Introduction
Of the many components in house dust to which people may be allergic, the most important is the house dust mite.
House dust mites are microscopic, insect-like creatures related to the tick and spider family. They feed primarily on scales from human skin and are found in most areas commonly inhabited by people.
This reference summary will give you an overview of allergy and allergic reaction to house dust mites.
Allergies
The body’s immune system is equipped to fight substances that can harm the body, such as viruses or bacteria.
Some substances that enter the body are harmless, so the body ignores them.
Allergens are harmless substances, but they can cause allergic reactions in some people.
Pollen, house dust mites, mold and animal dander are examples of allergens.
In an allergic person, the body mistakes the allergen for harmful substances. This causes the cells to release substances, such as histamine. The release of histamine and other chemicals causes the body to experience an allergic reaction.
An allergic reaction may cause a runny nose, itching, swelling or asthma.
The reason that some people have allergies is not entirely clear. The potential to develop allergies is thought to be hereditary.
Avoiding allergies
The best way to prevent an allergic reaction is to avoid the substance that you're allergic to, although this isn't always easy or practical.
Below is some practical advice that should help you avoid the most common allergens.
Allergy clinic
You should be referred to a specialist allergy clinic for tests to find out what caused the anaphylaxis. Knowing what allergen triggered the allergic reaction can help you avoid further episodes of anaphylaxis.
Some of the tests commonly used to determine allergies include:
- a skin prick test – your skin is pricked with a tiny amount of a suspected allergen to see if it reacts by becoming red, raised and itchy
- a blood test – a sample of your blood is taken to test its reaction to a suspected allergen
What causes allergies?
- Allergies occur when the body's immune system reacts to a particular substance as though it's harmful.
- It's not clear why this happens, but most people affected have a family history of allergies or have closely related conditions such as asthma or eczema.
- The number of people with allergies is increasing every year. The reasons for this are not understood, but one of the main theories is it's the result of living in a cleaner, germ-free environment, which reduces the number of germs our immune system has to deal with.
- It's thought this may cause it to overreact when it comes into contact with harmless substances.
Allergies to House Dust mites
Both decomposing animal parts and the protein that surrounds mite fecal pellets causes’ mite allergy.
In homes, high levels of mites can be found in mattresses, pillows, bed linens, carpets, draperies, upholstered furniture and stuffed toys.
Mites reproduce very rapidly. Anew generation is produced about every 3 weeks. Therefore, it is easy to see why dust mites may cause a significant problem for the allergic person.
Walking, vacuuming, cleaning or changing bed lines easily stirs up dust mite allergens.
These particles may remain suspended in the air for about 20 to 30 minutes after being disturbed.
When these allergens are inhaled, sensitized patients may develop allergic symptoms such as nasal congestion or asthma.
Mites depend on atmospheric moisture and human dander for survival.
Locations that are both dry and cool have very few house dust mites.
Recommended Steps to Control House Dust Mites
Taking steps to control your indoor environment will help reduce allergen exposure and may help reduce allergy symptoms.
The highest levels of might allergen in the home are found in the bedroom and especially in the bed.
Therefore, reducing allergen exposure in the bedroom is an important first step.
- Encase the mattress and box springs in an allergen-impermeable cover.
- Allergen-impermeable materials are made of plastic or specialized materials that are tightly woven and prevent allergens from being inhaled.
- They can also be used to cover wool blankets and down comforters.
- Encase pillows in allergen-impermeable covers or replace with washable synthetic pillows.
- Wash the bed sheets, mattress pad, blankets and bedspread WEEKLY in hot water. Water at a temperature of 130 degrees or higher is required for killing house dust mites.
Although washing in hot water kills house dust mites, the bedding will soon become re-infested with mites. Therefore, regular washing is necessary. If you cannot wash everything in hot water, weekly washing in warm water will temporarily wash out the allergen.
- Replace bulky, upholstered Furniture in the bedroom and other rooms in the house. If possible, convert to vinyl, leather or wooden furnishings.
- Keep easily cleaned surfaces uncluttered in the bedroom. Small objects should be placed in drawers or closed cabinets to avoid dust collection.
- Eliminate draperies and other dust collecting material, such as books, from the bedroom. Cloths should be kept in drawers or in the closet with the doors shut.
- Cover hot air vents with filters to help clean the air at its point of entry or close off registers in the bedroom and use an electric radiator.
- Limit the number of stuffed toys in the bedroom and wash them weekly in hot water.
