What Is My Dog Allergic To? How To Identify Dog Allergies

What Are the Main Types of Dog Allergies? 

Many dogs experience allergies, which typically fall into three categories: environmental, food-related, and contact-based. Environmental allergies, like sensitivities to pollen, are the most common in dogs, whereas food allergies are less common, and contact allergies (from grass or cleaning products, for example) tend to be rare but can still cause visible discomfort. If you’ve noticed your pup reacting at certain times of year, after meals, or following contact with specific surfaces, you’re not alone, and your vet can help identify the root cause with the right testing or management plan.

Three Main Allergy Types 

Allergy Type	Common Triggers	Typical Signs	Seasonality
Environmental / Seasonal	Pollen, dust mites, mold spores	Scratching, skin or coat changes, head shaking	Seasonal or    year-round
Food Allergies	Chicken, beef, dairy, wheat, soy	Occasional digestive upset, scratching, head shaking	Year-round – relatively uncommon compared to environmental allergies, although food intolerances may occur more frequently
Contact Allergies	Fabrics, cleaning products, grass, shampoos	Localized changes to skin and coat and scratching at contact points	Varies by exposure

Environmental Allergens (The Most Common Type of Dog Allergy): 

• Tree pollen (spring: March–May) 
• Grass pollen (summer: May–July) 
• Weed pollen (fall: August–October) 
• Dust mites (year-round, worse in winter) 
• Mold spores (year-round, worse in damp conditions) 
• Flea saliva (seasonal in some regions) 

Common Dog Food Allergens: 

• Chicken (most common protein allergen in dogs) 
• Beef 
• Dairy products (milk, cheese) 
• Wheat and grains 
• Soy 
• Eggs 
• Fish 

Common Contact Allergens in Dogs: 

• Synthetic fabrics (bedding, carpet) 
• Cleaning products (floor cleaners, detergents) 
• Grass and plants 
• Topical products (shampoos, flea treatments) 
• Rubber or plastic (bowls, toys) 

Environmental allergies are the most common type seen in dogs, simply because it’s hard to avoid everyday triggers like pollen, dust mites, or mold spores, which can be tough on sensitive pups. Discomfort can increase during high-allergen times like March–May, May–July, or August–October.

Since these allergens are present both indoors and outside, many dogs experience signs year-round, not just seasonally. Spotting a pattern can be tough when triggers are everywhere, every day. 

Food allergies are often one of the first things pet parents worry about, but true food sensitivities are actually pretty rare. Ingredients like chicken, beef, dairy, or wheat may be involved, but in many cases, a pup’s discomfort is actually caused by something in their environment. For instance, flea allergy dermatitis is one of the most common causes of itching in dogs, and a single flea bite can cause prolonged itching. That’s why it’s important to work closely with your vet before making major food changes – they’ll help rule out more common causes first and guide you toward the right next step. 

Key takeaway: Dogs can react to a few different allergen types, most often from their environment, sometimes from their food, and occasionally through direct contact. Understanding the most likely triggers based on your dog’s signs and lifestyle can help you and your vet build the right care plan, one step at a time. 

What Are the Signs My Dog Has Allergies? 

If your dog has been scratching more frequently, especially around the paws, ears, face, or belly, it could be a sign of allergies. You might also notice frequent ear issues (commonly 3 or more per year), skin and coat changes, thinning fur from scratching, or occasional digestive changes. Try keeping a simple log of when signs appear and share it with your vet, it can make a big difference in figuring out what’s going on. 

Common Allergy Signs (Environmental and Contact): 

• Persistent scratching lasting more than 2–3 weeks, especially around the paws, ears, face, or belly 
• Skin and coat discomfort or changes 
• Recurring ear issues (such as frequent head shaking or ear scratching, commonly 3+ times per year) 
• Hair thinning or fur loss from frequent scratching or licking, particularly on the paws or sides 
• Areas of affected skin from repeated licking or scratching 
• Changes to the eye area such as increased tearing 
• Occasional sneezing or reverse sneezing 
• Excessive paw licking or chewing (including brown staining on light‑colored paws) 
• Face rubbing against carpets, furniture, or bedding 

Food Allergy-Specific Signs: 

• Occasional digestive upset (diarrhea, vomiting, gas) 
• Scratching (similar to environmental allergies) 
• Recurrent ear infections 
• Skin changes (color, texture) 
• Signs occur year-round (not seasonal) 
• Signs may appear within hours to days after eating trigger food 

Allergy Severity Levels: 

Severity	Signs	Frequency	Action Needed
Mild	Occasional scratching, slight skin color / texture changes	Seasonal, 2–4 weeks per year	Monitor
Moderate	Frequent scratching, ear infections 1–2x / year, visible skin color or texture changes	Seasonal or occasional year-round	Vet consultation recommended
Severe	Constant scratching, commonly 3+ ear infections / year, hair loss, significant skin changes	Year-round or severe seasonal	Vet consultation required

Paws and ears are two of the most common areas where signs of sensitivities show up in dogs. These areas are more exposed to environmental triggers like grass, dust, or pollen, and they naturally retain more moisture, especially after walks or baths. This combination can make them more reactive in dogs prone to allergies. 

