are important and worth mentioning.

Why Early Signs Matter

The earlier a problem is recognised, the easier it often is to treat.

Waiting until something becomes dramatic can mean:

• More suffering for the pet

• More complicated treatment

• Higher costs

• Fewer treatment options

Owners sometimes worry about “overreacting,” but in many cases it is better to ask early than wait too long.

You do not need to identify the diagnosis. You just need to notice the change.

Final Thoughts

In veterinary medicine, pets do not tell us symptoms in words. They show us signs through changes in movement, behaviour, appetite, breathing, toileting, and routine.

That is why your observations matter so much.

If something feels off, even if you cannot fully explain it, pay attention. Subtle signs are often where diagnosis begins.

FAQ

What is the difference between a symptom and a sign in pets?

A symptom is something a patient feels and describes. A sign is something that can be observed, measured, or reported by someone else.

Can pets have symptoms?

They likely experience things like pain or nausea, but because they cannot describe them directly, vets rely on observable signs instead.

What signs should I report to my vet?

Changes in appetite, thirst, movement, breathing, toileting, behaviour, vomiting, diarrhoea, coughing, or anything else unusual.

Should I mention small changes?

Yes. Small changes can sometimes be the earliest clue that something is wrong.

Not Sure Whether What You’re Seeing Matters?

The ASK A VET™ app can help you track your pet’s signs, store health information, and get guidance when you are not sure whether a change is minor, meaningful, or something that needs prompt veterinary attention.