What are the other Names of this Condition? (Also known as/Synonyms)

• Bed Mite Allergy
• HDM Allergy
• House Dust Mite Allergy

What is Dust Mite Allergy? (Definition/Background Information)

• Dust Mite Allergy is a common condition that manifests as an abnormal immune reaction/response, frequently due to inhaled dust mite wastes present in home and some office environments. In warm-humid indoor spaces, dust mites may be present all-round the year
• House dust mites (HDMs) are short-lived, but ubiquitous microscopic creatures, about 0.2-0.3 mm in size, that feed on dead cell matter shed by humans and pets. They also thrive in spaces abundant in mold (a type of fungus). A house may typically contain millions of dust mites, and they may be found in the bedding, carpets, upholstered furniture, curtains, and even on stuffed toys
• HDMs are not pathogenic and do not infect humans or pets. However, they produce fecal matter and female mites lay numerous eggs, towards the end of its life cycle. These along with dead mite exoskeleton form fine allergenic material in the form of dust (dust mite wastes)
• The respiratory system is typically affected, since wastes from dust mites are inhaled/breathed in. The signs and symptoms of the allergic reaction may include runny nose, sneezing, and breathing difficulties. In some cases, Dust Mite Allergy may lead to an anaphylactic shock, which is a medical emergency
• Chronic exposure to house dust mites can result in asthma and sinus infection. Dust Mite Allergies are generally diagnosed by conducting a physical examination, assessing the symptoms, and via an antibody blood test or a skin-prick test
• Anti-allergic medications form the first line of treatment for mild Dust Mite Allergies. However, in the case of a severe allergic reaction (anaphylaxis), epinephrine or adrenaline injections are recommended
• The prognosis of Dust Mite Allergy is generally good with adequate treatment, although the condition can recur. Awareness of such allergies and taking steps to eliminate dust mites (to the extent possible) from indoor spaces is the best form of prevention

Who gets Dust Mite Allergy? (Age and Sex Distribution)

• Dust Mite Allergies can occur in both children and adults. Individuals of any age may be affected
• No gender preference is noted and both males and females are affected
• All racial and ethnic groups are equally vulnerable to the condition

What are the Risk Factors for Dust Mite Allergy? (Predisposing Factors)

The risk factors for Dust Mite Allergy include:

• Regular exposure to fecal wastes of dust mites, to dead dust mites
• Humid and poorly-ventilated indoor spaces
• Family history of an associated allergy (including asthma and hay fever)
• Infants and young growing children are more at risk
• Having one form of allergy puts one at risk for other forms too

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Dust Mite Allergy? (Etiology)

An allergic reaction occurs in an individual with Dust Mite Allergy, because the immune system recognizes the house dust mite wastes (that contain specific enzymes) as being dangerous and harmful to the body.

• The dust mites are mostly present in beds and mattresses, upholstered furniture, sofas, carpets, wall hangings and curtains, including stuffed toys; they can invisibly float around and be carried like dust when disturbed (while walking, running on carpets, dusting furniture, jumping on beds, etc.)
• Exposure to dust mites result in the production of antibodies, specifically immunoglobulin E (IgE). After developing these antibodies, every  time the individual is exposed to the allergen(s), the antibodies that are circulating in blood causes an antibody-antigen reaction
• This results in the production of histamine and other chemical messengers, which cause the symptoms seen during an allergic reaction
• The extent of exposure that triggers an allergy may not be significantly large. Sometimes, mild or minor contact with the allergen is sufficient to trigger Dust Mite Allergy

In some cases, a severe allergic reaction termed as anaphylaxis may occur, which is a medical emergency that requires immediate medical attention.

What are the Signs and Symptoms of Dust Mite Allergy?

The signs and symptoms of Dust Mite Allergy may start to appear within a few minutes, to a couple of hours, after the individual has been exposed to dust mite waste matter. Depending on the level of sensitivity and quantum of exposure, the symptoms may be mild or severe. A severe allergic reaction is a medical emergency.

The signs and symptoms of Dust Mite Allergy may include:

• Sneezing is the most common symptom noted
• Coughing, chest tightness
• Runny or stuffy nose
• Watery eyes, redness, and irritation; conjunctivitis-like symptoms including swollen, red eyes
• Irritation of the throat
• Shortness of breath (trouble breathing), wheezing
• Asthma-like symptoms; in children (mainly) with asthma or other lung conditions, Dust Mite Allergy can make it worse
• Face pain due to sinus involvement
• Skin can be itchy
• Sleeping difficulties
• Severe infestation can cause severe respiratory symptoms including allergic rhinitis, asthma, and atopic dermatitis (a skin condition)

Generally, not all episodes of allergy will be of the same severity. In some individuals, the most severe symptom caused by Dust Mite Allergy is anaphylaxis.

• Anaphylaxis (sometimes called an anaphylactic shock) is a life-threatening, whole-body allergic reaction
• During anaphylaxis, tissues in various body parts release histamine and other messenger chemicals, which causes swelling of the throat and other symptoms
• Swelling of the throat is especially dangerous as this can cause shortness of breath. If the swelling is not reduced soon, then there is a possibility that the individual could die from a lack of sufficient oxygen
• It can also result in a bluish skin, weak pulse, and decreased blood pressure (hypotension)

How is Dust Mite Allergy Diagnosed?

