Can allergies make your blood pressure go up

• August 1, 2022
• Rx Newsletter

Adults with a history of allergies have an increased risk of coronary heart disease.

A new study used 2012 data from a cross-sectional survey of the U.S. population. The allergic group included adults with at least 1 allergic disorder, including but not limited to asthma, respiratory allergies, digestive allergies, and skin allergies. The study included around 35,000 adults with an average age of 48.5 years and more than half of whom were women. The researchers found that individuals with a history of allergies between the ages of 18 and 57 had an increased risk of developing high blood pressure and coronary heart disease. “For patients with allergic disorders, routine evaluation of blood pressure and routine examination for coronary heart disease should be given by clinicians to ensure early treatments are given to those with hypertension or coronary heart disease,” elaborated Yang Guo, PhD, and the study’s lead author.1

Previous studies have reported an association between allergies and cardiovascular disease, but these findings had remained controversial. Long-term follow-ups alongside large cohort studies will be needed to confirm the findings. However, knowing that allergies may be an underlying cause of high blood pressure and heart disease may help management of these disease in individuals in the future.

How do allergies contribute to high blood pressure?  

There are a few theories on how allergies contribute to high blood pressure. When an allergen triggers an allergic response, histamines in the body boost blood flow into the area that the allergen attacks. This causes the immune system to send antibodies to that area, triggering inflammation. Inflammation is the body’s natural way of fighting off allergens and pathogens. Science shows that a long-lasting inflammatory response is an underlying factor in many chronic diseases including diabetes, high blood pressure, and heart disease.

Many allergy medications are antihistamines, which counter the body’s inflammatory response. Antihistamines and pseudoephedrine (also found in many allergy medications), constrict blood flow by narrowing the blood vessels in the body. These narrow blood vessels can also lead to high blood pressure and increased heart rate. Another medication often prescribed for allergies or asthma is steroids. Steroids increase both blood pressure and blood sugar. Having high blood pressure and high blood sugar are important risk factors for coronary artery disease and stroke.2

In addition, nasal congestion associated with many allergy disorders may interfere with breathing while sleeping. Nasal congestion may promote or worsen sleep apnea. People with sleep apnea have an increased risk of high blood pressure. About 50% of sleep apnea patients have hypertension. Sleep apnea can also contribute to poor quality of sleep and shorter periods of sleep, which can raise someone’s blood pressure.3

Sources:

• Katie Glenn. “History of Allergies May Be Associated with Increased Risk of High Blood Pressure, Heart Disease”, available at History of Allergies May Be Associated with Increased Risk of High Blood Pressure, Heart Disease – American College of Cardiology (acc.org)
• Harvard Health Publishing. “Ask the doctor: Can allergies cause high blood pressure?”, available at Ask the doctor: Can allergies cause high blood pressure? – Harvard Health
• Alexa Fry. “How Sleep Apnea Affects Blood Pressure”, available at How Sleep Apnea Affects Blood Pressure | Sleep Foundation

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Spring brings warmer temperatures, blooming flowers and, for millions of Americans, the arrival of allergy season. It also coincides this year with the arrival of COVID-19, which could make allergy sufferers hyperaware of every sneeze and sniffle.

But there are key differences in symptoms. Seasonal allergies can cause sneezing, runny nose, itchy eyes and cough. Yet unlike allergies, coronavirus causes a fever, with other symptoms including cough and shortness of breath.

When seeking relief, people with allergies who are concerned about heart disease or high blood pressure must be especially careful when taking blood pressure-raising, over-the-counter decongestants. They're also stimulants, which can increase heart rate.

But determining the extent of the direct connection between allergies and heart health is a topic that needs more research. A look at two studies offers examples of differing conclusions.

A 2016 study in the American Journal of Epidemiology examined the relationship between airborne allergen concentrations and emergency room visits for heart attacks in Ontario, Canada, from 2004-2011. The study found the risk of having a heart attack was 5.5% higher on days with the highest pollen levels compared to days with the lowest levels. Heart attack risk was highest in May and June, when tree and grass pollen are most common.

"There appears to be an association between seasonal allergies and cardiovascular health," said Dr. Laurence Sperling, the Katz Professor in Preventive Cardiology at Emory University School of Medicine in Atlanta. "This is an area where further investigation is needed."

The results contrast to findings from another 2016 study in the Annals of Allergy, Asthma and Immunology, which found patients with physician-diagnosed allergic rhinitis, or hay fever, had a significantly lower risk for heart attack than patients without hay fever. That study looked at Kaiser Permanente Southern California patients from 1999-2012.

"Other allergic conditions such as asthma have been shown in several studies to have an increased risk of cardiovascular disease, so it was a little surprising to us that we found this association," said Dr. Angelina Crans Yoon, the study's lead author. "We thought frankly it would be the opposite."

Crans Yoon, an allergist and immunologist, said patients were still more likely to have high blood pressure, despite a smaller chance for heart attack. "Since then, a couple other studies have come out that kind of show a similar association," she said.

One potential reason for her study's findings, she said, was patients with hay fever had more frequent visits to the doctor, which could lead to more blood pressure screenings. In turn, that could lead to a patient being prescribed medication to reduce high blood pressure.

Like Sperling, Crans Yoon said the topic overall needs more research. Risk factors for cardiovascular disease can build over time, so even studies that follow patients for more than a decade may not capture a complete picture.

And her advice for patients still hasn't changed.

"It's not that having the allergies or suffering through it makes you stronger or anything like that," said Crans Yoon, of Dignity Health Medical Foundation in Davis, California.

"Working to reduce your cardiovascular risk factors – eating a healthy diet, exercising and getting enough sleep – all those things that are important for your overall health are still very important whether you have allergies or not," she said.

Other general tips for allergy sufferers:

– Keep doors and windows closed and run the air conditioner during pollen season.

– Change clothes and take a shower after being outside.

– Antihistamines can help clear congestion and are safer for the heart than decongestants.

"Individuals with high blood pressure or known heart disease should be cautious with, or avoid, decongestants," Sperling said. "It is always a good idea to check with your doctor before taking an over-the-counter medication for seasonal allergies."

Seeing a physician or allergist can also help people identify allergy triggers, Crans Yoon said, which can help allergy sufferers reduce exposure and anticipate when to take medication.

If you think you have more than just allergies, contact your physician and follow guidelines from the Centers for Disease Control and Prevention about what to do if you suspect you have or have been exposed to COVID-19.

Editor's note: Because of the rapidly evolving events surrounding the coronavirus, the facts and advice presented in this story may have changed since publication. Visit Heart.org for the latest coverage, and check with the Centers for Disease Control and Prevention and local health officials for the most recent guidance.

If you have questions or comments about this story, please email [email protected].

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