Rajan is a botany and chemistry major. He has worked as a poultry breeder for 23 years, breeding layer and broiler parents.
What Is Allergy
In simple terms, allergy is an increased reaction to an external harmless substance, also called an allergen, that causes the body's immune or defence system to react strongly to it.
This reaction is seen in some individuals who are then said to be allergic to that particular substance or allergen. The majority that does not exhibit any reaction to that very substance is said to be non-allergic to it.
Allergy is not a disease but a condition whose reactions can be from mild to life-threatening.
Some common factors have been noted between allergies and allergens. They are:
- The immune system is always involved and is a must factor.
- The allergens cause allergic reactions that might be instant or delayed.
- Prevention is at least as important as treatment.
Why Are Incidences Of Allergy Rising?
Worldwide, incidences of allergy are increasing. Initially, the rise was in the UK, USA and Europe but with increasing industrialization, it has spread to the developing countries as well.
Also, starting with respiratory allergies like hay fever and asthma, now we see a jump in food allergies as well. The factors responsible for this change and all allergies, in general, are believed to be :
- Our increased dependence and consumption of refined and processed foods rather than vegetables and fruits which was the norm decades ago.
- Increased use of certain nuts like peanuts in some communities.
- Decreasing levels of Vitamin D which is very necessary for proper immune system development - firstly because of the changed food habits and secondly, due to lower sunshine exposure by way of staying indoors more and increased use of sunscreens today.
- Increased use of skin creams with ingredients coming from certain nuts that are allergenic though the evidence for allergy through the use of cosmetics is limited.
- A very strong reason is our reduced exposure to environmental bacteria and microorganisms due to our use of sanitizers and cleaners which kill these bacteria and consequently reduce our immunity and increase our susceptibility.
- Hereditary factors where increasing incidences are seen in families and their offsprings in succeeding generations due to vertical transmission.
How Mast Cells Act Under Attack By An Allergen
What Happens During An Allergic Reaction?
Harmless substances do not cause any reaction in most people. However, some people are sensitive to these very substances which though harmless cause allergic reactions in those sensitive to them.
As the body perceives these allergens to be harmful and a threat, the immune system reacts by producing special antibodies to counter this allergen. These antibodies are Immunoglobin E (IgE) and are allergen-specific. The allergen attaches itself to the IgE and also to the mast cells and basophils which are the body's soldier cells.
The mast cells are present in tissues that come into contact with the external environment like the nose, mouth, eyes, skin, throat and the gut.
The first attack produces no symptoms only the production of the IgE. The next encounter is identified by the mast cells and they then start producing histamines, a chemical which is meant to fight the allergen. It is this histamine that produces the characteristic inflammatory, allergic symptoms like itching, watery eyes, runny nose, sore throat, cough, shortness of breath, wheezing and tightness of chest etc.
Types Of Allergies
Allergies can be broadly classified into 2 categories :
- Food Allergy - Includes all that is consumed or eaten.
- Environmental Allergy - Includes various external triggers like dust, mites, weather changes, pollution, smoke, grasses, pollen etc.
In this hub, I will deal with ways to tackle and reduce the severity of allergy due to pollen.
About Pollen Allergy / Seasonal Allergies / Hay Fever
Pollen allergy symptoms occur from the months of March to September depending on the individual's sensitivity to the type of pollen. Pollen from different plants is in highest concentrations at different times during these months.
- Pine pollen is more during March & April.
- Grass pollen during May, June & July.
- Weed pollen from August to September.
The severest allergic symptoms are encountered with the grass and weed pollen generally.
Pollen contains the male reproductive cell of the plants. Since pollen has to be dispersed by air in a major way, they are very light and produced in huge numbers so that some reach the female flowers and attach to the stigma, which contains the female reproductive cell. This is necessary to propagate the plant species and is nature's way to keep the plant generation running.
However, this becomes a bane for those who are allergic to pollen.
Pollen allergy is also called allergic rhinitis and hay fever.
The symptoms include sneezing, runny nose, watery eyes, headache, sore throat, cough, sleep difficulties and difficulty in breathing.
Repeated attacks can lead to it getting chronic and manifest as asthma.
How Are Allergies Treated Medically?
The normal practice is to prescribe antihistamines which are medicines that counter the allergic symptoms caused by the release of the chemical histamine. Side effects of these medicines include drowsiness.
Some antihistamines like fexofenadine do not cause drowsiness, though.