Dust mite allergy

Definition

 Dust mite allergy is an allergic reaction to tiny bugs that commonly live in house dust. Signs of dust mite allergy include sneezing and runny nose. Many people with dust mite allergy also experience signs of asthma, such as wheezing and difficulty breathing.

 Dust mites, close relatives of ticks and spiders, are too small to see without a microscope. Dust mites eat skin cells shed by people, and they thrive in warm, humid environments. In most homes, bedding, upholstered furniture and carpeting provide an ideal environment for dust mites.

 Steps to reduce the number of dust mites in your home can often control dust mite allergy. Medications or other treatments may be necessary to relieve symptoms and manage asthma.

Symptoms

 Dust mite allergy symptoms caused by inflammation of nasal passages include:

• Sneezing
• Runny nose
• Itchy, red or watery eyes
• Nasal congestion
• Itchy nose, roof of mouth or throat
• Postnasal drip
• Cough
• Facial pressure and pain
• Swollen, blue-colored skin under your eyes
• In a child, frequent upward rubbing of the nose

 If your dust mite allergy contributes to asthma, you may also experience:

• Difficulty breathing
• Chest tightness or pain
• An audible whistling or wheezing sound when exhaling
• Trouble sleeping caused by shortness of breath, coughing or wheezing
• Bouts of coughing or wheezing that are worsened by a respiratory virus such as a cold or the flu

Causes        

Dust mites eat skin cells people have shed, and rather than drinking water, they absorb water from humidity in the atmosphere. They thrive in temperatures between 18.5 and 29 C and a relative humidity higher than 50 percent.

 House dust is easily trapped in the fibers of bed linens, furniture cushions and carpeting. These materials also hold moisture well. Consequently, bedrooms are ideal habitats for dust mites.

 Dust also contains the feces and decaying bodies of dust mites, and it's the proteins present in this dust mite "debris" that are the culprit in dust mite allergy.

What causes the allergic reaction

Allergies occur when your immune system reacts to a foreign substance such as pollen, pet dander or dust mites.

 Your immune system produces proteins known as antibodies. Some of these antibodies protect you from unwanted invaders that could make you sick or cause an infection. When you have allergies, your immune system makes antibodies that identify your particular allergen as something harmful, even though it isn't. When you inhale the allergen or come into contact with it, your immune system responds and produces an inflammatory response in your nasal passages or lungs. Prolonged or regular exposure to the allergen can cause the ongoing (chronic) inflammation associated with asthma.

Tests and diagnosis

 Your doctor may suspect dust mite allergy based on symptoms, an examination of your nose, and your answers to his or her questions.

 He or she may use a lighted instrument to look at the condition of the lining of your nose. If you have an allergy to something airborne, the lining of the nasal passage will be swollen and may appear pale or bluish.

 Your doctor may suspect a dust mite allergy, based on your comments. For example, if your symptoms are worse when you go to bed or while cleaning — when dust mite allergens would be temporarily airborne — you may have dust mite allergy.

 If you have a pet — another common source of allergies — it may be more difficult to determine the cause of the allergy, particularly if your pet sleeps in your bedroom. The source of your allergy may be clearer after you take steps to reduce levels of the possible allergens from your home.

Treatments and drugs

 The first treatment for controlling dust mite allergy is avoiding dust mites as much as possible. When you minimize your exposure to dust mites, you should expect fewer allergic reactions or the reactions should be less severe. However, it's impossible to completely eliminate dust mites from your environment. You may also need medications to control symptoms.

Allergy medications

Your doctor may direct you to take one of the following medications to improve nasal allergy symptoms:

Antihistamines reduce the production of an immune system chemical that is active in an allergic reaction. These drugs relieve itching, sneezing and runny nose. Over-the-counter antihistamine tablets, such as fexofenadine (Allegra Allergy), loratadine (Alavert, Claritin), cetirizine (Zyrtec Allergy) and others, as well as antihistamine syrups for children, are available. Prescription antihistamines taken as a nasal spray include azelastine (Astelin, Astepro) and olopatadine (Patanase).

