How Bedbugs Make Asthma Worse

Medically Reviewed By William C. Lloyd III, MD, FACS
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Close-up of bed bug on pink knit fabric

Bedbugs—tiny nocturnal insects that feed on the blood of sleeping animals or humans—are unfortunately common. Many people develop itchy red welts at the site of a bedbug bite. These bites are uncomfortable and unsightly, but they aren’t a health hazard; bedbugs do not transmit disease.

People with asthma, though, may experience increased asthma symptoms if exposed to bedbugs. Experts think bedbugs (and their waste material) trigger an allergic reaction in some people. These people are more likely to develop intense itching, swelling and large welts at bite sites. People with a bedbug allergy and asthma may experience asthma attacks as a result of exposure.

Learn more about how bedbugs affect asthma and how to effectively manage asthma and bedbugs.

Bedbugs 101

An estimated 1 out of 5 Americans either has had a bedbug infestation or knows someone who has, according to an article published in Clinical Microbiology Reviews. These pests are often found in bedrooms, but they can thrive in almost any upholstered environment where humans sit or sleep, including movie theatre recliners and train seats.

Because bedbugs are tiny (about the size of an apple seed) and hide in crevasses when they’re not feeding, most people will never see a live bedbug, even if their home is infested. Usually, people notice the symptoms of a bedbug infestation first: itchy red bite marks that appear in the morning, often in a line.

Bedbugs also leave behind evidence. If you look closely at the cracks and crevasses of an infested mattress, you may be able to see collections of tiny black specks (bedbug poop) and rusty or reddish stains (basically, squashed bedbugs). You might also see eggs and discarded insect skins, as well as live bedbugs.

The link between asthma and bedbugs may be histamine.

Bedbugs can trigger asthma if a large group of them (or their waste materials) becomes airborne. Research is beginning to reveal exactly why bedbug exposure may lead to worsening asthma.

Bedbug feces contains a large amount of histamine, a chemical that can trigger allergic reactions, including narrowing of the airways. A 2018 research study revealed high indoor levels of histamine in homes with bedbug infestations and only trace levels of histamine in homes known to be bedbug-free. Respiratory exposure to histamine can reduce forced expiratory volume (basically, a measure of lung capacity at any given moment)—and people with asthma appear particularly sensitive to its effects.

Bedbug control may improve asthma symptoms.

If you or your child has asthma, you may be able to prevent some asthma attacks by maintaining a bedbug-free environment.

Here’s how:

  • Look for evidence of bedbug infestation. Note: If you have asthma, it’s probably best not to undertake this task yourself. Ask a friend to help you or hire a pest control expert. Remember, bedbugs leave behind tiny black spots, rusty stains and discarded yellow to reddish insect skins.

  • Eradicate bedbugs.Exposure to heat or cold can kill bedbugs. To effectively get rid of bedbugs, you must treat every object or location in which they’re present, which may include mattresses, pillows, box springs, clothing, rugs or furniture. Smaller items can be placed in an electric dryer set to high for 20 minutes. Larger items may be best treated by a professional.

  • Encase mattresses and box springs.To prevent and treat bedbug infestation of mattresses and box springs, you can simply purchase and apply zippered covers. These covers can prevent bedbugs from making a home of your bed and are an easy, cost-effective way to eliminate bedbugs. (The cover traps the insects inside, so they can’t feed. Eventually, they die.)

You may also want to consider using a portable air cleaner in the bedroom. Histamine levels remain high in bedbug-infested areas even three months after bedbug removal. An air cleaner can reduce airborne allergens and may reduce your histamine exposure.
People who have asthma and are allergic to bedbugs will likely breathe easier in a bedbug-free environment.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2021 Jun 3
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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