Keeping a daily log for 2–4 weeks can be incredibly helpful for identifying patterns and discussing them with your veterinarian. Note the frequency of scratching sessions, which areas are affected, what time of day signs appear, and potential triggers like food, outdoor time, or changes in environment. A simple notepad or phone app can make tracking easier over time. 

If your dog has been itching for more than 2–3 weeks, especially around the paws or ears, it may be a sign of an underlying sensitivity - seek advice from your veterinarian on the best methods of support. Keeping a simple log for 2–4 weeks can help reveal helpful patterns and give your vet the insights they need to support your pup’s comfort and care. 

Could My Dog Be Allergic to Their Food? 

Food sensitivities in dogs often show up as year-round signs like scratching after meals, soft stools, or paw licking. Unlike seasonal allergies, food-related issues require an 8–12 week elimination diet using a novel or hydrolyzed protein, guided by your vet. Common triggers include chicken, beef, dairy, and wheat, but every dog is different. While the process can feel overwhelming, your veterinarian can help create a tailored plan to identify the cause and support your pup’s comfort and wellbeing. 

Signs That Suggest Your Dog May Have A Food Allergy vs An Environmental Allergy: 

• Signs are visible year-round (not just spring or fall) 
• Digestive discomfort along with skin changes 
• Signs started after diet change 
• No improvement with seasonal changes 
• Ear infections persist even in winter 
• Signs in young dogs (under 1 year) may suggest food allergy 

Elimination Diet Process – Figuring Out Which Foods Your Dog Is Reacting To 

Your vet may recommend an elimination diet to identify food sensitivities. It’s important to follow the guidelines your vet gives you, and to keep a careful record of observations. 

Phase	Duration	What Happens	Goal
Elimination	8–12 weeks	Feed only novel protein or hydrolyzed diet	Clear all signs
Reintroduction	2 weeks per ingredient	Add one old ingredient at a time	Identify specific allergen
Maintenance	Ongoing	Avoid identified allergens	Support normal response to allergens

Elimination Diet Process – What To Do To Ensure Clear Findings 

• Feed only as directed as directed by your veterinarian for 8–12 weeks (no treats, table scraps, extras) 
• Choose a food that contains a novel protein (a protein your dog has never eaten: for instance venison, duck, rabbit, kangaroo) 
• Or use a hydrolyzed protein diet, where the proteins are broken into very small pieces so the body is less likely to react to them 
• Track any signs weekly. Many dogs may need the full 8–12 weeks before signs improve 
• Under veterinarian guidance, reintroduce old ingredients one at a time for 2 weeks each 
• If signs of reaction return within 2 weeks of reintroduction, notify your veterinarian immediately 

An elimination diet usually takes 8–12 weeks because it gives your dog’s system time to clear out previous ingredients and adjust to a simplified, carefully selected diet. This process may feel slow, but it’s an important step toward helping your dog feel more comfortable and finding what truly works for them. 

Even with the best intentions, this kind of diet can be tricky to manage. Treats, table scraps, or shared food from other pets can accidentally reintroduce potential triggers. It’s also understandable to feel discouraged if signs don’t improve right away, but many dogs need the full 8–12 weeks before signs improve. 

Having your vet guide the process can make a big difference. They’ll help you choose a suitable hydrolyzed or novel protein option, keep the diet nutritionally balanced, and support you through each phase. They can also help pinpoint common food allergens, like chicken, beef, dairy, or wheat, during reintroduction. 

An elimination diet is the most trusted way to uncover food sensitivities, but success takes time, consistency, and the right support. Partnering with your vet helps ensure your pup gets the care they need, every step of the way. 

How Do I Know If My Dog Is Allergic to Environmental Allergens? 

