Allergies - Who, Why, What & When
Pollen allergy, commonly called hay fever, is one of the most common chronic diseases. Worldwide, airborne allergens cause the most problems for people with allergies. The respiratory symptoms of asthma, which affect approximately one in twelve people, are often provoked by airborne allergens.
Although the number of people suffering with an allergy has increased in the last few decades, there is more education and a greater understanding of the immense impact that allergies have on our lives, from allergy symptoms to causes to treatments.
There is no clear explanation for the increase in allergies; however there are two main theories. The first theory is that awareness and diagnosis have improved in recent years and the second is that the increase in general air pollution and indoor air pollution have made allergens more common.
An allergy is characterised by an overreaction of the human immune system to a foreign protein substance (“allergen”) that is eaten, breathed into the lungs, injected or touched and which otherwise does not bother most people.
This immune overreaction can results in symptoms such as coughing, sneezing, itchy eyes, runny nose and scratchy throat. In severe cases it can also result in rashes, hives, lower blood pressure, difficulty breathing, asthma attacks, and even death.
People who have allergies often are sensitive to more than one substance. Types of natural allergens that cause allergic reactions include:
Allergy is not necessarily the same as sensitivity or intolerance to a substance. This is particularly so in the area of food where, for example, lactose intolerance is not classed as a food allergy because the symptoms do not arise from the immune system.
Scientists think that some people inherit a tendency to be allergic from one or both parents. This means they are more likely to have allergies. They probably, however, do not inherit a tendency to be allergic to any specific allergen. Children are more likely to develop allergies if one or both parents have allergies. In addition, exposure to allergens at times when the body’s defences are lowered or weakened, such as after a viral infection or during pregnancy, seems to contribute to developing allergies.
Each IgE antibody is specific to one particular substance. In the case of pollen allergy, each antibody is specific for one type of pollen.
IgE is special because it is the only type of antibody that attaches tightly to the body’s mast cells, which are tissue cells, and to basophils, which are blood cells. When the allergen next encounters its specific IgE, it attaches to the antibody like a key fitting into a lock. This action signals the cell to which the IgE is attached to release powerful chemicals, including histamine, which cause the symptoms of allergy.
The symptoms of airborne allergies are familiar to most people:
In people who are not allergic, the mucus in the nasal passages simply moves foreign particles to the throat, where they are swallowed or coughed out. But something different happens in a person who is sensitive to an airborne allergen.
In sensitive people, as soon as the allergen lands on the lining inside the nose, a chain reaction occurs that leads the mast cells in these tissues to release powerful chemicals, including histamine. These powerful chemicals contract certain cells that line some small blood vessels in the nose, causing fluids to escape and the nasal passages to swell—resulting in nasal congestion. Histamine can also cause sneezing, itching, irritation, and excess mucus production, which can result in allergic rhinitis.
The shortness of breath is due to a narrowing of the airways in the lungs and to excess mucus production and inflammation. Asthma can be disabling and potentially fatal.
Genetics: The risk of having an allergy amongst the general population is around 10-20%. However, If one parent is allergic, a child’s risk rises to 50% and if both parents are allergic, to 75%.
Age, sex, and siblings: On average, children are more likely to suffer from allergy than adults (children can sometimes ‘grow out of’ allergic disease) and the onset can occur at any age. More boys than girls have atopic asthma and hay fever, although this difference reduces in adult life. Children from large families and those with older siblings are less likely to develop allergies, probably because they are more exposed to childhood infection, which makes the developing immune system less likely to over-react to an allergen.
Early-life, or extreme/sudden, allergen exposure: It has been suggested that exposure to allergens like cigarette smoke, traffic pollution, dust, pollen, mould and pet dander in early life may increase a child's risk of developing an allergy. For example breast feeding for six months or more has been shown to decrease the risk of asthma and other allergies in babies. Premature babies are also more at risk of developing allergies than full-term babies.
The most common allergic diseases
Asthma is a disease of the lungs that causes airways to become blocked or narrowed making it difficult for you to breathe. It harder to breathe in than breathe out. Asthma attacks are caused by triggers which are either allergens (like house dust mite, mould, pet dander) or irritants like cigarette smoke, traffic pollution or cold air.
Asthma attacks are usually temporary, but if an asthma episode is severe, a person may need emergency treatment to restore normal breathing. Despite the far reaching effects of asthma, much remains to be understood as to what causes it and how to prevent it.
Asthma is potentially the most serious of the allergic diseases. In the UK, for example, during 2008-9, there were nearly 80,000 hospital admissions for asthma of which nearly half were of children aged 14 and under.
Although asthma can cause severe health problems, in most cases prevention and treatment can control it and allow a person to live a normal and active life.
Hay fever (seasonal rhinitis) is characterised by itchy nose and eyes, sneezing and runny nose. In the UK it is mainly caused by exposure to grass pollen (perennial rye and timothy grass).
