November 19, 2020

Why Asthma Puts You at Greater Risk This Flu Season

Infections, like the flu, are a common asthma trigger

asthma and flu check using spirometer

If you have asthma, flu season may come with a lot of anxiety. People with asthma, even a mild case, are more likely to get serious flu complications.


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But you’re not powerless this flu season. Pulmonologist Nirosshan Thiruchelvam, MD, explains how to protect yourself and stay healthy.

Why flu is an asthma trigger

If you have asthma, you probably already know your triggers (and how to avoid them). Triggers are the things that make asthma flare-up, including:

  • Cigarette smoke.
  • Cleaning chemicals.
  • Dust mites.
  • Exercise.
  • Mold.
  • Pet dander.
  • Pollen.
  • Pollution.

But respiratory infections like the flu are major asthma triggers, too. A respiratory infection, whether it’s the flu or a cold, causes inflammation. And asthma is an inflammatory condition. Together, they deliver an inflammatory onslaught that can cause:

  • Shortness of breath.
  • Increased mucus and phlegm.
  • Coughing.
  • Wheezing.
  • Chest tightness

“Many viruses can trigger asthma, including rhinoviruses and coronaviruses, which cause respiratory infections,” says Dr. Thiruchelvam. “People with asthma can have a more severe illness from the virus. It also takes them longer to recover.”

Maybe you have asthma that’s mild and intermittent. You might think the flu isn’t a big deal. But that’s not the case. “Even if you only use your inhaler occasionally, you’ll still have more flu complications than someone without asthma,” Dr. Thiruchelvam explains. “This can be surprising to people who have mild or intermittent cases.”

Your peak flow can show early signs of trouble

Your peak expiratory flow meter can alert you to problems early during flu season. Dr. Thiruchelvam says that a reduction in peak flow of greater than 20 percent from normal, or from your personal best value, indicates the presence of an asthma exacerbation. Peak flow levels often drop when you come down with the flu — and even when you don’t feel sick. If your peak flow level is low, talk to your healthcare provider. Together, you can discuss management before the flu slams you with symptoms.


“The flu comes on suddenly,” Dr. Thiruchelvam explains. “You might feel fine in the morning, and by afternoon, you feel terrible. Even if you don’t think you’re sick, check your peak flow every day. If it’s low, talk to your doctor. Don’t wait until you notice a problem.”

Follow your asthma action plan

If you have asthma, you should have an asthma action plan. You and your doctor work together to create this plan, which tells you how to manage your asthma. It may include:

  • Asthma medications you take and when to take them.
  • Your triggers and how to avoid them.
  • Your normal peak flow numbers.
  • Symptoms to watch for.
  • Emergency contact numbers.

“Your asthma action plan is important every day, whether it’s flu season or not,” says Dr. Thiruchelvam. “Having your asthma under control gives you a better quality of life.”

Good asthma control is your weapon against flu complications. Good control means you won’t have inflamed, irritated lungs that are trying to battle a nasty flu bug.

You and your doctor should update your asthma action plan every 12 months. If you don’t have a current plan, get an updated one.

Flu prevention tactics

Take steps to reduce your chance of getting the flu. Protect yourself with these proven methods:

  • Flu shot: Everyone ages 6 months and older should get a flu shot every year. The vaccine reduces the risk of being hospitalized and dying from the flu. It’s essential if you have asthma.
  • Wash your hands: Wash your hands with soap and water before eating or preparing food. Wash them after going to the bathroom. Wash them after touching shared surfaces like doorknobs or ATMs. It’s OK to be a handwashing fanatic.
  • Hand sanitizer: When you can’t get to a sink, use hand sanitizer. Keep some in your pocket or purse at all times.
  • Pneumococcal vaccine: Ask your doctor if you’re up to date on this vaccine. It protects against pneumococcal pneumonia, a life-threatening flu complication.
  • Avoid crowds: Avoid crowded stores or large gatherings when possible. Lots of people can mean lots of chances to catch a bug like the flu.
  • Reschedule with sick friends and family: If you know someone is sick, even with just a cold, stay away until they’re better.

Flu, asthma and pregnancy

As if asthma and the flu weren’t enough on their own, pregnancy adds another factor into the mix. Some find that their asthma gets worse during pregnancy.

If you’re pregnant, tell your obstetrician about your asthma. Work with your doctors to keep it under control. And get your flu shot. It’s safe — and recommended — for pregnant people.

No fear this flu season

Flu complications can be serious, but there’s no need to panic. Take steps to protect yourself and stay on top of your asthma. With a little planning and a lot of hand washing, you can stay healthy throughout flu season and beyond.

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