Environmental allergies are often seasonal, worsening in spring, summer, or fall, but some dogs may show signs year-round. Your veterinarian may recommend intradermal skin testing or blood allergy testing to help identify specific triggers like pollen, dust mites, or mold spores. These results may guide treatment plans, including environmental adjustments, or vet-prescribed therapies. Next step: Talk to your vet about medications or allergy testing if you’ve noticed recurring seasonal or severe allergic signs in your dog. 

Signs Suggesting Environmental Allergy: 

• Signs intensify during specific seasons 
• Year-round signs increase seasonally
• Signs lessen when indoors or after rain (pollen washed away) 
• Signs increase after outdoor activities 
• No digestive upset (primarily skin and ear changes) 
• Signs started in adulthood (environmental allergies often develop at 1–3 years old) 

Environmental Allergy Testing Options: 

Test Type	How It Works	Accuracy	Cost	Timeline
Intradermal skin test	Small amounts of allergens injected under skin	Most accurate (gold standard)	$550 – $1000	Results in 20–30 minutes
Blood allergy test	Blood sample tested for allergen-specific antibodies	Less accurate than skin test	$400 – $800	Results in 1–2 weeks

Allergy testing in dogs is most often used to identify environmental triggers like pollen, dust mites, or mold, not food allergies. Veterinarians may recommend skin or blood testing when a dog has ongoing or seasonal itching that does not improve with basic care. These tests help guide long-term management plans, such as environmental adjustments or immunotherapy, rather than providing a simple yes-or-no diagnosis. Your veterinarian can help determine whether allergy testing is useful for your dog based on their signs and history. 

Is My Dog Allergic to Chicken or Other Proteins? 

Chicken is one of the most commonly reported food allergens in dogs, along with beef, dairy, and wheat. These reactions often develop slowly over time, not suddenly. If you’ve noticed ongoing signs that could point to a food sensitivity, a vet-guided 8–12 week elimination diet, followed by careful reintroductions, is the most reliable way to get answers. 

Helpful next step: over-the-counter “limited ingredient” diets are not reliable for diagnosing food allergies due to cross-contamination – prescription diets are preferred for elimination trials. Talk to your veterinarian about creating an elimination plan tailored to your dog’s needs. With the right support, uncovering a protein-related sensitivity can feel more manageable.

Common Food Allergens in Dogs (Ranked) 

Rank	Allergen	Prevalence	Why It’s Common
1	Chicken	Most common	Most frequently used protein in dog food
2	Beef	Very common	Second most common protein in dog food
3	Dairy	Common	Often in treats and some foods
4	Wheat	Common	Common grain in dog food
5	Soy	Less common	Used as protein source in some foods
6	Eggs	Less common	Used in some foods and treats

How Protein Allergies Develop in Dogs: 

• Dogs can be exposed to a protein for months to years before an allergy develops 
• Dogs can’t be allergic to a protein they have never eaten 
• Dog allergies develop through repeated exposure (their immune system becomes sensitized) 
• Dogs don’t suddenly become allergic overnight 
• Dogs can develop allergies to previously tolerated proteins after long-term exposure 

Signs Your Dog May Be Allergic to Current Protein: 

• Year-round scratching and skin changes (texture, color) 
• Occasional digestive upset (diarrhea, vomiting, gas), along with skin changes 
• Signs started showing after your dog has been on the same food for 6+ months 
• No seasonal pattern to signs 
• Ear infections persist year-round 

When it comes to food sensitivities, simply switching to a different protein won’t confirm if an allergy is present. A true diagnosis requires a structured 8–12 week elimination diet, where your dog is fed only one carefully chosen protein and carbohydrate source. This process gives your dog’s system time to reset and helps reveal whether food is contributing to the signs you’ve noticed. 

Your veterinarian may recommend a novel protein, something your dog hasn’t eaten before, like venison, rabbit, duck, kangaroo, or certain fish. These proteins are less likely to trigger a response. Some diets also use hydrolyzed proteins, which are broken down so small that the immune system may not recognize them. Either option can be a helpful starting point. 

It’s easy to assume that switching from chicken to beef might help, but if your dog is sensitive to both, the signs may continue. That’s why it’s important to follow a vet-guided protocol and avoid any extra treats or foods during the trial. A properly managed elimination diet offers the clearest path to understanding your dog’s unique needs. 

Why Does My Dog Suddenly Have Allergies? 

Allergies often appear between 1–3 years of age, but signs can emerge at any stage as your dog’s immune system changes or encounters new triggers. What seems sudden may actually result from a gradual sensitization process, where repeated exposure to allergens like pollen or proteins builds up over time. If signs have recently worsened, consider whether anything in your dog’s routine, diet, or environment has changed. Noticing when and how these signs appear is a helpful first step, keeping a simple log can provide valuable insight for your veterinarian. 

