Best Allergy Meds for Dogs: 5 Top Choices for Relief

Allergies can turn a pup’s life from playful to uncomfortable. If you’re scrolling through pet health resources, you’re likely looking for the best allergy meds for dogs that can soothe itching, reduce inflammation, and bring back that wagging tail. In this guide, we’ll cover the most effective options, how to choose the right one, and practical tips for safe administration.

We’ll dive into drug classes, dosage guidelines, side‑effects, and real‑world comparisons. By the end, you’ll know which medication fits your dog’s needs and how to use it confidently.

Let’s explore the top choices and answer the most common questions from pet owners.

Why the Right Allergy Med Matters

Dog allergies affect about 12% of pet owners in the U.S., according to the American Veterinary Medical Association. Untreated allergies can lead to chronic skin infections, loss of weight, and decreased quality of life. Choosing the right medication reduces these risks and restores comfort.

Key Decision Factors

When selecting an allergy med, consider these three pillars:

• Severity of symptoms: Mild itching vs. severe dermatitis.
• Underlying health conditions: Dogs with liver or kidney issues need gentler options.
• Owner preference: Oral tablets vs. injectable biologics.

Balancing these factors ensures the best outcome for both you and your dog.

Top 5 Allergy Meds for Dogs

Below is a quick snapshot of the most popular choices, complete with dosage ranges and typical side‑effects. These medications are frequently recommended by veterinarians nationwide.

• Benadryl (Diphenhydramine) – 1–2 mg/kg every 8–12 hrs. Common side effects: drowsiness, dry mouth.
• Zyrtec (Cetirizine) – 0.2 mg/kg once daily. Common side effects: somnolence, gastrointestinal upset.
• Prednisone – 0.5–2 mg/kg daily. Common side effects: weight gain, polyuria, immunosuppression.
• Fexofenadine – 0.5 mg/kg once daily. Common side effects: minimal, mild GI upset.
• Lokivetmab (Cytopoint) – 2 mg/kg subcutaneously every 4 weeks. Common side effects: injection site reaction, rare anaphylaxis.

These options span everything from OTC antihistamines to cutting‑edge biologics. Use the table below to compare safety, dosing, and effectiveness side‑by‑side.

Choosing the Right One for Your Dog

Here’s a quick decision tree to help you narrow down options:

1. Are symptoms mild and episodic? Try an oral antihistamine like Benadryl or Zyrtec.
2. Do you need a longer‑lasting effect? Consider Fexofenadine or Lokivetmab.
3. Is your dog prone to severe inflammation? Prednisone may be necessary under strict vet supervision.

Always start with the lowest effective dose and monitor closely for side‑effects.

Practical Tips for Safe Administration

Even the best medication can backfire if not given correctly. Follow these steps to maximize safety and efficacy.

• Verify the dose with your vet before first use. Mis‑calculation can lead to overdose or under‑dose.
• Administer with food unless otherwise directed. This reduces stomach upset for most drugs.
• Keep a symptom diary. Note changes in itching, energy, or appetite within 48 hrs of starting therapy.
• Watch for drug interactions. If your dog is on other medications, discuss potential interactions with the vet.

By following these simple steps, you help ensure your dog experiences the full benefit of the chosen allergy med.

1. Oral Antihistamines for Quick Relief

Oral antihistamines are often the first line of defense against seasonal allergies.

They block histamine receptors, alleviating itching and swelling within minutes.

Choosing the Right OTC Antihistamine

Veterinary guidance recommends two main options for dogs: Benadryl (diphenhydramine) and Zyrtec (cetirizine).

Both are safe when dosed correctly, but they differ in onset time, duration, and side‑effect profiles.

Benadryl (Diphenhydramine)

Benadryl is the most widely available antihistamine for pets.

It typically begins working within 30 minutes and lasts 6–8 hours.

Common dosages range from 1–2 mg per kilogram of body weight, given every 8–12 hours.

Side effects include mild drowsiness and dry mouth, making it ideal for daytime use before exercise.

Zyrtec (Cetirizine)

Zyrtec offers a longer duration of action, up to 24 hours.

Its dosage is usually 0.2 mg per kilogram, once daily.

Because it is less sedating, it works well for late‑night flare‑ups.

Occasional gastrointestinal upset has been reported, so administering with food can help.

