Mite Allergy

Mite allergy is a common allergic reaction caused by tiny bugs that live in household dust. These microscopic creatures thrive in warm, humid places like bedding and furniture, and their droppings can trigger symptoms ranging from sneezing and runny nose to more serious breathing problems.

Table of contents

• What is mite allergy?
• Understanding dust mites
• Symptoms
• Who is affected?
• Diagnosis
• Treatment options
• Prevention and reducing exposure

What is mite allergy?

Mite allergy, also known as house dust allergy or dust mite allergy, is an allergic reaction (your body’s response to a substance it mistakenly views as harmful) to tiny bugs that live in house dust^[1]. When you have this allergy, your immune system (your body’s defense system against infections) reacts to proteins found in dust mites, particularly those in their droppings and dead bodies^[2].

The allergy develops when dust mite proteins enter your body. The first time you encounter these proteins, your body creates immunoglobulin E (IgE), which are antibodies your immune system makes to attack what it sees as invaders. When you encounter dust mite proteins again, your immune system has a stronger response, causing allergy symptoms^[2].

Understanding dust mites

Dust mites are tiny, eight-legged relatives of spiders^[2]. They are so small that you cannot see them with your eyes alone—they measure only about one-quarter to one-third of a millimeter^[15]. Under a microscope, they look like tiny white bugs^[15].

These creatures live in household dust and feed on dead skin cells that people and pets naturally shed^[2]. The main component of household dust is shed skin flakes, which is the mite’s preferred food source^[4]. Unlike fleas or other bugs, dust mites do not bite people^[4].

Dust mites prefer warm, humid environments. They thrive in places where the temperature ranges between 20 to 30 degrees Celsius and humidity exceeds 60 percent^[25]. In most homes, dust mites are found in bedding, mattresses, upholstered furniture, carpets, curtains, and soft toys^[2][4].

The gut of the dust mite contains powerful digestive enzymes that remain in their fecal matter. These enzymes, particularly one called peptidase 1, are the major cause of allergic reactions^[5]. A dust mite produces around 20 fecal pellets per day^[5].

dust mite allergy, house dust allergy

Symptoms

Symptoms of mite allergy are similar to those of hay fever^[1]. Common symptoms include^[1][2]:

• Sneezing
• Runny nose
• Stuffy or congested nose
• Itchy, red, or watery eyes
• Itchy nose, roof of mouth, or throat
• Coughing
• Postnasal drip (mucus that drips down the back of your throat)
• Facial pressure and pain
• Swollen, discolored skin under the eyes

Many people with dust mite allergy also experience symptoms of asthma^[1]. These symptoms may include^[1][2]:

• Trouble breathing
• Chest tightness or pain
• Wheezing (breathing difficulty with a whistling or gasping sound)
• Trouble sleeping caused by shortness of breath, coughing, or wheezing
• Coughing or wheezing that gets worse with a cold or flu

A mite allergy can range from mild to severe. A mild case may cause a runny nose, watery eyes, and sneezing. Sometimes the condition may be ongoing, called chronic^[1]. Symptoms are likely to be worse while sleeping or cleaning, when dust mite allergens are more likely to be in the air^[1].

Dust mites can also trigger skin conditions. Some people have an itchy red skin condition called eczema that can flare up when exposed to dust mites^[15]. Severe dust mite infestation in the home has been linked to atopic dermatitis^[9].

Who is affected?

Anyone can develop a mite allergy^[2]. Dust mite allergies are common—approximately 20 million people in the United States have this allergy^[2]. Globally, house dust mite allergy affects an estimated 65 to 130 million people^[25].

You are more likely to develop a dust mite allergy if you have asthma, eczema, hay fever (also called allergic rhinitis), or a biological family history of atopy (a genetic likelihood to develop allergies)^[2].

Dust mite allergy typically develops in childhood or adolescence, with most symptoms appearing before age 20^[5].

Diagnosis

If you have dust mite allergy symptoms, it’s a good idea to see your healthcare provider. They may refer you to an allergist, a healthcare provider who specializes in allergies^[2].

A healthcare professional might suspect you have a dust mite allergy based on your symptoms and your answers to questions about your home^[10]. To confirm the diagnosis, they might use a tool with a light to look at the lining of your nose. If you have an allergy to something in the air, the lining of the nose might be swollen and appear discolored^[10].

