Does My Dog Have Skin Allergies? Signs & Treatment

Is your dog scratching through the night, chewing at their paws, or back at the vet for another ear infection? Itching that keeps returning after it's been treated is rarely just dry skin. It usually means an allergy is driving it.

There are only four kinds of skin allergy in dogs, and they're told apart by pattern rather than by a test. The catch is that the pattern takes weeks to read properly.

So pet parents treat the symptom instead. A different shampoo. A food swap. A steroid course from a locum who hasn't seen the dog before. The itch settles, comes back, and nobody names the cause.

Getting an answer means working through it in order with your vet, and that visit goes better when you know what's coming.

A skin allergy in dogs is an immune overreaction to something ordinary that shows up as inflamed, itchy skin. The trigger might be a flea bite, a food protein, pollen, or something they've touched.

Vets call it allergic dermatitis. The itch isn't the trigger irritating the skin. It's your dog's own immune system responding to something it has decided is a threat.

That response damages the skin barrier, and skin that can't hold its defences lets yeast and bacteria move in. Those secondary infections itch more than the allergy did, which is why clearing them is always the first job.

Allergies are largely inherited. The tendency to react is genetic, and some breeds carry more of it than others. Allergies also build through repeated exposure, so a long uneventful history with something rules nothing out. A dog can tolerate chicken, or a particular lawn, for years and then start reacting.

Most dogs show their first signs between one and three years old. If itching starts in a dog over seven, tell your vet, because the likely causes are different.

Itching that keeps coming back after treatment is the sign worth acting on, more than how hard your dog scratches on any given day.

• Scratching, rubbing along the furniture, or worrying at one spot again and again
• Brown or rust-coloured staining on the paws, from saliva where they've been licking
• Recurrent ear infections, because an inflamed canal lets yeast and bacteria overgrow
• Skin that has thickened and darkened, from months of irritation rather than the allergy itself
• Patchy hair loss where scratching has broken the coat
• Hot, red skin at the belly, groin and armpits, where the coat is thinnest
• A musty smell, which usually means yeast has taken hold

Most itching can wait for a normal appointment. These can't:

• Swelling of the face or muzzle, hives, or any difficulty breathing
• Skin that is broken, bleeding or weeping
• A dog who cannot settle or sleep

This is a reaction to flea saliva, not to an infestation. One bite is enough, which is why "he doesn't have fleas" doesn't rule it out.

It concentrates at the tail base, the rump and the back legs. That distribution is distinctive enough to be a strong clue on its own.

Your vet will want this covered properly before anything else, because it's the cheapest thing to eliminate. Keep every pet in the house on flea prevention year round, not just the itchy one.

Food allergy itches all year and tends to settle on the face, ears, paws and belly. Recurrent ear infections are a common early sign, and often the first thing anyone notices.

The trigger is a protein, and it develops after long exposure rather than after a food change. Some dogs also show digestive signs alongside the itch.

Confirming it takes a structured elimination diet run with your vet, which is the only reliable method. No blood, saliva or hair test can diagnose it.

Atopic dermatitis is a reaction to things in the environment: grass and tree pollens, dust mites, and mould. It settles on the face, paws, ears and belly, much like food allergy does.

It's diagnosed by exclusion, which is why food usually gets ruled out first. Our guide to atopic dermatitis in dogs covers triggers, at-risk breeds and long-term management.

Contact allergy is the least common of the four. It's a reaction to something your dog physically touched: garden chemicals, fertiliser, a cleaning product, sometimes a shampoo.

It shows up where the contact happened, so it's usually the belly, the chin or between the paw pads. Areas under thick coat are often spared. If a flare followed a new product or a freshly treated lawn, say so.

Skin allergies are rarely dangerous, but they don't resolve on their own, and the infections they cause get worse without treatment.

Book an appointment if you see:

• Skin that's raw, bleeding or infected
• A third ear infection within a year
• Itching that hasn't improved after a genuine diet trial
• Scratching that's disturbing your dog's sleep, or yours
• Thickened or darkened skin, which means this has been going on a while

Waiting usually costs more than the consult. Chronic skin change is slow to reverse, and a dog that has been itching for months often needs a longer course of treatment than one seen early.