Actionable Tips for Safe Use

• Always calculate the dose by weight. A 25‑kg dog should receive 25–50 mg of Benadryl, not a flat adult human dose.
• Start with the lowest effective dose. Monitor the dog’s response for 30 minutes before giving a second dose.
• Use a pill‑pocket or flavored chew. This makes administration easier and reduces anxiety.
• Keep a medication log. Note the time, dose, and any side effects to discuss with your vet.

Real‑World Example: Summer Allergy Season

Emma’s 4‑year‑old Golden Retriever, Max, developed intense itching after hiking in the woods.

After consulting her vet, she gave Max 1 mg/kg of Benadryl at 8 am.

Within 45 minutes, Max’s scratching decreased by 70 % and he relaxed enough to play fetch.

Emma repeated the dose at 4 pm, and Max stayed comfortable until bedtime.

Key Statistics for Context

• According to the American Veterinary Medical Association, 68 % of dogs with seasonal allergies respond well to first‑line antihistamines.
• Studies show a 55 % reduction in itching severity within the first hour of Benadryl administration.
• Long‑term monitoring reveals fewer behavioral changes compared to prescription steroid therapy.

When to Escalate Beyond OTC

If your dog shows persistent itching or develops secondary infections, consider a veterinary‑prescribed option.

Prescription antihistamines like fexofenadine offer a gentler side‑effect profile for chronic use.

In severe cases, veterinarians may prescribe corticosteroids or biologics for rapid control.

By following these guidelines, you can safely harness the power of oral antihistamines to keep your dog comfortable during allergic flare‑ups.

2. Prescription Medications: Corticosteroids vs. Antihistamines

When OTC Medicine Isn’t Enough

Over‑the‑counter antihistamines are great for mild flare‑ups, but some dogs need a stronger bite. When symptoms persist beyond a week or become severe, a vet often steps in with prescription options.

Choosing the right prescription can mean the difference between a quick recovery and a long‑term health issue.

Corticosteroids: The Rapid‑Acting Powerhouse

Prednisone and its cousin prednisolone are the go‑to steroids for dogs with intense itching, swelling, or systemic inflammation.

Clinical studies show that up to 70 % of dogs with atopic dermatitis see noticeable improvement within 24–48 hours of starting prednisone.

Typical dosing ranges from 0.5 mg/kg to 2 mg/kg once daily, tapering over 2–4 weeks to minimize rebound flare‑ups.

• Pros: Fast onset, high potency, available in tablet and injectable forms.
• Cons: Risks of weight gain, polyuria, immunosuppression, and adrenal suppression with long‑term use.
• Best For: Dogs with severe dermatitis, eosinophilic granuloma complex, or systemic allergic reactions.

Prescription Antihistamines: A Gentler Alternative

Fexofenadine is a non‑sedating antihistamine that vets sometimes prescribe for dogs who need extended control without the side‑effects of steroids.

Data from the Veterinary Pharmacology Journal indicates that 60–65 % of dogs on fexofenadine maintain stable pruritus scores for up to 12 weeks.

Typical dosing is 0.5 mg/kg once daily, often combined with omega‑3 fatty acids for synergistic skin benefits.

• Pros: Minimal sedation, lower risk of systemic side‑effects, safe for long‑term use.
• Cons: Slower onset (often 2–4 hours), may be less effective for severe flare‑ups.
• Best For: Dogs with chronic mild to moderate itching, or owners who prefer a medication-free lifestyle.

Decision Matrix: How to Pick the Right Prescription

1. Assess Severity: Use a scoring system (e.g., CADESI) to quantify itching and inflammation.
2. Consider Health History: Dogs with diabetes, liver disease, or a history of steroid relapse may benefit from antihistamines.
3. Evaluate Duration: For short‑term flare‑ups, a single course of prednisone may suffice; for ongoing control, fexofenadine or a biologic like Lokivetmab is preferable.
4. Discuss with Your Vet: Review potential drug interactions, especially if your dog is on other medications.

Real‑World Example: Max’s Allergy Management

Max, a 5‑year‑old Labrador, had seasonal itching that worsened each spring. His owner tried Benadryl with limited success. After a vet visit, Max was started on a low‑dose prednisone taper for the first week, followed by daily fexofenadine to maintain control.

Within two weeks, Max’s CADESI score dropped from 35 to 12, and his owner reported no significant weight gain or behavioral changes.

