4 key points on dog allergies:
1
Signs
+
Unlike
humans,
dogs
most
often
show
allergies
through
skin-related
signs
such
as
itching,
redness,
hair
loss,
skin
irritation,
and
ear
infections
(otitis).
2
Causes
+
Allergies
occur
when
the
immune
system
mounts
an
exaggerated
response
to
substances
that
are
harmless
for
most
dogs
but
trigger
a
reaction
in
that
individual.
3
What to do
+
Diagnosing
allergies
is
relatively
straightforward,
but
identifying
the
exact
allergen
takes
time.
Work
with
your
vet
to
first
rule
out
parasites,
then
investigate
possible
triggers
such
as
food,
environmental
factors,
or
contact
reactions.
4
Treatment and prevention
+
Most
allergic
dogs
need
a
combination
of
treatments,
tailored
to
their
condition.
With
the
right
approach,
allergies
can
be
controlled
and
your
dog
can
remain
comfortable
for
life.
Allergies in dogs are common and can significantly impact quality of life. Each dog’s allergy profile is unique, but many respond well to practical management strategies.
How can you tell if your dog is allergic?
Common locations of skin lesions in dogs with skin allergies
In humans, allergies often cause runny noses and watery eyes. In dogs, however, skin problems are by far the most frequent sign.
Typical locations include the belly, groin, armpits, paws, and between the toes—but this can vary widely between dogs and breeds.
Common symptoms include:
Itching
The three most frequent causes of itchy skin are parasites (fleas, mites), infections, and allergies. Chronic itching causes distress and ongoing irritation.
Scratching and licking
Dogs naturally scratch or lick to relieve itching. When itching persists without parasites, repeated scratching or licking can damage the skin, a process known as self-trauma. This ongoing irritation may lead to secondary bacterial skin infections, such as bacterial pyoderma or yeast infections (Malassezia). Over time, saliva can stain on light-colored coats.
Go to the next page for illustration of the disorder(s)
Dr Chiara Noli, Hair loss and inflammation on the thorax in an allergic dog
Dr Chiara Noli, Inflammation and hair loss between the pads. This is a common feature in dog allergies
Redness and inflammation
Scratching fuels inflammation, which in turn causes more itching—the classic “Itch-Scratch Cycle.”
Hair loss
Constant trauma damages follicles, pulling out hairs and creating bald patches.
Flaky skin
Dry, flaky “dandruff” may appear either in localized patches or across the body.
Skin changes
Chronic inflammation causes thickening and darkening of the skin (“lichenification”), as well as bumps (papules).
Go to the next picture for illustration of the disorder(s)
Dr Susanne Ahman, Inflammed ear pinna. This is common in allergic dogs
Ear diseases
Yes, you read that right! Remember, the ear is lined with skin, and actually ears are a really good marker of skin health: in the ear, mild allergic inflammation can rapidly progresses to secondary bacterial or yeast infections. These can easily be treated, but the underlying condition is still there. As a result, we often consider that a young dog who has repeated ear infections for no obvious reason is at high risk of developing full blown allergic skin disease later in life.
What causes dog allergies?
An allergy can be considered a “mistake” by the dog’s immune system. Although extremely powerful, the immune system isn’t infallible and can sometimes start attacking things it shouldn’t. When it attacks healthy body cells by mistake, we call this an autoimmune disease. An allergen is a substance that triggers an allergic reaction in some dogs because their immune system mistakenly identifies it as a danger.
Allergens: the triggers for dog allergies...
An allergen is a substance that the immune system mistakenly identifies as a threat. There’s a wide range of different allergens that dogs can react to.
Common allergens include:
Flea saliva: A reaction to flea saliva is called Flea Allergic Dermatitis (FAD), and many dogs are highly sensitive to it.
Flea saliva: A reaction to flea saliva is called Flea Allergic Dermatitis (FAD), and many dogs are highly sensitive to it.
Environmental allergens: Pollens, molds, and surface proteins from mites (storage and dust mites are frequent allergens for many dogs).
Environmental allergens: Pollens, molds, and surface proteins from mites (storage and dust mites are frequent allergens for many dogs).
Food allergens: Although food allergies are less common, when they occur, they’re usually caused by proteins (most often from meat). A common misconception is that food allergies cause digestive issues — in fact, this is rare. Most food allergies result in itchy, sore skin just like other allergies do.
Food allergens: Although food allergies are less common, when they occur, they’re usually caused by proteins (most often from meat). A common misconception is that food allergies cause digestive issues — in fact, this is rare. Most food allergies result in itchy, sore skin just like other allergies do.
