Welcome to the dust mite guide! I hope it empowers you to have healthier home and provide a healthier life for you and your loved ones.
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Wishing you energy, joy, and success on your journey.
Dust mites are a health crisis hiding in plain site. They are a major driver of allergic disease like asthma, allergic rhinitis, and eczema. If you have perennial asthma (for example, a chronic cough) the cause is more likely than not a dust mite allergy. It's been 100 years since scientists first began to discover the link between dust mites and allergic disease, and yet it is still a widespread problem few people seem to know about. The good news is that it very practical to get rid of them. The purpose of this guide is to help you get dust mites out of your home, and make it healthier and more comfortable for you, your family, and your friends. This guide is broken into four chapters:
Chapter I: Understanding Dust Mites
Chapter II: How Dust Mites Affect Your Health
Chapter III: Stopping Dust Mites
Chapter IV: Removing Allergens From Your Home
By following the steps in this guide, you can dramatically reduce the amount of dust mite allergen in your home. If you are an allergy sufferer, this will likely greatly improve your quality of life. If you have children, it will make them less likely to become sensitized to dust mites and far less vulnerable to allergic diseases that affect hundreds of millions of people like hay fever, eczema, and asthma. And your home will be healthier and more comfortable for friends and family who suffer from dust mite allergies.Dust mites are tiny creatures that are found in most homes. In fact, 84% of homes in the US have detectable dust mite allergens[1]. They are 0.2mm-0.3mm long(or around 1/100 of an inch). This makes them just a little too small to be seen by our eyes. They are so small and so numerous in some households that a single gram of dust could contain a few hundred mites.
[1] Source: 84% of American homes have dust mite allergensDust mites are in your home because you are their food source. Although they can eat other things, like fungus, their primary food is human skin flakes. Humans naturally shed their skin. Estimates of how much skin a person sheds daily vary, but it's enough to make up a large portion of house dust. The skin flakes float around indoors and settle on surfaces. Porous surfaces like fabrics can retain a large amount of these flakes that becomes lodged or stuck within them. They also rub off into our bed when we sleep or into clothes, towels, and furniture during the day.
Even with regular cleaning, our skin accumulates at high concentrations in our mattresses and bedding, curtains, rugs, fabric covered chairs and sofas, and other objects like clothing, boxes and books. This is the food supply for dust mites, and as they eat, they leave behind fecal pods, which contain several different allergens. This is undetectable by our vision and smell, since the pods are too small to see and odorless. But what has happened is that our home and the items in the home that were full of harmless skin flakes in the form of house dust have become full of allergens. These allergens have a half-life upwards of 10 years, so they just sit in your house until you remove them.
Because dust mites rely on humid air, climate determines where they are found. In arid regions like deserts, they may not be present. In temperate climates, humidity may be hospitable for dust mites only in some parts of the year. They survive these seasonal droughts by staying in different parts of their life cycle. Dust mites start out as eggs that hatch into larva, which grow into protonymphs then tritonymphs then adults. In their protonymph form, they can survive several months of dryness. So for example in a climate with dry winters and warm, humid summers, the adult dust mite population may recede in winter, and grow throughout the summer as they lay new eggs to continue the cycle.
The health impact of dust mites is staggering. 84% of US households have dustmites allergens. 20 million people in the United States are affected by a dust mite allergy. Worldwide, hundreds of millions of people are affected. Exposure to dust mite allergens is:
Dust mites produce dozens of different allergens, some of which are more associated with asthma, and others with eczema. They are primarily "aeroallergens", which means that exposure mainly comes from breathing them in. Exposure to the allergens over time can cause people to develop a dust mite allergy, which is also called becoming "sensitized".
Allergic rhinitis(AR), also called hay fever, refers to sneezing, running nose, watery or swollen eyes. It is the most common symptom of dust mite allergy, and dust mite allergy is one of the most common causes. Allergic rhinitis is known to have an impact on sleep quality and mental health. This large cohort study found that worse AR is associated with anxiety and depression [3]. Another study found that allergy suffers scored significantly higher on 6 scores of mental health [4].
