Common Diseases in Dogs: How to Prevent and Detect Them Early

by Karina Caribana September 15, 2026

Obesity, otitis, hip dysplasia, periodontal disease and dermatitis. Five health problems that affect millions of dogs every year and that, in a great many cases, could have been prevented or detected much earlier. The key is not to become veterinarians, but to develop that everyday "clinical eye" that turns an attentive owner into their dog's best early warning system.

The good news: most of these diseases give warning. They send small signals — a change in weight, a smell in the ears, less desire to play — that, if you learn to read them, give you weeks or months of advantage. In this guide we review the five most common conditions, how to recognise them in time and what to do to prevent them.

Prevention as the best investment in your dog's health

An annual veterinary check-up costs a fraction of what it costs to treat an advanced chronic disease. And we don't say that only in economic terms: a dog that maintains a healthy weight, clean teeth, dry ears and well-cared-for joints lives, on average, between 1.5 and 2.5 years longer than one that carries these problems without control.

Prevention is based on three simple pillars:

Daily observation: 60 seconds a day checking the eyes, ears, mouth, skin and gait.
Weight and feeding control: the most powerful and most overlooked tool.
Regular veterinary check-ups: not only when something hurts.

Obesity: the silent epidemic that shortens your dog's life

More than half of companion dogs are overweight or obese. It is easy to overlook because it sets in little by little, and because a "chubby" dog seems cute to us. But obesity is not cosmetic: it is a direct risk factor for diabetes, joint problems, and heart and respiratory diseases.

How to assess body condition

You don't need a scale to start. Use the body condition score (1-9) with your hands:

Score	Condition	What it feels like to the touch
1-3	Underweight	Ribs, spine and hip bones very visible; no fat
4-5	Ideal	Ribs easily palpable, waist visible from above, tucked abdomen
6-7	Overweight	Ribs difficult to palpate, no clear waist, some accumulated fat
8-9	Obese	Ribs not palpable, obvious fat on the back and base of the tail, sagging abdomen

If your dog is at 6-9, there is room to act. The realistic goal is to lose 1-2% of body weight per week, never more.

Action plan

Measure the food. The "eye" deceives: use a measuring cup and weigh the portion at least once a month.
Reduce treats to 10% of daily calories. A carrot or a piece of apple counts the same as a treat.
Increase exercise gradually. From 10 minutes go to 20, then to 30. An obese dog should not run all at once.
Check with your veterinarian before starting any reduction diet.

Otitis: when the ears speak

Otitis (inflammation of the ear canal) is one of the most frequent veterinary consultations. It can be external, middle or internal, and if it becomes chronic it turns into a recurring and painful problem.

Causes and predisposed breeds

Causes: moisture, fungi (Malassezia), bacteria, mites, allergies or foreign bodies (grass awns).
Breeds at risk: those with droopy ears and a narrow canal, such as Cocker Spaniel, Basset Hound, Bulldog, Beagle, Golden Retriever and Labrador, as well as dogs that swim frequently.

Warning signs

Frequent head shaking or persistent head tilt.
Intense scratching of the ear or rubbing it against the floor.
Bad smell, redness or discharge (waxy, brown or with pus).
Pain when touching the ear or loss of balance.

Correct cleaning and when to go to the veterinarian

Use a specific ear cleaner, never alcohol or hydrogen peroxide.
Apply the product into the canal and gently massage the base of the ear.
Let the dog shake its head and clean only what comes out with a gauze.
Never insert cotton swabs inside the canal: they push the dirt inward.

Go to the veterinarian if the smell or discharge persists for more than 48 hours, if there is obvious pain or if the dog loses its balance. Otitis does not cure "on its own".

Hip and elbow dysplasia: the problem of the joints

Dysplasia is a malformation of the joint that causes progressive wear. It is hereditary and multifactorial: genetics, rapid growth, excess weight and excessive exercise in developing puppies all play a role.

Most affected breeds

German Shepherd, Labrador, Golden Retriever, Rottweiler, Saint Bernard and French Bulldog, among other large and giant breeds.