Perennial rhinitis persists all year round. Sometimes people with perennial rhinitis do experience worse symptoms in the pollen season. Around 50% of those with perennial rhinitis have an allergy while the rest have some other problem with their nose or sinuses.
The most common airborne allergens
The ‘Allergy Season’
If you are allergic to pollen, you will need to be aware of seasonal variations. Other allergens like house dust mite, traffic and other indoor pollution, tend to be present year-round.
The pollen season varies for different plants and, in the UK, it lasts from early Spring to late Autumn.
Then along came Airora 4-in-1 ...
The levels of allergens and lung irritants are much higher in your home than outside. Traditional air purifiers can do little to help because of their limited ability to clear the air, and keep the air clear, of all of the types of allergen and pollution which might cause you problems. Only Airora 4-in-1 treats ALL types of pollution, in a WHOLE ROOM, in seconds (no filter required!).
Understanding Indoor Air Quality
In the open air, 'Hydroxyl Radical Cascades' are continuously created by the complex chemical interactions that occur naturally in the atmosphere. Hydroxyls are the powerful but entirely safe and natural air cleaning agent, often referred to by scientists as 'Natures Detergent', which continuously decontaminate the air and gives 'fresh air' that clean and refreshing feel that we all love.
Indoors, the natural atmospheric ingredients that continuously create hydroxyl radicals don't exist and allergens remaining active, smells remain smelly and bacteria and viruses constantly build up in the air and on surfaces. Consequently, indoor air is generally much more polluted than outdoor air, yet until recently it has received far less public attention.
We often spend up to 90% of our time indoors (at home, work or at school), so exposure to indoor air pollution is potentially much more damaging to our health. That is why the World Health Organisation considers indoor air pollution as one of the main health threats today, and states that around 3% of the global burden of disease is directly attributable to it.
Indoor air pollution
Indoor air pollution is a complex mixture of microbes and substances in the air that are potentially harmful to health. The composition of this indoor air pollution can vary greatly depending, for example, where you live and on the contents of your home.
In a home in a non-urban setting for example, house dust mite, pollen and mould spores can be a major cause of indoor air pollution and related health problems. In a new-build home or office, fumes from paints and insulation, new carpet and furniture can significantly contribute to the pollution. Especially in industrial or built up areas, traffic and industry pollution also play an increasing part in indoor air pollution.
In our homes the build up of both bacteria and viruses in the air is much greater than outside.
Sources of pollution
Damp dusting, not just dry dusting, is needed to reliably remove dust rather than just spreading it around. Most carpets are a major reservoir for dust and for every six rooms in a house around 40 pounds of dust is generated in a single year, much of which is human skin as we regularly shed our outer layer of skin as part of a continuous renewal process.
The main components of dust which can affect your health indoors are:
Prevention of indoor air pollution
It is always better to try to prevent indoor air pollution occurring before attempting to reduce or remove it:
Where the main source of pollution is internal rather than external, it is helpful to open windows after bathing, showering or cooking so that damp and mould don't build up.
An effective air purifier can play an essential part in reducing indoor air pollution in your home or place of work. But the key word here is ‘effective’ and the unfortunate truth is that most traditional air purifiers are not very effective!
Various types of traditional air purifier focus on different pollutants, typically pollens, spores and other particles or on gaseous pollutants. Some combine technologies to address more than one type of pollutant.
But all have the same drawback, they only clean the air passing through the device and rely, to only limited effect, on a high throughput of air to draw in pollution from the ever changing air in the room. However good the filter mechanism, they will only ever clean a modest proportion of pollutants from the air in a room because constant air changes, re-contamination, re-circulation and eddy formation means that there are always significant airborne pollutants in a room which have not been drawn into the device.
Then along came Airora ...
There is now however a new generation of air purifiers of which the Airora 4-in-1 is the first (and currently only) one. These air purifiers use the naturally occurring ‘hydroxyl radical cascade’ process found in the outside atmosphere to clean internal air (and exposed surfaces) of the full range of pollutants; allergens and irritants, pollutant gasses, bacteria and viruses and smells.
House Dust Mites
House dust mites are one of the most potent and common domestic and workplace triggers of allergic reactions.
Dust mites are microscopic eight-legged creatures called arachnids and they are closely related to the spider and the tick. They are found in every home and their presence is not an indication of poor cleaning!
It is not the dust mite itself which is the allergen but enzymes (proteins) found in its droppings and decaying body. The whole droppings themselves are particles between 4 and 20 microns in size but may crumble into particles as small as 0.5 microns across.
House dust mites feed upon the skin scales naturally shed by humans and other animals which are found in house dust. Although their presence is harmful to people who become allergic to them, dust mites do not bite or spread diseases.
While usual household insecticides have no effect on dust mites, fortunately there are multiple ways to reduce exposure to dust mite allergens in your home.
Dust mite allergy
As with other allergens, dust mite allergens cause an ‘over-reaction’ of the immune system in an allergic person. In allergy sufferers Immunoglobulin E (IgE) antibodies present on the surface of mast cells trigger the release of histamine when allergens stick to these IgE antibodies. It is histamine that produces the characteristic symptoms of an allergic reaction.