One thing worth setting expectations on: this normally takes more than one visit. That's how the process works rather than a sign it's going badly.

Your vet works by elimination, clearing the straightforward causes before naming the harder one, which is why a first appointment often ends without a diagnosis.

Knowing the shape of it makes the process much less frustrating, and a little preparation genuinely speeds it up.

• When the itching started, and whether it has ever fully stopped
• Where on the body it began, before your dog spread it around
• Everything your dog eats, including treats, dental chews and flavoured medications
• Which flea prevention you use, the actual product name, and when you last gave it

• Photos of the skin at its worst. Skin has a habit of looking better on the day of the appointment
• The food packaging, or a photo of the ingredient panel
• Rough dates of previous ear or skin infections, and what was prescribed each time
• A note of anything new: a product, bed, lawn treatment, house move

There is no single test for atopic dermatitis. It is diagnosed by ruling out everything else, one cause at a time. Infections come first, because infected skin masks what is under it. Expect two or three visits over a few weeks. That feels slow, and it is still the fastest way there.

Infected skin itches on its own, so nothing else can be judged until it's cleared. Depending on what's found, this might mean a medicated wash, ear drops, an antifungal or antibiotics. If your dog also has an ear infection, our guide to dog ear yeast infections explains how those are treated and why they recur.

A diet trial can settle the skin, and it tells you whether food was the cause at all. That second part only works if the diet is strict: one vet-prescribed food and nothing else for 8 to 12 weeks.

Which food matters less than how strictly you run it, and our guide to food allergies in dogs covers the protocol.

A skin-support diet is a different thing. It suits a dog whose itch is not food-driven, or one you are feeding long-term once the trigger is known, but it will not give you a diagnosis. 

For a ranked comparison of specific products, see our best dog food for skin allergies guide.

Washing removes allergens sitting on the coat and reduces surface yeast and bacteria. With medicated washes, contact time matters more than frequency, so leave the lather on as long as the label says.

This is worth a word of caution, because more washing is the natural response and it can work against you. Washing too often strips the oils that hold the skin barrier together, and a shampoo that suits one dog can inflame another. One of our customers put it plainly:

Ask your vet which wash and how often, rather than working through the shelf. Our best dog shampoos guide covers what suits which skin.

Dog skin supplements like omega-3 fatty acids support the skin barrier and have anti-inflammatory properties. A 2025 review of the evidence found the case for supplementation to be modest, so treat it as skin support rather than a complete treatment.

Talk to your vet before starting anything, since quality and dosing vary widely.

In some cases, your vet may prescribe allergy medication as part of a skin support plan. What's prescribed depends on your dog's individual needs and history and is decided by your veterinarian.

Common approaches may include:

• Daily medications that interrupt the itch signal
• Injectable treatments given at the clinic and repeated every few weeks
• Immune-modulating medications for longer-term control
• Short courses of anti-inflammatory medication for acute flare-ups

Medication doesn't remove the underlying allergy, but it can be an effective support tool, particularly alongside treating infections and identifying the trigger. Whether any medication is suitable depends on the individual dog and should be determined by a veterinarian.

For pet parents whose dog has already been prescribed Apoquel, detailed safety and technical information is in our Oclacitinib Medication Information Guide.

• Keep every pet in the house on flea prevention all year, not just through summer.
• Wipe the paws and belly after walks in pollen season, which removes much of what they've picked up.
• Wash bedding weekly in hot water, the highest-value thing you can do for a dust mite allergy.
• Keep a short diary: dates, what changed, what you gave. This helps point your vet in the right direction during your next appointment.

Avoid human antihistamines and cortisone creams without advice, because they may mask signs your vet needs to see. Also avoid changing their food mid-trial, which restarts the clock.

Skin allergies can't be prevented because the tendency is inherited. Reducing exposure and catching flares early can help keep your dog comfortable long-term.

Once your vet has a plan, the script can be filled without another trip to the clinic.

Skin allergies are usually managed for life, so repeat prescriptions may become routine. You can send your vet's script to a registered Australian pet pharmacy like VLP Pharmacy and have it dispensed and delivered.

Our guide to ordering prescription skin allergy medication explains how, including what your vet needs to provide.