Why Allergy Signs Can Seem Sudden: 

• Allergies often build up slowly – the immune system usually needs repeated exposure over time before reacting noticeably. 
• Early signs are easy to miss – mild scratching or tummy troubles may not stand out right away. 
• Sometimes it’s a tipping point – your dog may have reached a level of exposure that their body now struggles to manage. 
• Changes in environment can play a role – moving to a new area may introduce different pollens or allergens. 
• Seasonal shifts can make a difference – some dogs show signs during their first spring or fall in a new place. 
• Age matters – many dogs begin to show signs of environmental sensitivities between 1–3 years old. 

Common Situations That May Trigger Allergy Signs: 

• Experiencing their first spring or summer in a new location with unfamiliar pollens or plants 
• Transitioning from an apartment to a home with a yard, increasing outdoor exposure 
• Encountering a particularly high pollen season, which can overwhelm your pup’s system 
• Going through a stressful change, like boarding, moving, or welcoming a new family member or pet 
• Recovering from a recent illness or medication, which may have impacted immune balance 
• Adjusting to a new diet, especially if there’s an underlying food sensitivity 
• Being exposed to something new in the home, like carpet, cleaning sprays, or plants 

How Allergies Develop Over Time 

If your pup seems to be reacting to something out of the blue, you’re not alone, many pet parents are surprised when allergy signs seem to appear suddenly. But in most cases, allergies build up quietly over time. Your dog’s immune system goes through a sensitization process, which means it needs months to years of repeated exposure to a trigger (like pollen or food proteins) before reacting. 

That’s why most environmental allergies begin between 1–3 years old, this is when a dog’s immune system has matured enough to recognize certain substances as irritants after ongoing exposure. So, what looks like a “sudden” reaction is often your dog reaching a tipping point after months of gradual buildup. 

If you’ve started noticing changes in your dog’s comfort or behavior, keeping a log of when signs appear, whether seasonally, after meals, or during stressful times, can make a big difference. These patterns help your veterinarian uncover possible triggers and recommend next steps to support your dog’s wellbeing. 

Key takeaway: Allergies usually develop gradually, not instantly. Noticing when signs appear can help uncover what’s really going on and give your pup the relief they deserve. 

What Should I Do If I Think My Dog Has Allergies? 

If your dog has shown allergy-like signs for more than 2–3 weeks, start by keeping a 2–4 week log – note when the signs appear, what they are, and any patterns. This record can help your veterinarian guide next steps, like an elimination diet or allergy testing. While you wait for a diagnosis, gentle steps like wiping paws after outdoor play, using air purifiers, or avoiding suspected triggers may help. Always speak with your vet to ensure the right care plan for your dog’s needs. 

Helpful steps to take before your vet visit: 

• Gently keep a 2–4 week wellness log, noting where signs show up, how intense they seem (for example, on a 1–10 scale), when they appear, and anything that might trigger them 
• Take clear photos of any affected areas so you and your veterinarian can compare changes over time 
• Notice whether signs seem seasonal (worse in spring, summer, or fall) or present throughout the year 
• Write down everything your dog eats, including treats or chews, if food sensitivities are a concern 
• Make note of how often ear-related issues occur over time 
• Schedule a veterinary appointment to help guide proper diagnosis and next steps 

Environmental Tips While Waiting for Answers from Your Vet 

• Rinse your dog’s coat with water or bathe gently after outdoor time to help remove pollen 
• Wipe paws with a soft, damp cloth after walks to reduce allergen build-up 
• Use a HEPA air purifier indoors to help lower airborne irritants like pollen or dust 
• Wash your dog’s bedding regularly in warm water (weekly is a good goal) 
• Vacuum common areas 2–3 times a week to help reduce indoor allergen buildup 
• Keep windows closed on high pollen days when possible 
• Avoid doing yard work while your pup is outside, as it can stir up grass, mold, or pollen particles 

When to Call the Vet Right Away 

• Swelling around the face, muzzle, or legs 
• Changes in breathing or unusual breathing sounds 
• Sudden drop in energy or unusual tiredness 
• Widespread skin changes (like hives or intense scratching) 
• Digestive upset (vomiting or loose stools) that seems unusual 
• Reactions that start shortly after eating something new or spending time in a new environment 

During your vet visit, your veterinarian will likely begin with a full physical exam and a detailed discussion of your dog’s signs, so bringing a daily log covering 2–4 weeks can be incredibly helpful. This log may include when signs started, how often they appear, severity on a 1–10 scale, and anything new in your dog’s diet, environment, or routine. Based on this, your vet might recommend allergy testing (such as blood or skin testing for environmental triggers) or an elimination diet if a food allergy is suspected. 