Dust mites love homes
Dust mites love humidity
To survive, house dust mites absorb water from the air. When humidity is less than 50% they tend to dry out and die. They also prefer temperatures around 21°C (70°F).
It is thus crucial to get rid of damp in your home. Ventilate by opening windows, and check for condensation in the kitchen and bathrooms. If you live in a humid area, consider buying a dehumidifier but remember that very dry air can be uncomfortable especially if you suffer with sinus or respiratory conditions.
Getting rid of dust mites in your home
The fight is never ending - dust mites are everywhere and even if you can get rid of all of them in your home, new ones would still appear (they are carried into your home on people’s clothing, for instance). So, look for long-term solutions which will reduce your house dust mite burden.
These measures will create an environment that could seriously reduce the house dust mite burden in your home.
Anti-mite spray and powder
Regular use of an anti-mite dust spray or powder can be of help. An anti-mite spray can penetrate mite reservoirs in carpets, soft furnishings and mattresses and anti-mite dry powder carpet cleaner can help get rid of mites where they nest.
When choosing allergy cleaning products, be careful to use cleaning products with natural ingredients. Spraying a chemical, especially on a regular basis, can be a severe trigger for people suffering with allergies.
Dust mites are not the only allergen in house dust
Cockroaches are commonly found in crowded cities and in, for example, the southern United States. Certain proteins in cockroach feces and saliva also can be found in house dust. These proteins can cause allergic reactions or trigger asthma symptoms in some people, especially children. Cockroach allergens likely play a significant role in causing asthma in many inner-city populations.
Can an air cleaner help?
While numerous manufacturers of ‘air cleaners’ / ‘air filters’ claim to be able to clear dust mite allergens from the air, they can only reduce, not eliminate, the problem, because:
You can learn more about why traditional air cleaners don’t work well here and why Airora’s unique technology does work here.
Rhinitis, including hay fever, is the most common of all the allergic diseases. The typical symptoms such as blocked nose, watery eyes, & running nose may persist all year round (perennial rhinitis) or may be seasonal. Even though it’s often undiagnosed and its symptoms often thought of as harmless, the impact perennial rhinitis can have on a person’s overall quality of life can be significant.
What is rhinitis?
Rhinitis is inflammation of the nose. It may, or may not, be caused by an allergy.
Another symptom of perennial allergic rhinitis is post-nasal drip, where mucous runs down the back of the nose and then into the throat and the airways, producing a persistent phlegm cough.
Causes of allergic rhinitis
Allergic rhinitis is caused by exposure to an airborne allergen. Common allergens include:
What happens when the allergen is breathed in
In allergic rhinitis, blood flow is increased, the mucous membranes swell and there is increased mucous production, all occurring in response to histamine production on exposure to the allergen. The result is nasal congestion, nasal blockage, and/or a runny nose.
Allergic rhinitis diagnosis
A simple description of your symptoms and their seasonality may be all that is required to diagnose rhinitis.
If confirmation and/or identification of an allergic cause is needed, then a skin prick test can be used. A tiny drop of allergen extract is placed on the skin at either the arm or the back. If you are allergic to the substance, a small red weal will appear within a short period.
Allergic rhinitis can be reduced by avoiding exposure to allergic triggers, for example:
House dust mite
Medical treatments for allergic rhinitis
If your symptoms are mild, you can use a long-acting non-sedating antihistamine such as Claritin (loratadine), NeoClaritin (desloratadine), Zyrtec (cetirizine), Xyzal (levocetirizine) or Allegra (fexofenadine). These are available without a prescription, but you should always consult your pharmacist before use.
The older antihistamines like chlorpheniramine (Piriton) and hydroxyzine (Atarax) have a significant sedating effect and should not be used if you are driving, operating machinery, or studying. These older drugs also interact with alcohol so having even a small amount to drink may significantly affect performance.
If rhinitis mainly affects your eyes, antihistamine eye drops, such as Otrivine (antazoline) may help.
In addition to an antihistamine, a nasal decongestant (drops or a spray) may also be helpful in clearing a blocked nose. Some of these decongestants are corticosteroids, which act by reducing inflammation including Beconase (beclomethasone) and Flixonase (fluticasone). Non-corticosteroid nasal decongestants include Otrivine/Sudafed (xylometazoline). All of these can be bought without a prescription. However, only use a decongestant for as short a time as possible, as the nose tends to stop responding to these medications over time.
In general, antihistamines and topical nasal steroids are most effective against seasonal allergic rhinitis/hay fever but may still help with perennial allergic rhinitis.
Can an air cleaner help?
While numerous manufacturers of ‘air cleaners’ / ‘air filters’ claim to be able to clear those allergens leading to rhinitis from the air, they can only reduce, not eliminate, the problem, because:
Dr Wyatt blogs on his lifetime's experience of Indoor Air Quality Issues.