...penetrating the dog’s barriers and causing inflammation...
In allergic dogs, the microbial skin barrier is altered — the natural “good” bacteria are less diverse and less protective. The mechanical skin barrier is also less effective, allowing allergens to penetrate more easily. Scratching and licking worsen this by damaging the skin and exposing immune cells to more allergens, fueling inflammation.
The immune system of predisposed dogs tends to overreact and fails to calm down easily. Unlike in humans, histamine from mast cells plays a smaller role in dogs, which explains why antihistamines are usually less effective for them.
These immune reactions trigger changes in local tissues — increased blood flow, white blood cell activity, and nerve stimulation — leading to redness, itching, and discomfort.
Breed predisposition
While any breed (or mixed-breed) can be affected, certain breeds are more prone to allergies, including West Highland White Terriers, Golden Retrievers, Labrador Retrievers, Shar Peis, Dalmatians, Boxers, and Boston Terriers.
Symptoms typically appear between 6 months and 3 years of age. If they begin later (after 6 years), another underlying issue is often involved.
What to do? How to diagnose dog allergies?
Determining whether a dog has allergies is relatively straightforward, though sometimes slow. Identifying what they’re allergic to is the real challenge.
Diagnosing allergic skin disease can be a long and sometimes frustrating process, but it’s the best way to reach a clear diagnosis so you and your vet can find the right treatment plan.
There is no single test for allergic skin disease: blood and skin tests can help identify allergens, but they rarely confirm whether a dog is allergic. Diagnosis involves ruling out other causes and thoroughly assessing symptoms and history.
First, rule out parasites and skin infection
This may seem unnecessary, but it’s essential to rule out the most common causes of itching first — fleas and other parasites. Your vet may recommend changing flea or parasite treatments. This isn’t a criticism; it’s a standard step to ensure accuracy.
Your vet may also perform coat brushings to check for fleas, and skin scrapes for mites such as Sarcoptic Mange or Demodectic Mange. If a skin infection is detected, it must be treated before investigating further.
Once parasites and infections are ruled out, we move to the next step.
Recent changes
Have there been any recent changes in laundry detergent, food, bedding, or other environmental factors? Allergic reactions can appear either shortly after exposure or develop over time as sensitivity builds. However, these changes are often not the underlying cause.
Food allergies
Diagnosing food allergies is complex since they rarely show up in blood or skin tests. A dietary elimination trial is usually needed.
The dog must be completely removed from their regular diet (including treats and snacks) and placed on either a hydrolyzed diet (proteins broken down so the immune system doesn’t recognize them) or a novel protein diet (something the dog has never eaten before, such as salmon and tapioca).
This diet must be followed strictly for 8–12 weeks. If there’s no improvement, food allergy is unlikely. If there is, normal foods can then be reintroduced gradually to identify the trigger.
Environmental allergies
For environmental allergens (pollens, molds, mites, etc.), blood or skin tests can be helpful — but only when performed and interpreted by a veterinarian. Some commercial “allergy tests” are unreliable.
Even then, dogs may test positive for one allergen but react to another in real-life conditions, so results must be assessed carefully by your vet or a veterinary dermatologist.
Once the triggers are identified, long-term management can begin.
How are dog allergies managed?
Treatment needs to be customized and may change over time
Never try to manage even moderate allergic skin disease on your own — always consult your veterinarian.
Treatment depends on the cause and often involves multiple approaches that evolve over time. Without proper management, symptoms can worsen quickly.
There are four basic approaches that we can take to manage dog allergies:
1. Avoid the allergens where possible (e.g. frequent cleaning to minimize dust mites, regular preventative flea control, avoiding certain foods or cleaning products)
2. Topical approach to bring soothing ingredients where needed
3. Drugs to reduce itching and skin inflammation
4. Improve the dog’s immune tolerance to allergens
What is the prognosis of allergies in dogs?
Allergies are lifelong and require ongoing management. Most dogs need a combination of treatments to control symptoms effectively. Each dog’s allergy profile is unique — there’s no universal solution.
Using products with active ingredients like Ophytrium®, contained in DOUXO® S3 CALM, helps soothe irritated skin, support the microbial flora for healthy skin and support skins' physical barrier for a supple hydrated skin.
Learn more about
Find the right product for your pet
TAKE THE QUIZ
Safe for you and your pet
Recommended by veterinarians
Approved by pets and families
Is your dog suffering from allergies? Ask your vet for the best solution for your dog’s skin issues and learn more about DOUXO® S3 CALM, which helps soothe itchy, irritated, or allergic skin.