- Remove thick carpeting from the bedroom and other rooms in the house. Carpeting placed over concrete floors, such as in basements is not recommended because it traps moisture and promotes mite and mold growth. Hardwood or linoleum floors are preferable for patients with allergies.
- Another way to decrease the population of house dust mites is to reduce indoor humidity to less than 50 percent and to maintain room temperature at 70 degrees or less.
- Avoid sleeping or lying on upholstered furniture.
- Carpets should be vacuumed regularly. Using double thickness vacuum cleaner bags or small-pore vacuum filters can significantly reduce the amount of airborne dust mite allergen. Sensitive patients may find it helpful to wear a mask while vacuuming to reduce the amount of allergen inhaled.
- Vacuuming removes mite allergen from carpets but removes few live mites. Chemical agents are available for killing mites and denaturing the antigen. However, the effects are not dramatic and are not maintained for long periods. Therefore, use of these agents in the homes of house dust mite-sensitive people is not recommended routinely.
Medication
A variety of medications are available to treat allergy symptoms caused by house dust mites.
The most effective treatment for house dust mite allergy is AVOIDANCE though medication of the home environment.
If mite modification of the home environment dose not completely controls your symptoms, your physician can discuss the possibility of changing medical therapy or starting immunotherapy (allergy shots).
Pets
It's not the pet fur that causes an allergic reaction. Instead, its flakes of their dead skin, saliva and dried urine.
If you can't permanently remove a pet from the house, you could try:
- keeping pets outside as much as possible, or limiting them to a particular area of the house, preferably an area without carpet
- not allowing pets in bedrooms
- washing pets at least once a week
- regularly grooming pets outside
- regularly washing all bedding and soft furnishings on which a pet has lain
- using an air filter in rooms where you spend most of your time
- increase ventilation with fans, air-conditioning or by opening windows
If you're visiting a friend or relative with a pet, ask them not to dust or vacuum on the day you're visiting, as this will stir up the allergens into the air. Taking an antihistamine medicine about an hour before entering a pet-inhabited house can also help reduce your symptoms.
Mould spores
Tiny particles released by moulds can cause an allergic reaction in some people.
You can help prevent this by:
- keeping your home dry and well-ventilated
- removing any indoor pot plants from your home
- not drying clothes indoors, store clothes in damp cupboards or packing clothes too tightly in wardrobes
- dealing with any damp and condensation in your home
- avoiding damp buildings, damp woods and rotten leaves, cut grass and compost heaps
Food allergies
By law, food manufacturers must clearly label any foods that contain something that's known to cause allergic reactions in some people. By carefully checking the label for the list of ingredients, you should be able to avoid an allergic reaction.
People with food allergies most often experience an allergic reaction while eating out at a restaurant. You can avoid this by:
- not relying on the menu description alone (remember, many sauces or dressings could contain allergens)
- communicating clearly with the waiting staff and asking for their advice
- avoiding places where there's a chance that different types of food could come into contact with each other, such as buffets or bakeries
- let restaurant staff you know your dietary requirements, including how severe your food allergy or intolerance is
- always check what allergens are in the dish even if you have eaten it before, as recipes and ingredients can change
Remember, simple dishes are less likely to contain "hidden" ingredients. If you're not sure
Hay fever
Pollen allergies – more commonly known as hay fever – are caused when trees and grasses release pollen into the air. Doctors often call hay fever allergic rhinitis.
Different plants pollinate at different times of the year, so the months that you get hay fever will depend on what sort of pollen(s) you are allergic to. Typically, people are affected during spring (trees) and summer (grasses).
To help keep your hay fever under control, you can:
- check weather reports for the pollen count and stay indoors when it's high, if possible
- avoid drying clothes and bedding outside when the pollen count is high
- wear wraparound sunglasses to protect your eyes
- keep doors and windows shut when possible
- shower and change your clothes after being outside
- avoid grassy areas, such as parks and fields – particularly in the early morning, evening or night, when the pollen count is highest
- if you have a lawn, try asking someone else to cut the grass for you
Insect bites and stings
If you've ever suffered a bad reaction to an insect bite or sting, it's important to take precautions to minimise your risk.
When you're outdoors, particularly in the summer, you could:
- cover exposed skin
- wear shoes
- apply insect repellent
- avoid wearing strong perfumes or fragrances, as these can attract insects
SUMMARY
Dust mites are found in homes, especially in areas that are warm and humid. For people with dust mite allergy, the best treatment is medication of the home environment and especially in the bedroom. By developing a better understanding of house dust mite allergy and how to control it, you will be better able to manage your allergies and will benefit by needing less medication.