Early signs

Stiffness when getting up after sleeping.
Difficulty climbing stairs or jumping into the car.
"Bunny hopping" when running (moving both hind legs together).
Less desire to play or tiredness after little exercise.
Frequent turning of the paw outward when standing.

Diagnosis and pain management

The diagnosis is made with X-rays (from 4-6 months in at-risk breeds). Management combines:

Strict weight control: every extra kilo multiplies the joint load.
Moderate and controlled exercise: swimming and gentle walks are ideal.
Supplementation with omega-3, chondroitin and glucosamine (check the dose with your vet).
Physiotherapy and anti-inflammatories in phases of pain.
Surgery in serious cases, especially in young dogs.

The sooner it is detected, the more options there are to slow the progression.

Periodontal disease: 80% of dogs suffer from it by age 3

The figure is striking: around 80% of dogs over 3 years of age have some degree of periodontal disease. And it is not just a dental problem: the bacteria in the mouth pass into the bloodstream and can affect the heart, kidneys and liver.

How to recognise it

Persistent bad breath (the earliest sign).
Yellow-brown tartar at the base of the teeth.
Red, inflamed gums that bleed when brushing.
Drooling, difficulty eating, loose or missing teeth.

How to brush the teeth correctly

Start with your finger or a gauze so the dog gets used to it (1-2 weeks).
Move on to a brush and toothpaste for dogs (never human toothpaste: fluoride and xylitol are toxic).
Brush at a 45° angle over the gum line, with circular movements.
Do it daily if you can; at least 3 times a week.
Support with dental snacks and chewing toys, but they do not replace brushing.

A professional scaling at the clinic every 1-2 years (depending on the dog) completes the routine.

Dermatitis and skin allergies: the great puzzle

Chronic itching, hair loss and skin lesions almost always respond to one of three causes: food allergy, environmental allergy or parasitic problems. Distinguishing them is key, because the treatment is completely different.

Type	When it appears	Typical areas	Diagnostic key
Food	All year round	Ears, paws, perianal area	Elimination diet 8-12 weeks
Environmental (atopy)	Seasonal or all year round	Armpits, groin, paws, face	Seasonal pattern, response to treatment
Parasitic (fleas/mites)	All year round, worse with heat	Back, base of the tail, neck	Visualisation of the parasite, skin scraping

Signs that require a veterinary consultation: itching that prevents sleeping, wounds from scratching, hair loss over extensive areas, bad smell or lesions that ooze.

Support measures at home:

Baths with medicated shampoo as directed by the veterinarian (not for human use).
Wash bedding frequently and vacuum well.
Strict and continuous antiparasitic control, all year round.
Do not change the diet on your own if you suspect a food allergy: the elimination diet must be supervised.

The ideal preventive calendar

A healthy dog stays healthy with an orderly routine. This is the calendar we recommend:

Stage	Veterinary check-up	Vaccines	Deworming	Dental health
Puppy (0-12 months)	Every 3-4 weeks until the schedule is completed	Full schedule + rabies	Internal and external monthly	Getting used to brushing
Adult (1-7 years)	Once a year	Annual boosters	Internal and external as per vet	Brushing and annual review
Senior (7+ years)	Every 6 months	As per vet	As per vet	Review 1-2 times/year

Also, ask the veterinarian to note the weight at every visit: the weight curve is one of the best early indicators of many problems.

Conclusion: your dog talks to you every day

Detecting in time does not require a master's degree in veterinary medicine. It requires consistency: looking, touching, weighing and asking. The five diseases in this guide — obesity, otitis, dysplasia, periodontal disease and dermatitis — are the most common precisely because they set in slowly. Your best tool is daily observation and an annual check-up that is never skipped.

And if you want to go deeper, at DogStar we have prepared practical guides on canine care, feeding and health so you don't lack information. As a reader of this blog, use the code DOGSTAR10 and get a discount in our store. 🐾

👉 Visit dogstar.club and discover all the guides.

This article is informative and does not replace the diagnosis or treatment of a veterinarian. In the presence of any symptom, always consult a professional.