Corticosteroids delivered as a nasal spray can reduce inflammation and control symptoms of hay fever. These drugs include fluticasone propionate (Flonase), mometasone furoate (Nasonex), triamcinolone (Nasacort AQ), ciclesonide (Omnaris) and others. Nasal corticosteroids provide a low dose of the drug and have a much lower risk of side effects compared with oral corticosteroids.

Decongestants can help shrink swollen tissues in your nasal passages and make it easier to breathe through your nose. Some over-the-counter allergy tablets combine an antihistamine with a decongestant. Oral decongestants can increase blood pressure and shouldn't be taken if you have severe high blood pressure, glaucoma or cardiovascular disease. In men with an enlarged prostate, the drug can worsen the condition. Talk to your doctor about whether you can safely take a decongestant.

 Over-the-counter decongestants taken as a nasal spray may briefly reduce allergy symptoms. If you use a decongestant spray for more than three days in a row, it can actually make nasal congestion worse.

Cromolyn sodium prevents the release of an immune system chemical and may reduce symptoms. You need to use this over-the-counter nasal spray several times a day, and it's most effective when used before signs and symptoms develop. Cromolyn sodium doesn't have serious side effects.

Leukotriene modifiers block the action of certain immune system chemicals. Your doctor may prescribe this prescription tablet, montelukast (Singulair). Possible side effects of montelukast include upper respiratory infection, headache and fever. Less common side effects include behavior or mood changes, such as anxiousness or depression.

Lifestyle and home remedies

 Avoiding exposure to dust mites is the best strategy for controlling dust mite allergy. While you can't completely eliminate dust mites from your home, you can significantly reduce their number. Use these suggestions:

Use allergen-proof bed covers. Cover your mattress and pillows in dustproof or allergen-blocking covers. These covers, made of tightly woven fabric, prevent dust mites from colonizing or escaping from the mattress or pillows. Encase box springs in allergen-proof covers.

Wash bedding weekly. Wash all sheets, blankets, pillowcases and bedcovers in hot water that is at least 54.4 C to kill dust mites and remove allergens. If bedding can't be washed hot, put the items in the dryer for at least 15 minutes at a temperature above 54.4 C to kill the mites. Then wash and dry the bedding to remove allergens. Freezing nonwashable items for 24 hours also can kill dust mites, but this won't remove the allergens.

Keep humidity low. Maintain a relative humidity below 50 percent in your home. A dehumidifier or air conditioner can help keep humidity low, and a hygrometer (available at hardware stores) can measure humidity levels.

Choose bedding wisely. Avoid bedcovers that trap dust easily and are difficult to clean frequently.

Buy washable stuffed toys. Wash them often in hot water and dry thoroughly. Also, keep stuffed toys off beds.

Remove dust. Use a damp or oiled mop or rag rather than dry materials to clean up dust. This prevents dust from becoming airborne and resettling.

Vacuum regularly. Vacuuming carpeting and upholstered furniture removes surface dust — but vacuuming isn't effective at removing most dust mites and dust mite allergens. Use a vacuum cleaner with a double-layered microfilter bag or a high-efficiency particulate air (HEPA) filter to help decrease house-dust emissions from the cleaner. If your allergies are severe, leave the area being vacuumed while someone else does the work. Stay out of the vacuumed room for about two hours after vacuuming.

Cut clutter. If it collects dust, it also collects dust mites. Remove knickknacks, tabletop ornaments, books, magazines and newspapers from your bedroom.

Remove carpeting and other dust mite habitats. Carpeting provides a comfortable habitat for dust mites. This is especially true if carpeting is over concrete, which holds moisture easily and provides a humid environment for mites. If possible, replace wall-to-wall bedroom carpeting with tile, wood, linoleum or vinyl flooring. Consider replacing other dust-collecting furnishings in bedrooms, such upholstered furniture, nonwashable curtains and horizontal blinds.

Install a high efficiency media filter in your furnace and air conditioning unit. Look for a filter with a Minimum Efficiency Reporting Value (MERV) of 11 or 12 and leave the fan on to create a whole house air filter. Be sure to change the filter every three months.

Source: http://www.mayoclinic.com/health/dust-mites/DS00842/METHOD=print