Can Allergies Cause High Blood Pressure?
Yes. Allergies can contribute to temporary increases in blood pressure, although they are not usually a direct cause of chronic hypertension. When your immune system reacts to allergens, it can trigger stress responses and congestion that make your heart work harder.
These effects are usually short-lived, but for some people, the combination of symptoms, stress hormones, and certain medications can create noticeable spikes. Understanding how allergies affect your body can help you prevent avoidable rises in blood pressure and manage symptoms more comfortably.
Allergies are extremely common in Australia and can show up as hay fever, dust sensitivity, pet reactions, mould irritation, or food triggers. For many people, they are an inconvenience, but for others, they significantly disrupt daily comfort and well-being. When symptoms flare up, your body releases chemicals such as histamine. This speeds up your heart rate, tightens your airway, and can make you feel tense. All of these reactions can raise blood pressure temporarily.
How Allergies Affect Your Blood Pressure
1. Stress on the Cardiovascular System
Allergy symptoms, such as blocked sinuses and difficulty breathing, can activate your sympathetic nervous system. This is the same system that responds to stress and can cause your heart to beat faster. When your heart rate increases, your blood pressure can rise too. This response helps your body cope with discomfort, but it can be more noticeable if you already have hypertension or anxiety.
2. Inflammation
Your immune system reacts strongly to allergens, producing inflammation in your nose, throat, and lungs. Although this inflammation is local, the immune response itself can trigger systemic effects that temporarily affect circulation.
3. Poor Sleep
If allergies disturb your sleep, your blood pressure can be affected the next day. Poor sleep is known to raise cortisol levels, which can lift blood pressure. Many Australians who deal with seasonal allergies report worse symptoms at night because pollen levels often rise after sunset.
4. Decongestant Medications
Medications that contain pseudoephedrine or phenylephrine can narrow blood vessels and sharply increase blood pressure. Many over-the-counter cold and allergy products include these ingredients. People with hypertension are usually advised to avoid them. Antihistamines, on the other hand, do not normally raise blood pressure.
At Juniper Allergy, we focus on identifying triggers so you can rely less on medications that cause unwanted side effects. A personalised assessment helps you understand what is driving your symptoms and how to manage them safely.
When You Should Be Concerned
If your blood pressure only rises during allergy flare-ups and returns to normal once symptoms settle, it is unlikely to be a serious problem. However, you should pay attention if:
✔ Your blood pressure is elevated even when allergy symptoms improve
✔ You regularly use decongestants and notice ongoing headaches or palpitations
✔ You have a history of hypertension and allergies, which make your readings worse
✔ You feel dizzy, breathless, or unusually fatigued
A GP can help rule out underlying issues, and an allergy specialist can guide you toward safe treatment options that do not compromise cardiovascular health.
If you want expert help identifying what is causing your symptoms, Juniper Allergy provides testing and personalised plans to support long-term relief.
Managing Allergies Safely When You Have High Blood Pressure
Choose the right medications
Antihistamines are usually safe for people with high blood pressure, but always check with your pharmacist or GP. Avoid decongestants unless recommended by a health professional.
Keep your home environment allergy-friendly
Regular vacuuming, air purifiers, washing bedding in hot water, and closing windows during high pollen hours can significantly reduce exposure.
Stay hydrated
Allergy symptoms often feel worse if you are dehydrated, and dehydration can influence blood pressure. Fluids help thin mucus and ease congestion.
Treat the root cause
Identifying specific allergens helps you target treatment rather than relying on short-term symptom relief. Allergy testing guides smarter long-term decisions.
The Way Forward
Juniper Allergy offers comprehensive testing and tailored management strategies to help Australians live comfortably without fear of sudden symptom flare-ups.
If allergies are affecting your comfort or making blood pressure management harder, book an appointment with Juniper Allergy today for personalised testing and treatment options.