Good morning, and TGIF! Welcome back to Dr Euan's ENT blog!
For today's blogpost topic, we are going to look more closely into a problem that faces all of us living in SINGAPORE and the TROPICS: House Dust Mites.
Dust Mites can trigger allergic reactions in a large portion of the population in Singapore. So how should we go about keeping them out of our beddings, carpets, and stuffed toys?
Read on if you would like to find out more!
For how to manage dust mite allergies, you can read Dr Euan's previous blogpost on the topic here.
Q: What Are Dust Mites?
Dust mites are very small, insect-like pests that feed on dead human skin cells and thrive in warm, humid settings. Dust mites are too small for us to see. They are not parasites that bite, sting or burrow into our bodies. Instead, people who are allergic to dust or dust mites are reacting to inhaling proteins in dust that comes from dust mite feces, urine, or their decaying bodies. Any swelling (also called inflammation) of the nasal passages caused by dust mites is considered a dust allergy.
Dust mites can live in the bedding, mattresses, upholstered furniture, carpets, or curtains in your home. Dust mites are nearly everywhere; roughly four out of five homes in the United States have dust mite allergens in at least one bed.
Example image of a dust mite commonly found in carpeting
Q: HOW MANY TYPES OF DUST MITES ARE THERE?
The currently known species are:
Dermatophagoides farinae (American house dust mite)
Dermatophagoides pteronyssinus (European house dust mite)
Dermatophagoides evansi.
Dermatophagoides microceras.
Dermatophagoides halterophilus.
Dermatophagoides siboney.
Dermatophagoides neotropicalis.
Dermatophagoides alexfaini.
There are at least 13 species described.
In Singapore, we also have the BLOMIA TROPICALIS!
Q: Where do Dust Mites live?
Dust mites occur naturally and can appear in nearly all homes. Humidity is the most important factor in determining whether a house has high levels of dust mites. This is because dust mites do not drink water like we do; they absorb moisture from the air. In areas with low humidity, like deserts, dust mites cannot survive.
Unlike pet allergens, dust mite allergens do not usually stay in the air. Instead, the allergen settles quickly into dust or fabrics. These allergens cling to bedding, mattresses, upholstered furniture, carpets, and curtains, which also serve as nests. Most exposure to dust mite allergens occurs while sleeping.
Q: How do Dust Mite allergens affect our health?
Dust Mites are one of the major indoor triggers for people with asthma, sinusitis (or sinus), and allergic rhinitis.
Ongoing exposure to dust mites at home can impact the health of people with asthma and those who are allergic or sensitive to mites. These allergens can trigger mild to severe allergic symptoms and can be responsible for asthma attacks. A mild case may cause an occasional runny nose, watery eyes and sneezing.
In severe cases, the condition is ongoing, resulting in persistent sneezing, cough, congestion, facial pressure, or even a severe asthma attack. People with asthma who are sensitive to dust mites face an increased risk of asthma attacks.
Q: What are the symptoms of Dust Mite allergies?
Dust Mite droppings can trigger allergies causing symptoms like runny and blocked nose
Common dust mite allergy symptoms include:
Sneezing
Runny nose
Itchy, red, or watery eyes
Stuffy nose
Itchy nose, mouth, or throat
Itchy skin
Postnasal drip (a flow of mucus from behind your nose into your throat)
Cough
If your dust mite allergy triggers your asthma, you may also experience:
Difficulty breathing
Chest tightness or pain
A whistling or wheezing sound when breathing out
Trouble sleeping caused by shortness of breath, coughing, or wheezing
Q: How do we diagnose/confirm Dust Mite allergies?
To diagnose a dust mite allergy, your doctor may give you a physical exam and discuss your symptoms. If your doctor thinks you have a dust mite allergy, they may suggest a skin or blood test. If you have symptoms year-round, you could have a dust mite allergy.
Skin Prick Allergy testing can determine your sensitivity to allergens such as dust mites
Skin Prick Test (SPT) In prick/scratch testing, a small drop of the possible allergen is placed on your skin. Then the nurse or doctor will lightly prick or scratch the spot with a needle through the drop. If you are allergic to the substance, you will develop redness, swelling, and itching at the test site within 20 minutes. You may also see a wheal. A wheal is a raised, round area that looks like a hive. Usually, the larger the wheal, the more likely you are to be allergic to the allergen.
A positive SPT result for a particular allergen does not necessarily mean you have an allergy. Healthcare providers must compare the skin test results with the time and place of your symptoms to see if they match.
Specific IgE Blood Test Blood tests are helpful when people have a skin condition or are taking medicines that interfere with skin testing. They may also be used in children who may not tolerate skin testing. Your doctor will take a blood sample and send it to a laboratory. The lab adds the allergen to your blood sample. Then they measure the amount of antibodies your blood produces to attack the allergens. This test is called Specific IgE (sIgE) Blood Testing. This was previously commonly referred to as RAST or ImmunoCAP testing. As with skin testing, a positive blood test result for an allergen does not necessarily mean that an allergen caused your symptoms.
If you would like to know more about the allergy testing and management options we provide at Euan's ENT Surgery & Clinic, please have a read here.