[3] Severity of allergic rhinitis impacts sleep and anxiety
[4] Psychological aspects of female patients with moderate-to-severe persistent allergic rhinitis
Asthma is a chronic disease of the lungs, with symptoms like coughing, shortness of breath, chest tightness. Asthma itself is a clinical diagnosis which takes in to account things like history of symptoms and whether or not they get worse at different times of the day. If you have a persistent cough you suspect is related to allergies, you could think of it as an asthma-like symptom without worrying about whether you meet diagnostic criteria for asthma.
Dust mites are a major cause of asthma. In fact, if you have a dust mite allergy, you are several times more likely to develop asthma.
This study concluded that dust mite allergy is associated more with cough type asthma than with wheezing type asthma, and that the dust mite asthma was both more severe and harder to control than the non-dust mite asthma [4].
This excellent paper makes a foundational argument for dust mites being the main cause of asthma [5].
[4] Association between house dust mites sensitization and level of asthma control and severity
[5] Pro: The Evidence for a Causal Role of Dust Mites in Asthma
Eczema, also called atopic dermatitis, is a skin condition characterized by dry, itchy skin and red rashes. There is evidence that eczema is caused by inhalation of dust mite allergens. One study had participants with eczema inhale dust mite allergens. Nine out of twenty participants had worsened or new skin symptoms in the hours following exposure [5]. Another study found an association between severity of eczema and level of allergens found in patients' homes [6].
[5] Induction of skin reactions by inhalation
Everyone who has children should remove dust mite allergens from their home, even if they don't have a dust mite allergy because exposure to dust mite allergens produce a risk that children will develop one. This large birth cohort study showed that higher levels of dust mite allergen in the household leads to a higher chance of developing an allergy for children. In the study, 26.5% of participants developed an allergic response to dust mite allergens, and those children were at significantly higher risk of asthma [7]. It's also worth noting that is the parent experiences hay fever(allergic rhinitis) this advice is even more important, since that is associated with higher rates of sensitization in their children.
Despite this being such a serious and widespread health issue, there seems to be a low general awareness of dust mites. This is kind of sad, but the good news is that this problem is easily fixable, and is a huge opportunity for us to make the world better for all the people we love.
There is a powerful strategy to stop dust mite activity in your home: controlling the humidity. This approach is easy and cheaply attainable through the use of dehumidifiers. Many other sources may discuss washing with hot water, freezing, or the use of acaricides(poisons for mites) to control mites, however humidity is a far better tool since it is so simple to setup, and will prevent mites from surviving in your space with basically no drawbacks. There is also a great study that backs up this approach, it showed that by keeping the humidity under 50%, and only using normal household cleaning procedures, mite allergens were reduced by 90% over a 17 month period[8] .
I recommend aiming for 40% relative humidity in your house. There a few reasons for this recommendation:
A great first step is to know what the humidity around you is doing. For this, you will need a hygrometer, which is a device that measures relative humidity. They are cheap, and I'd recommend buying a handful of them and putting them around your house, and also one outside in a convenient place you will see daily. (these are the ones I use: Amazon link). Different parts of your home may behave differently. For example, an upstairs story could vary by 5-10% from downstairs. Also, the humidity outdoors can vary widely, which could impact the indoor humidity. Having some sensors around are a good way to make sure your dehumidifier setup is working, and also to develop an understanding about how humidity behaves in your house.
To keep the humidity low, you will need a dehumidifier. They are relatively cheap and simple devices. Important factors to consider when buying a dehumidifier:
For larger spaces, or for more humid climates you may need more than one dehumidifier. I'd recommend getting one(or more) to start, and then watching how they affect your space. Pay attention to how fast you are able to drop the humidity, how much of a difference there is with outside humidity, and what the lowest level you can bring it to is. If you want to be able to drop the humidity faster, or get it lower, keep adding humidifiers until you feel confident in your ability to maintain your chosen humidity level.