Key Takeaways for Pet Owners

• Use prednisone only under strict veterinary guidance and for the shortest effective period.
• Consider fexofenadine for long‑term management if your dog tolerates it well.
• Always monitor for side‑effects: drowsiness, increased thirst, or sudden weight changes.
• Keep a medication log to track dosage, timing, and symptom changes.

By weighing the pros and cons of corticosteroids versus prescription antihistamines, you can tailor an allergy treatment plan that balances efficacy with safety for your canine companion.

3. Top 5 Allergy Meds for Dogs: Side‑Effect Comparison

Medication	Common Uses	Typical Dosage	Key Side Effects
Benadryl (Diphenhydramine)	Acute itching, allergic rhinitis	1–2 mg/kg every 8–12 hrs	Drowsiness, dry mouth
Zyrtec (Cetirizine)	Seasonal allergies, dermatitis	0.2 mg/kg once daily	Somnolence, gastrointestinal upset
Prednisone	Severe inflammation, autoimmune conditions	0.5–2 mg/kg daily	Weight gain, polyuria, immunosuppression
Fexofenadine	Allergic rash, pruritus	0.5 mg/kg once daily	Minimal, mild GI upset
Lokivetmab (Cytopoint)	Atopic dermatitis, long‑term control	2 mg/kg subcutaneously every 4 weeks	Injection site reaction, rare anaphylaxis

The table above gives a quick glance at the most common dog allergy medications. It’s a handy reference for vet visits and home dosing plans. Below, we break down each drug, share real‑world tips, and present the latest data so you can choose the safest, most effective option for your pup.

Benadryl (Diphenhydramine)

Benadryl is often the go‑to over‑the‑counter option for sudden itching spikes. Veterinarians recommend 1–2 mg per kilogram of body weight every 8–12 hours. This dosage range keeps side effects low and works within the first 30 minutes to an hour.

Common side effects include drowsiness and dry mouth. If your dog seems unusually sleepy, give them a short walk to wake them up. A quick tip: administer the pill with a small amount of peanut butter to mask the taste.

• Case study: A 30‑lb terrier with pollen allergy improved after 4 weeks of 1 mg/kg dosing.
• Stat: 78% of dogs on Benadryl report reduced itching with no serious adverse events.

Zyrtec (Cetirizine)

Zyrtec is prized for its lower sedative profile compared to Benadryl. The recommended dose is 0.2 mg/kg once daily, usually given in the morning.

Side effects are mild: occasional somnolence and mild gastrointestinal upset. If your dog experiences nausea, offer a bland diet for a day.

• Real‑world example: A 45‑lb golden retriever began showing clearer skin after 2 weeks on Zyrtec.
• Data point: 65% of owners reported improved skin condition within the first month.

Prednisone

Prednisone is a powerful corticosteroid used for severe inflammation or autoimmune triggers. Dosage ranges from 0.5–2 mg/kg daily, depending on the condition severity.

Long‑term use can cause weight gain, polyuria, and immunosuppression. Always taper off gradually to avoid rebound inflammation.

1. Step 1: Start at 1 mg/kg for 1–2 weeks.
2. Step 2: Reduce by 0.5 mg/kg every week until maintenance.
3. Step 3: Stop when symptoms resolve.

Research shows a 12% increase in skin infections with prolonged prednisone therapy.

Fexofenadine

Fexofenadine offers a low‑sedation alternative. The typical dosage is 0.5 mg/kg once daily. Dogs often tolerate it well, with only mild gastrointestinal upset reported.

Use the same oral syringe method as for Benadryl to ensure accurate dosing. A useful tip: mix the liquid form with a small portion of canned food.

• Evidence: 72% of dogs on fexofenadine reported itch reduction within 48 hours.
• Comparison: Fexofenadine has a 30% lower incidence of dry mouth than Benadryl.

Lokivetmab (Cytopoint)

Lokivetmab is a monoclonal antibody that targets IL‑31, the itch mediator. It’s administered subcutaneously at 2 mg/kg every 4 weeks.

Side effects are rare, but injection site reactions occur in about 3% of dogs. A quick troubleshooting tip: warm the injection area beforehand to reduce discomfort.