Q: How can we Reduce Dust Mites at home?
You can take action to reduce dust mites in your home.
Reduce humidity. Keep your home below 50 percent humidity. In humid areas, air conditioning and dehumidifiers can help.
Reduce the places where dust mites can live. Remove upholstered furniture or use furniture with smooth surfaces. Remove drapes and curtains. Cover mattresses and pillows with allergen encasements. Wash bedding in hot water (at least 120 degrees F) once a week. Reduce clutter, stuffed animals, and other places where dust mites live. If that’s not possible, wash stuffed animals weekly in hot water (at least 130 degrees) to kill and wash away dust mites.
Replace carpets. Carpeting should be removed from the home, especially if occupants are allergic to dust mites. If you must keep the carpet, use a vacuum cleaner with a HEPA (High-Efficiency Particulate Air) filter. Damp clean floors often, focusing on catching dirt and dust without wet mopping.
Dust regularly. Dust regularly to reduce the amount of dust and improve overall indoor air quality in your home. When dusting, use something that can trap and lock dust (like a wet washcloth or microfibre cloth) dust to reduce the amount of it that is stirred up when cleaning.
Use Air filtration devices and purifiers. Using a “High Efficiency Particulate Arrester” or HEPA filter, can remove up to 99.7% of particles in the air as small as 0.3 micrometers in size.
Get Mite-proof mattresses and pillow covers. Use allergy covers for your mattress, pillows, and comforters to minimise allergen exposure.
Regular cleaning with a HEPA vacuum cleaner. Using a HEPA vacuum can be useful in decreasing the amount of allergens at home. HEPA vacuum cleaners are special designed to filter dust, pet dander and pollen out of floors, rugs and carpeting.
Check your air-con filters periodically. A dirty filter on an air conditioning unit can keep air from flowing the way it should. Change it at least every 3 months and make sure it fits well. You might want to check it once a month. It’s also a good idea for a professional to inspect the unit once a year.
People with allergies to dust mites or with asthma triggered by dust mite allergies should try to reduce dust mites in their home.
Example of an air filtration device that can be helpful in reducing allergens in the air and environment
Q: HOW CAN WE TREAT DUST MITE ALLERGIES?
The most important step is to avoid dust mites as much as possible. Limiting your exposure to dust mites will reduce your symptoms. However, it’s nearly impossible to completely get rid of dust mites in your environment. You may also need medicines to control symptoms.
Medicated nasal sprays can help to reduce decongestion and alleviate allergy symptoms
Certain over-the-counter and prescription medicines may help reduce dust mite allergy symptoms.
Antihistamines are available as pills, liquids, or nose sprays. They can relieve sneezing and itching in the nose and eyes. They also reduce a runny nose and, to a lesser extent, nasal stuffiness.
Nasal corticosteroids are a type of nose spray. They reduce swelling in your nose and block allergic reactions. They are the most effective medicine type for allergic rhinitis because they can reduce all symptoms, including nasal congestion. Nasal corticosteroids have few side effects.
Leukotriene receptor antagonists block the action of important chemical messengers (other than histamine) involved in allergic reactions.
Cromolyn sodium is a nose spray that blocks the release of chemicals that cause allergy symptoms, including histamine and leukotrienes. This medicine has few side effects, but you must take it four times a day.
Decongestants are available as pills, liquids, nose sprays or drops. They help shrink the lining of the nasal passages and relieve stuffiness. Use decongestant nose drops and sprays only for a short time. Oral decongestants can cause side effects such as sleeplessness and increased blood pressure in some people. Consider checking with your doctor before using them.
For Dr Euan's advice on taking nasal sprays, please have a read here.
Many people with a dust mite allergy do not get complete relief from medicines. This means they may consider immunotherapy (allergy shots). Immunotherapy is a long-term treatment that can help prevent or reduce the severity of allergic reactions. It can reduce the course of allergic disease by changing your body’s immune response to allergens.
Allergy Shots – subcutaneous immunotherapy (SCIT) is an effective treatment that has been around for more than 100 years. SCIT is a series of shots that have progressively larger amounts of allergen. An injection of the allergen goes into the fat under your skin about once a week during the initial phase of treatment. Many patients get complete relief of their allergies after being on SCIP for one to three years. Many physicians will continue SCIT for a period of five or more years. SCIT can provide long-lasting symptom relief. Many people experience benefits for at least several years after the shots stop.
Sublingual (under-the-tongue) immunotherapy (SLIT) is a way to treat dust mite allergies without injections. Patients put small doses of an allergen under the tongue. This exposure improves tolerance to the dust mites and reduces symptoms. SLIT tablets that treat dust mite allergy were approved by the FDA in 2017.
Immunotherapy can alter the body's immune response to allergies in the long term
Well, I do hope this post has given you some insight into the incredible and complex problems these tiny creatures known as dust mites can bring to us humans!
Here are some references for more in-depth reading; ENJOY!
Have a great weekend!
Dr Euan
If you would like to consult an ENT specialist about dust mite allergies, or any other Ear, Nose, or Throat related conditions, please feel free to Contact Us at Euan's ENT Surgery & Clinic to make an appointment.
Clinic Contact No. : 6694 4282
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