Do Seasonal Allergies Cause Fever?
A lot of allergy sufferers wonder about this, especially as their allergy symptoms can seem like those of a cold or the flu. It’s easy to see why people are confused about this. After all, there are many ways in which these conditions can be closely related. We’ll cut through the confusion in this guide.
You’ll find out how to recognize allergic symptoms from real illnesses, why your immune system works the way it does and what you can do to avoid symptoms this season.
Symptoms of Seasonal Allergies
Allergens such as pollen, mold spores and dust mites are mostly responsible for seasonal allergies, better known as hay fever or allergic rhinitis, during both spring and fall.
Here are the most common symptoms:
✔ Sneezing fits
✔ Runny or stuffy nose (often clear mucus)
✔ Itchy, watery eyes
✔ Itchy throat or ears
✔ Postnasal drip
✔ Fatigue due to poor sleep or congestion
One key distinction? These symptoms usually last for weeks or even months if untreated and often follow a predictable seasonal pattern.
Causes of Seasonal Allergies
Seasonal allergies occur when your immune system overreacts to a typically harmless substance, like pollen, as if it were a threat.
Common seasonal allergens include:
✔ Tree pollen (spring)
✔ Grass pollen (late spring to summer)
✔ Weed pollen (late summer to fall)
✔ Mold spores (especially in damp or decaying leaves)
If your immune system detects these allergens, it releases histamine, which results in inflammation and the usual allergy symptoms such as sneezing and itching.
However, there’s a catch – this immune overreaction can lead to systemic effects, including low-grade inflammation. And that’s where fever enters the conversation.
Can Seasonal Allergies Cause a Fever?
Unlike with bacterial or viral infections, seasonal allergies usually do not result in a fever. Still, it’s important to know about a few special cases:
1. Secondary Infections
If your allergies cause congestion, the trapped mucus in your sinuses can result in a sinus infection (sinusitis). Most of the time, these infections cause fever, pain around the face and a feeling of pressure.
2. Immune Stress Reaction
Though this is unusual, severe allergies or persistent inflammation can slightly raise your body temperature, but it is not considered a fever unless it reaches 100.4°F / 38°C.
3. Allergy-Induced Fatigue
Allergy-related weakness and chills are sometimes mistaken for fever. Even if you feel out of sorts, your temperature is often normal.
Bottom Line: If you’re running a fever, it’s more likely caused by an infection, not seasonal allergies.
Allergies vs. Flu vs. Cold – Understanding the Difference
It’s easy to confuse seasonal allergies with a cold or the flu. Here’s a side-by-side comparison to help you spot the difference:
| Symptom | Allergies | Cold | Flu |
|---|---|---|---|
| Fever | Rare/None | Sometimes (low-grade) | Common (high fever) |
| Sneezing | Common | Common | Sometimes |
| Itchy eyes/nose | Very common | Rare | Rare |
| Cough | Sometimes | Common | Common and dry |
| Fatigue | Sometimes | Mild | Often severe |
| Onset | Sudden | Gradual | Rapid |
| Duration | Weeks/Months | 7–10 days | 1–2 weeks |
Still unsure? A healthcare provider can help you get an accurate diagnosis, especially if symptoms linger or worsen.
When to Worry: Warning Signs It’s Not Just Allergies
Most seasonal allergy symptoms are uncomfortable but manageable. However, some signs should prompt you to take action or seek medical advice – fast.
Warning signs your symptoms may be more than allergies:
✔ High fever (above 100.4°F / 38°C) that lasts more than a day or two
✔ Facial pain or swelling, especially around the cheeks, eyes, or forehead
✔ Thick yellow or green nasal mucus, which may indicate a bacterial infection
✔ Persistent cough, wheezing, or shortness of breath not relieved by allergy meds
✔ Fatigue so severe that it disrupts daily life
These could point to a sinus infection, respiratory illness, or even undiagnosed asthma – all of which require different treatments than seasonal allergies.
If symptoms appear suddenly or worsen quickly, especially with fever, don’t assume it’s just hay fever. Trust your instincts and consult a healthcare provider. At Juniper Allergy, we’re trained to help you differentiate and manage complex symptoms – because peace of mind starts with clarity.
How to Diagnose Seasonal Allergies
If you suspect seasonal allergies, the first step is confirming the cause, especially before assuming that a fever is part of the allergic reaction.
Diagnostic Tools Include:
✔ Allergy Testing: Skin prick or blood tests can pinpoint specific allergens.
✔ Symptom Tracking: Keeping a journal of your symptoms and when they occur (e.g., after mowing the lawn or during high pollen counts).
✔ Ruling Out Infection: A physical exam or lab tests can determine if a virus or bacteria is behind the symptoms.
If fever is involved, your doctor will likely explore non-allergic causes like viral infections or sinusitis.
Treatment of Seasonal Allergies (Short-Term & Long-Term)
Once diagnosed, managing seasonal allergies is completely possible, especially with a mix of immediate relief and long-term strategies.
Short-Term Relief
✔ Antihistamines (e.g., cetirizine, loratadine): Reduce sneezing and itching
✔ Nasal corticosteroids (e.g., fluticasone): Decrease inflammation in the nasal passages
✔ Decongestants (e.g., pseudoephedrine): Temporarily relieve nasal congestion
✔ Eye drops: Soothe itchy, red eyes
✔ Saline rinses: Clear the nasal passages of allergens and mucus
Note: Overusing nasal sprays or decongestants can lead to rebound symptoms. Follow your doctor’s guidance.
Long-Term Management
Allergy Immunotherapy (allergy shots or tablets): Gradually trains your immune system to tolerate allergens
Environmental Control:
✔ Check pollen forecasts
✔ Use air purifiers and HEPA filters
✔ Keep windows closed during high pollen days
✔ Shower and change clothes after being outdoors
Medication Maintenance: Taking allergy meds daily during peak seasons, not just when symptoms flare up
When to See an Allergist:
✔ If symptoms persist year-round
✔ If you’re experiencing recurring sinus infections or a suspected fever
Conclusion
So, do seasonal allergies cause fever? Not typically, but they can set the stage for secondary infections that do. If you’re experiencing fever alongside allergy-like symptoms, it’s crucial to consider other causes like colds, the flu, or sinus infections.
Understanding your body’s signals is the first step toward relief. With proper diagnosis and a tailored treatment plan, you can enjoy the changing seasons without the sneezing – and without the stress of mystery symptoms.
Think you might have seasonal allergies? Juniper Allergy is here to help with advanced diagnostics and personalised care plans that actually work.
Ready to Stop Guessing and Start Breathing Easier?
At Juniper Allergy, our team of allergists in San Antonio specialize in accurate diagnosis and personalized treatment, so you’re not stuck suffering all season long.
What we offer:
✔ Expert allergists
✔ Advanced allergy testing for pollen, dust, and mold sensitivities
✔ Long-term relief through customized care
Book your allergy consultation today and breathe easier tomorrow.