Can seasonal allergies make you feel sick?

This blog is for educational purposes only and does not replace professional medical advice or diagnosis. If you have health concerns, consult an AHPRA-registered telehealth doctor or request a medical certificate online if clinically appropriate. Please note: Hola Health does not currently offer Mental Health Care Plans.

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Overview

Do you ever feel tired, run-down, or like you’ve caught a cold — only to realise it’s your allergies acting up? It’s completely real.
Seasonal allergies can make you feel unwell, not just sneezy and itchy. In fact, seasonal allergies affect up to 30% of Australians¹.

Let’s explore why allergies cause these symptoms and what you can do to feel better.

What are seasonal allergies?

Seasonal allergies, also known as hay fever or allergic rhinitis, occur when your immune system reacts to harmless particles in the air. Common Australian triggers include:

• Grass and tree pollen (especially in spring and summer)
• Dust and mould during humid seasons
• Certain weeds, such as ryegrass and wattle, which release large amounts of pollen

Hay fever is an immune reaction, not an infection².

Can seasonal allergies make you sick?

Yes, seasonal allergies can mimic cold or flu-like symptoms, making you feel under the weather. When your immune system reacts to allergens, it releases histamine, which causes swelling, fatigue, nasal blockage, and an overall “off” feeling.

Ongoing sneezing, sinus pressure, and poor sleep can worsen these symptoms, making allergies feel very similar to being sick.

Symptoms

Common symptoms of seasonal allergies include:

• Runny or blocked nose
• Sneezing
• Itchy or watery eyes
• Fatigue or ongoing tiredness
• Headaches or sinus pressure
• Mild sore throat caused by post-nasal drip
• Difficulty concentrating (“allergy fog”)
• Occasional coughing or wheezing, especially if you have
  asthma

Tip: Allergies do not cause fever — this is a key difference between allergies and
viral infections.

Why allergies cause fatigue and sickness-like feelings

Allergies can leave you feeling unusually tired and unwell because your immune system is working overtime, even though there is no real threat.

1. Immune overreaction: Your body releases histamine and other inflammatory chemicals, which can leave you feeling drained and low on energy.
2. Blocked sinuses: Congestion and sinus pressure restrict airflow and can cause a heavy-headed feeling.
3. Poor sleep: Night-time sneezing and nasal congestion can
   disrupt sleep, leading to daytime fatigue.
4. Dehydration: A runny nose and mouth breathing may cause mild dehydration, which can worsen tiredness.

Allergies vs Cold

Allergies and colds often share similar symptoms, which can make it hard to tell them apart. The table below highlights the key differences:

Symptom	Allergies	Cold/flu
Fever	No	Common
Itchy eyes	Common	Rare
Symptom duration	Weeks to months	7–10 days
Sneezing fits	Frequent	Occasional
Mucus colour	Clear	Yellow or green

If you’re unsure, consult an online GP – especially if symptoms last longer than expected. If your symptoms are preventing you from working, you can also easily request a sick certificate online while you rest.

Allergy Relief Tips

While allergies can leave you feeling drained, simple everyday strategies can help you breathe easier and feel more like yourself. Here are a few practical tips:

• Take antihistamines or nasal sprays as directed.
• Use saline rinses to clear nasal passages.
• Stay hydrated and get adequate rest.
• Keep windows closed during high-pollen days.
• Use air purifiers indoors.
• Avoid early mornings or windy outdoor activities, when pollen levels peak.
• Keep track of local pollen counts.

When to see a GP

You should see a GP if:

• Over-the-counter treatments don’t provide relief.
• Symptoms worsen or lead to sinus infections.
• You have asthma or breathing difficulties triggered by allergies.
• You’re unsure whether symptoms are due to allergies or illness.

How Hola Health can help

If you’re struggling with persistent allergy symptoms, Hola Health makes it easy to access expert care online with tailored treatment options.

• Get online telehealth consultations for allergy diagnosis and management.
• Get prescriptions for antihistamines, nasal sprays, or other allergy relief via eScript.
• Receive personalised allergy management plans based on your triggers and symptoms.
• Access care from anywhere in Australia — no waiting rooms or travel required.

Conclusion

Seasonal allergies can make you feel sick, even though they aren’t caused by an infection. With proper care and consistent management, symptoms can be controlled effectively. If allergies are making you feel constantly unwell, speak with a Hola Health GP online for expert advice and appropriate treatment options.