If you want to go deeper, you can consult a guide such as this one from consumer reports: Dehumidifier Buying Guide
Once you start having lower humidity in your house, you should begin to notice a difference in air quality within a few weeks. It's important to maintain low humidity constantly. Dust mites can survive by "drinking" from the air if the humidity is quite high for only one hour out of the day. Dust mite protonymphs can survive 4-11 months of drought, but the overall dust mite populations will be much lower if you have sustained low humidity for the entire year.
Now that you have started a plan that will stop dust mites from adding new allergens to your home, the next step is to remove all the allergens they have made over the years from your home. Humans shed something like a pound of skin every year, so it's possible that there could be pounds of disease-causing allergens in your home.
Bedding is the number one place where mites live and allergens build up. The second worst items are fabric curtains, and the third worst is carpet. Fabric objects that are in the open like upholstered furniture, towels, and rugs are likely resevoirs of allergens. Books, boxes, and bags used for storage as well as clothes are other likely places. A key point to remember here is that some items are worse than others.
If you are a dust mite sensitized person, you may be able to discern how much allergen an item contains simply by being around it. For example, I have asthma-like dust mite symptoms, and being next to contaminated items for only a few minutes will cause me to begin coughing. Also, you can "sniff" an item and if you are allergic and the item is contaminated you should quite clearly feel an effect, although please be careful and don't do this if you are having symptoms. Cleaning your home may happen gradually as you clean one small place at a time. Early on, if you can full clean a room, it can be a good opportunity to try and feel the difference between being in the clean room and being in dirty ones. Getting in touch with your senses is a really powerful skill and very helpful through the cleaning process.
Your bedroom is a great place to start decontamination, since it has the highest concentrations of allergens, and you spend a lot of time there. I highly recommend getting an allergy cover for your mattress and pillows. This creates a barrier existing allergens, and can save you from needing to buy an expensive replacement mattress. The second good habit is to wash your bedding and pillowcases biweekly.
After fixing up your bedding area, I'd recommend trying to get rid of the worst items. Fabric curtains, rugs, and upholstered furniture. The worst items can have far worse allergenic effects, and if they are in an open space you will be breathing them in quite often. Getting rid of fabric stuff feels difficult, but actually quite often you can find replacements from a material that won't hold allergens and dust. Keep pushing and you'll be surprised! If you are having a hard time convincing yourself whether it's possible to do in your entire house, just try to find one room you can completely clean of suspect items. Then spend time there and see if it feels better!
A good method for cleaning a space full of items like a closet is to take all of the items out of the space. Then vacuum, mop, and wipe down the interior surface of the space. Then clean all of the items and do a smell test on each one before putting it back in. This is a good opportunity to get rid of items that may be particularly dirty but of low value like cardboard boxes or fabric bags holding items. Also, as a bonus you have a great opportunity to reorganize the items in the space! Also, while cleaning an area, I recommend using a portable air filtering device to help keep allergens out of the air while you clean.
For washable items like clothes, studies show that washing with detergent will remove around 80% of allergens. Adding bleach can increase the amount removed in a single wash, but it will not work for colored fabrics and may irritate the skin, so I recommend doing multiple washes instead. Washing at 40C is much more effective than at 30C for removing allergens [9]. Some fabrics retain allergens more than others. If you can do a smell test on clothes, I recommend continuing to wash the ones that still seem contaminated. Sometimes they can get better after 2 or 3 washes.
[9] Optimal conditions for the removal of house dust mite[...]using mechanical laundryThank you for reading this guide! Dealing with a whole house issue can be daunting and overwhelming, but I hope you stick with it - it's worth it. Dust mites are having a huge negative impact on our health, and by removing them from your home, you are helping move everyone into a healthier future. Also, tell your friends about what you learned! Hundreds of millions of people(and maybe more) have an opportunity to vastly improve their health, if they can only know what to do.