• Case evidence: A 25‑lb poodle’s itching dropped from 8/10 to 2/10 after the first dose.
• Clinical trial: 94% of dogs achieved significant pruritus reduction within 2 weeks.

When deciding among these options, consider the severity of your dog’s symptoms, their medical history, and how quickly you need relief. Use the table and the tips above to guide your discussions with your vet and to make an informed, data‑driven choice for the best allergy meds for dogs that balances efficacy, safety, and cost.

4. Non‑Prescription Alternatives: Natural and Home Remedies

Why Go Natural? The Data on Dog Allergies

In the United States, over 60 % of dogs experience seasonal itching or skin flare‑ups, according to the American Veterinary Medical Association. Many owners turn to natural products to reduce these symptoms without heavy medication use.

Natural remedies can complement prescription drugs, but they are not a direct replacement when severe inflammation or systemic allergy triggers are present.

Omega‑3 Fatty Acids: The Real‑World Numbers

Clinical trials show that supplementing a dog’s diet with fish‑oil-derived omega‑3s reduces itching by 30‑40 % over a 12‑week period. The key is the EPA/DHA ratio.

• Use a high‑grade fish oil capsule – 200 mg EPA + 150 mg DHA per 10 kg of body weight.
• Swallow with a meal to improve absorption and avoid fishy burps.
• Monitor weight; omega‑3s can increase appetite slightly.

Hypoallergenic Diets: Step‑by‑Step Implementation

Food allergies account for up to 30 % of chronic itching cases. A hydrolyzed protein diet can eliminate antigenic triggers in such dogs.

1. Identify the suspect food through an elimination trial lasting 4‑6 weeks.
2. Switch to a commercial hypoallergenic formula; avoid soy, corn, and wheat if possible.
3. Reintroduce foods one at a time, observing for flare‑ups.

Follow the vet’s guidance on protein and fat levels to maintain optimal body condition.

Herbal Supplements: Evidence‑Based Choices

Several botanicals have shown anti‑inflammatory effects in canine skin studies. Quercetin, a flavonoid, can reduce histamine release by up to 25 % in vitro.

• Standard dose: 1 mg/kg per day, divided with meals.
• Combine with vitamin E for synergistic antioxidant support.
• Watch for mild GI upset; start with half the dose.

Topical Natural Options: Immediate Relief

A soothing aloe vera gel or coconut oil can calm irritated skin. Both have anti‑microbial properties that help prevent secondary infections.

• Apply a thin layer to affected areas twice daily.
• Check for allergic reactions; discontinue if redness worsens.
• Use only 100 % pure, pet‑safe products.

Integrating Natural Remedies with Medications

When using prescription antihistamines or corticosteroids, consider adding omega‑3s and a hypoallergenic diet to lessen drug dosage over time.

Example protocol: start with 5 mg/kg of Benadryl once daily while adding 0.3 mg/kg of fish oil. Reevaluate after 8 weeks; if itching improves, gradually reduce the Benadryl dose.

Always consult your veterinarian before mixing supplements with prescription drugs to avoid interactions.

Practical Tips for Owners

Record each supplement’s start date, dosage, and any changes in symptoms. A simple spreadsheet or pet‑health app can track progress.

• Set reminders for monthly re‑evaluation.
• Keep a symptom diary: itching, scratching, or skin lesions.
• Share data with your vet to adjust the treatment plan.

By combining evidence‑based natural approaches with conventional therapy, you can achieve a balanced, effective allergy management plan for your dog.

5. Expert Tips for Safe Administration

1. Verify Dosage with Your Veterinarian

Even common OTC allergy drugs can be fatal if mis‑dosed. A typical mistake is rounding the weight to the nearest pound, which can skew the mg/kg calculation by 10–20 %.

Use a reliable veterinary calculator or ask your vet to double‑check the dose before the first administration. For instance, a 30‑kg dog needs 30 mg of diphenhydramine, not 20 mg.

Keep a printed dosing chart in the clinic or as a phone note to avoid accidental over‑ or under‑dosing.

2. Monitor for Side‑Effects

Track your dog’s behavior in a simple log: activity level, appetite, and any itching changes. Record each entry at the same time daily for consistency.

According to a 2023 survey of 1,200 pet owners, 18 % reported mild sedation after a single dose of Benadryl. Early detection helps you adjust the dose or switch meds.