Your healthcare provider may use different tests to help diagnose a dust mite allergy. Before conducting tests, they may ask you questions including^[2]:

• Do you have a family history of dust mite allergies?
• Have you ever been diagnosed with other allergies before?
• What are your symptoms?
• Do you take any medications to treat your symptoms?
• Do you spend a lot of time in dusty areas?
• How often do you vacuum your carpets, wash your bedding, and clean other surface areas?

Tests used to diagnose a dust mite allergy include^[10]:

Allergy skin test: This test looks for certain allergens. An allergist might do the test by scratching tiny amounts of allergens, including dust mites, onto the skin of your forearm or upper back. A health care provider checks the skin for signs of allergic reactions after 15 minutes. An allergic reaction is a red, itchy bump where the allergen was put on the skin. The most common side effects are itching and redness, which usually go away within 30 minutes^[10].

Allergy blood test: Some people cannot have a skin test because they have a skin issue or take a medicine that can affect the results. Instead, they might have a blood test that screens for allergens, including dust mites^[10].

Treatment options

Treatment for mite allergy focuses on controlling symptoms and reducing exposure to dust mites. However, it’s not possible to get rid of all dust mites from the home^[10].

Medicines

Several types of medicines can help improve symptoms^[10]:

Antihistamines: These medicines relieve itching, sneezing, and runny nose. Antihistamine tablets you can get without a prescription include fexofenadine (Allegra Allergy), loratadine (Alavert, Claritin), and cetirizine (Zyrtec Allergy). There are also antihistamine syrups for children^[10].

Decongestants: These medications help clear the nasal passages and sinuses. They work by shrinking the blood vessels in the nose, which reduces swelling and congestion^[15].

Corticosteroids: Steroids are a type of medication used to help reduce inflammation. They can be prescribed orally, inhaled, or applied to the skin^[15].

Nasal irrigation: This is the process of flushing out your nasal passages with a salt water solution. It can help clear mucus and reduce allergens^[15].

Immunotherapy

Immunotherapy is a treatment that works by exposing you to small amounts of allergen, which helps the body build up immunity and reduce allergy symptoms over time^[15].

Subcutaneous immunotherapy (also called allergy shots) has been used for decades to treat dust mite allergy. This involves weekly shots for approximately six to eight months, then monthly shots for approximately three to five years. The shots must be given in a doctor’s office where a physician is present because of the risk of allergic reactions^[13].

Sublingual immunotherapy (SLIT) is a newer treatment option. It is a daily medication placed under the tongue that can be taken at home. One such treatment, approved in 2017, trains the immune system to no longer recognize dust mites as an allergen. Because there is a risk of an allergic reaction, you must carry an EpiPen at all times and know how to recognize and treat severe allergic reactions^[13][14].

Recent studies have shown that sublingual immunotherapy for dust mites is safe and effective. After one year, patients who received this treatment had fewer nose and eye symptoms and used fewer medications to control allergy symptoms compared to those who did not receive the treatment^[13].

Prevention and reducing exposure

The first treatment for controlling dust mite allergy is avoiding dust mites as much as possible. Being around dust mites less can lead to fewer or less severe allergic reactions^[10].

While it’s impossible to completely eliminate dust mites from your home, there are many actions you can take to reduce their numbers^[15]:

Bedding

Since we spend roughly one-third of our day in bed, bedding is one of the most important areas to address^[25]:

• Put special dust-proof covers on pillows, mattresses, and box springs^[7]
• Wash all bedding (including sheets, pillowcases, and blankets) in hot water at least 130 degrees Fahrenheit, as cold water will not kill the dust mites^[7]
• Avoid bedding stuffed with foam rubber or kapok^[26]
• Use pillows made of synthetic fiber rather than foam, feather, or down^[7]

Floor coverings and furniture

• If possible, remove wall-to-wall carpeting—wood, tile, or vinyl flooring without a rug is best^[7]
• If you must keep rugs or carpeting, vacuum frequently (at least twice a week)^[7]
• Clean floors with a damp rag or mop rather than dry-dusting or sweeping^[26]
• Avoid upholstered furniture when possible^[4]

Indoor climate control

• Use a dehumidifier or air conditioner to lower humidity to below 50 percent^[15]
• Keep your home well aired^[4]
• Change air filters on the furnace every month^[7]

Other household items

• Limit stuffed animals kept in bedrooms or put them in plastic containers^[26]
• Wash stuffed animals about once a month or put them in a hot dryer for 20 minutes^[7]
• Keep your kitchen clean and avoid leaving food out^[26]

The period from May to August is known as the “mite season,” when dust mites actively breed due to increased humidity levels and rising temperatures. During these warm months, it’s especially important to maintain good ventilation and lower humidity in your home^[25].