The diagnosis of Dust Mite Allergy may involve the following:

• Physical examination, assessment of symptoms, and medical history evaluation (history of allergies in the family)
• Radioallergosorbent (RAS) test; to determine the specific allergy-causing substance
• Skin-prick (allergy) test:
  • For this test, tiny amounts of certain substances are injected right underneath the skin , or scratched into the superficial skin of the forearm, upper arm, or back
  • After 15-20 minutes, if the spot where the chemical was injected swells, or if there is redness noticed, then this indicates that the individual may be allergic to the substance
• Blood test to detect antibodies (IgE antibody test)

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Dust Mite Allergy?

The complication of Dust Mite Allergy is associated with the allergic reaction itself and it depends on the severity of the reaction. It may include:

• Anaphylactic shock/reaction that may be life-threatening
• Severe asthma attacks
• Development of chronic conditions including asthma and sinusitis, when the lungs are affected due to continued exposure
• Aggravation of symptoms in those with underlying lung conditions/infections
• Having one form of allergy can make the individual prone to other allergy types
• In severe reactions, a tracheostomy may have to be performed during an emergency situation 

How is Dust Mite Allergy Treated?

The treatment of Dust Mite Allergy may be undertaken in the following manner:

• To the extent possible, limit or reduce exposure to house dust mites
• Anti-allergic medication for mild reactions; antihistamine therapy, that is prescribed by the allergy physician
• Use of leukotriene modifiers (allergy medication)
• Symptomatic treatment; use of nasal decongestants, including steroid sprays
• In the case of anaphylaxis (severe allergic reaction), epinephrine or adrenaline is immediately administered
• Breathing support  including oxygen as necessary, control asthma symptoms and low blood pressure
• Bronchodilators for respiratory conditions such as asthma, wheezing, etc.
• Undertake appropriate treatment for any underlying lung infections or illnesses
• Immunotherapy (allergy shots), in case of severe allergies, for long-term tolerance development

How can Dust Mite Allergy be Prevented?

Currently, it may not be possible to prevent Dust Mite Allergy. It is also difficult to fully eliminate house dust mites from houses or indoor spaces, but the level of infestation may be minimized by considering the following steps:

• Keep houses clean and clean regularly
• Use suitable dust masks while cleaning, else the symptoms may get worse
• Change bedsheets, pillow covers, curtain cloths periodically
• Washing clothes can kill dust mites (use hot water when possible); heat dry in washing machine
• Sun dry bedding, blankets, and cushions, when possible
• Use dust mite proof covers on mattresses and pillows, cushions. Use anti-mite fabrics when infestation is heavy
• Avoid carpeted floors, where possible use alternatives such as wood, ceramic, or vinyl
• Wash hands thoroughly with soap and water, in case of contact with an allergen, especially before eating
• Reduce exposure to dust mites: Avoid indoor wetness, keep spaces dry and well-ventilated
• Use exhaust fans and dehumidifiers: Keep room at low humidity (less than 45%) and room temp at or over 22 deg. C
• Do not keep windows and ventilators shut during all times of the day
• Clean indoor spaces regularly for dust and dust mite wastes; use high-power vacuum cleaners on room carpets, mattresses, and sofas. However, even though this may not be very effective, it may remove dead cell matter from homes (that is food for the house mites)
• Use high-quality air-conditioning filters (such as HEPA filters) and furnace filters

Additionally, the following may be considered:

• Studies have shown that breastfeeding children for 4-6 months or over, can help build their body immunity and make them less prone to allergies
• Appropriate maternal diet during pregnancy can help build stronger resistance (against allergies) in children
• Generating public awareness on various allergies

In case the child or adult is susceptible to an anaphylactic shock (high-risk individuals) from Dust Mite Allergy, the following should be considered:

• Being watchful of triggers and avoid them
• Wearing medical alert information bracelets
• Carry auto-injector epinephrine or adrenaline medications such as EpiPen, Anapen, or Twinject. Since the condition may recur, it is advised to carry 2 doses (2 pens)
• Supervise children on how to self-administer the injection, if required
• If child is prone to anaphylactic reaction, then information (preferably written instructions) should be given to day care, school authorities accordingly
• Adults should inform their spouses, colleagues, and friends, about the condition, in case of a future emergency

What is the Prognosis of Dust Mite Allergy? (Outcomes/Resolutions)

• The prognosis of Dust Mite Allergy depends on the severity of the signs and symptoms, but it is generally good with appropriate treatment
• However, the condition can recur if the buildup of house dust mites in indoor spaces is not minimized. Also, chronic and regular exposure to HDM can result in severe lung infections and worsening of asthmatic symptoms, especially in children
• In some cases, the allergic reaction may be severe, causing anaphylaxis. This is a medical emergency that can lead to a respiratory failure. It requires an immediate treatment of the condition. In such cases, the prognosis is guarded and it depends on whether immediate medical assistance is provided

Additional and Relevant Useful Information for Dust Mite Allergy:

Sneezing due to house dust is common, but it need not lead to an allergic condition in all cases.