If you notice symptoms like choking, seizures, or swelling, stop the medication immediately and call your vet for emergency care.

3. Use a Timed Feeding Schedule

Most antihistamines work best when given 15–30 minutes before a meal. This timing reduces the chance of nausea and improves absorption.

For drugs labeled “take with food,” feed a small portion of plain rice or boiled chicken to soothe the stomach. Avoid fatty treats that may interfere with drug metabolism.

If your vet prescribes a corticosteroid, follow the same routine to maintain a steady blood level and prevent cortisol spikes.

4. Create a Medication Routine

Dogs thrive on routine, so set a consistent time each day for drug administration. Use a pill dispenser or a treat‑timed routine to reinforce compliance.

Consider a digital reminder on your phone or a smartwatch app linked to your pet’s medication schedule.

Consistency reduces the likelihood of missed doses, a common issue cited by 34 % of owners in a recent pet‑care study.

5. Store Medications Properly

Keep all allergy meds in a cool, dry place out of reach of children and other pets. Temperature fluctuations can degrade the active ingredients.

Use child‑proof pill organizers to prevent accidental ingestion by other animals.

Check expiration dates monthly; expired meds may be less effective or harmful.

6. Combine with Natural Supports Wisely

Omega‑3 supplements can reduce inflammation by up to 25 %, according to a 2022 veterinary nutrition review.

Use a 1:10 fish‑oil to dog‑food ratio for a 15‑kg dog, and give it at the same time as the allergy medication.

Always discuss any supplements with your vet to avoid drug‑supplement interactions.

By following these actionable steps, you’ll help your dog safely navigate allergy treatment while maximizing relief and minimizing risks.

Frequently Asked Questions About Dog Allergy Meds

What are the most common side effects of Benadryl in dogs?

Benadryl (diphenhydramine) can cause mild drowsiness in 20–30 % of dogs.

Other frequent symptoms include dry mouth, increased heart rate, and occasional gastrointestinal upset.

Severe reactions—such as seizures or difficulty breathing—occur in less than 1 % of cases.

• Watch for excessive sleepiness or lethargy after the first dose.
• Contact a vet if you notice vomiting, tremors, or wheezing.

Can I give my dog Zyrtec for seasonal allergies?

Zyrtec (cetirizine) is a popular OTC choice for seasonal allergies in dogs.

Studies show a 75 % reduction in itching when used at the recommended dose of 0.2 mg/kg daily.

Always confirm the correct weight-based dose with your veterinarian.

1. Weigh your dog accurately.
2. Calculate the dose (e.g., a 25‑lb dog needs ~0.2 mg/kg = 0.9 mg).
3. Administer with food to minimize stomach upset.

Is it safe to use prednisolone for long‑term allergy control?

Chronic prednisolone therapy can lead to weight gain in up to 40 % of dogs.

Long‑term use may also suppress the immune system, increasing infection risk.

Veterinarians often recommend a tapering schedule and regular bloodwork.

• Consider alternative agents such as Fexofenadine if side effects arise.
• Schedule quarterly wellness exams while on steroids.

What is Lokivetmab and how does it work?

Lokivetmab (Cytopoint) is a monoclonal antibody targeting IL‑31, the itch‑driving cytokine.

Clinical trials show a 60 % decrease in pruritus severity within 48 hours.

An injection of 2 mg/kg subcutaneously lasts approximately four weeks.

1. Get a baseline skin assessment before the first injection.
2. Monitor for rare injection site reactions—redness or swelling.
3. Plan the next dose around the 28‑day mark for continuous relief.

Can I combine antihistamines with other allergy medications?

Combination therapy can enhance relief but increases interaction risk.

Common pairings include an antihistamine plus a low‑dose steroid or a topical anti‑itch cream.

Always discuss combinations with your vet to avoid over‑medication.

• Example: Benadryl + Fexofenadine may double antihistamine coverage.
• Example: Cetirizine + a glucocorticoid ointment for localized flare‑ups.

How long does it take for allergy meds to start working?

Oral antihistamines typically provide itch relief within 30 minutes to 2 hours.

Corticosteroids usually require 24–48 hours for full anti‑inflammatory effects.

Biologic agents like Lokivetmab show noticeable improvement within 48 hours.

• Keep a symptom diary to track onset and duration of relief.
• Adjust dosing intervals if relief wanes before the next scheduled dose.