Once a diagnosis is made, your vet may suggest a tailored plan that could include a combination of treatments. Options might involve immunotherapy (injections or oral drops that help build tolerance), prescribed medications to help manage signs, environmental adjustments like rinsing after outdoor play or using air filters. Your dog’s plan will depend on the type and severity of their sensitivities, and what works best for your lifestyle. 

The right care starts with an accurate diagnosis. Keeping a clear log of your dog’s signs and visiting your vet early can make all the difference in finding a plan that helps your pup feel more comfortable, no matter the season. 

Frequently Asked Questions About Identifying Dog Allergies 

1. Can I test for dog allergies at home? 

There isn’t a reliable at‑home test that can accurately diagnose dog allergies, as proper identification usually requires veterinary testing like blood tests, skin testing, or a structured elimination diet. What can help is tracking signs at home for 2–4 weeks and sharing patterns with a veterinarian, who can guide appropriate testing. 

2. Is my dog allergic to cats? 

Dogs can react to cat dander, saliva, or urine proteins, and signs may appear when dogs spend time near cats. These reactions are typically identified through veterinary allergy testing, not observation alone. If signs appear consistently around cats, a veterinarian can help confirm triggers and suggest management steps like air filtration or separation. 

3.Is my dog allergic to peanut butter? 

Peanut allergies are uncommon in dogs, but reactions can happen, especially within a few hours of eating peanut butter. In many cases, issues are linked to added ingredients rather than peanuts themselves. Always avoid any peanut butter containing xylitol, which is unsafe for dogs. 

4. Why is my dog allergic to everything? 

Dogs are rarely allergic to “everything,” even if signs feel widespread. More often, dogs react to several related environmental triggers or one underlying issue that hasn’t been fully identified. Veterinary testing typically identifies a defined group of allergens, often 5–15, not unlimited, and can help clarify next steps for complex cases. 

5. What causes allergic reactions in dogs? 

Allergic reactions occur when a dog’s immune system becomes sensitized to substances like pollen, food proteins, or environmental particles over months to years. Repeated exposure can lead to immune overreaction, which may show up as scratching or skin discomfort. A veterinarian can help determine triggers and recommend supportive care options. 

6. Is my dog having an allergic reaction right now? 

Most allergy‑related signs develop gradually over days or weeks, not suddenly. Mild reactions may settle with monitoring, but sudden changes, especially facial swelling, breathing difficulty, or weakness within minutes to hours, require immediate veterinary care. When in doubt, contacting a veterinarian promptly is always the safest next step. 

Final Thoughts: Identifying What Your Dog Is Allergic To 

• Dogs can develop sensitivities to three main types of allergens:
  Environmental triggers like pollen, dust particles, or mold
  Food ingredients such as chicken, beef, dairy, or wheat
  Contact allergens from things like grass, fabrics, or cleaning products 
• You might notice common signs like frequent scratching (especially around the paws, ears, and belly), soft stools after meals, repeated ear issues (more than three times a year), or patches of hair loss from licking or scratching. 
• To find out what’s going on, your veterinarian may recommend testing. For food-related concerns, this often means an elimination diet that lasts 8 to 12 weeks. For environmental allergies, your vet might suggest a blood or skin test, with results typically coming back in 1 to 2 weeks. 
• Keeping a daily log for 2 to 4 weeks is a great first step. Noting when and where signs appear, how often they happen, and anything that might be triggering them can really help your vet piece things together. 
• While you’re waiting on answers, a few gentle habits may help. Try rinsing your pup’s paws after walks, using an air purifier indoors, and washing their bedding each week to help reduce allergens in their environment. 
• Managing allergies is often an ongoing journey that may include environmental changes, vet-recommended treatments, and supportive care. 

Please note: This article is for informational and educational purposes only and is not a substitute for professional veterinary care. Always consult your veterinarian before making changes to your dog’s diet, or if your dog has ongoing symptoms, diagnosed allergies, or is taking medication.

Sources: What Is My Dog Allergic To? 

• Allergies in Dogs – MSD Veterinary Manual  
• Allergies in Dogs – VCA Animal Hospitals 
• Decoding Dog Allergies: Signs, Testing, and Treatment – AAHA 
• 10+ Common Allergies in Dogs & Treatment – Sploot Vets