Are there any natural supplements that help with dog allergies?

Omega‑3 fatty acids (EPA/DHA) have been shown to reduce inflammation by up to 30 %.

Quercetin, a natural antihistamine, can alleviate itching when dosed at 10 mg/kg daily.

Vitamin E supports skin barrier function, especially in dogs with chronic dermatitis.

1. Start with a high‑quality fish oil supplement (1,000 mg EPA/DHA per 10 lb).
2. Introduce quercetin gradually to monitor tolerance.
3. Combine with a balanced diet low in potential allergens.

What should I do if my dog has an allergic reaction to a medication?

Immediately discontinue the suspected drug and rinse the area with cool water.

Call your veterinarian or an emergency animal hospital right away.

Prepare to administer an emergency antihistamine (e.g., diphenhydramine) if instructed.

• Keep a record of the medication name, dose, and time given.
• Note any accompanying symptoms such as swelling, vomiting, or labored breathing.

Can I use human allergy meds on my dog?

Only specific human meds are safe for canine use—no generic “take what your dog” approach.

Human antihistamines can be toxic if dosed incorrectly.

Always verify with a vet before giving any human medication.

• For example, diphenhydramine is safe at 1–2 mg/kg, but other ingredients may be harmful.
• Never give over‑the‑counter cold or flu blends; they contain decongestants harmful to dogs.

Is there a difference between a dog’s allergy meds and cat allergy meds?

Yes—dogs and cats metabolize drugs differently, affecting dosage and safety.

Formulations for cats often contain lower concentrations and different excipients.

Using dog medication on a cat can lead to toxicity or ineffective treatment.

• Always label medications by species to avoid mix‑ups.
• Consult your vet when switching between pet species for allergy care.

Conclusion

Choosing the best allergy meds for dogs is a decision that blends science, observation, and routine care. By decoding your pet’s signs and pairing that knowledge with a vet’s expertise, you create a roadmap to relief.

Step 1: Map Your Dog’s Symptom Timeline

Start by charting when itching peaks, what triggers flare‑ups, and how long relief lasts after each dose. A simple spreadsheet or an app can capture:

• Morning vs. evening itching.
• Outdoor exposure vs. indoor allergens.
• Duration of relief after antihistamine.

These data points guide dose adjustments and help differentiate between seasonal allergies and chronic atopic dermatitis.

Step 2: Compare Drug Classes with Real‑World Evidence

Clinical studies show:

• Benadryl reduces itching in 70% of dogs within 30 minutes.
• Lokivetmab offers 80–90% itch reduction for up to 28 days.
• Prednisone’s anti‑inflammatory effect peaks within 24–48 hours but carries a 15% risk of weight gain after 2 weeks.

Use these figures to weigh quick relief against long‑term safety.

Step 3: Tailor Dosage to Weight and Health Status

Always calculate mg/kg rather than using a one‑size‑fits‑all bottle. For example:

1. For a 20 kg dog: Benadryl 1 mg/kg → 20 mg per dose.
2. For a 10 kg dog on Lokivetmab: 2 mg/kg → 20 mg subcutaneously.

Ask your vet to verify the exact milligram count before purchasing.

Step 4: Monitor and Document Side Effects

Keep a symptom diary for at least 48 hours after each medication change. Record:

• Behavioral changes (drowsiness, agitation).
• Gastrointestinal signs (vomiting, diarrhea).
• Any new allergic reactions.

Report findings promptly; early detection can prevent complications.

Step 5: Integrate Natural Supplements When Appropriate

Omega‑3 fatty acids at 20–25 mg/kg/day can reduce inflammation and improve skin barrier function. Combine this with antihistamines only after vet approval to avoid drug interactions.

Step 6: Maintain Open Vet Communication

Schedule quarterly check‑ins to reassess medication efficacy and side‑effect profile. During each visit, discuss whether a switch to a biologic or a dose taper is warranted.

Practical Checklist for Pet Owners

• Track symptoms and medication timing.
• Calculate accurate dosages.
• Use a diary to note side effects.
• Incorporate supplements under vet guidance.
• Schedule regular vet visits.

Following this structured approach ensures your dog receives the best allergy meds for dogs safely and effectively.

Curious about the latest advances in canine allergy therapy? Dive deeper into our comprehensive guide to allergy management for dogs.