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What are Allergies? Causes and Treatment of Allergy

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Definition of Allergies

Allergies are unusual reactions to simple nontoxic substances. The substances that cause allergy are known as allergens, may be inhaled with breath, swallowed, or exposed to the skin.

The most common allergens that cause troubles are: pollens, mold spores, house dust mites, food stuffs, insect stings or bite, some species of plants, insect spores, latex rubber, odor, viruses, bacteria, medications and atmospheric conditions (like too hot or cold). Allergic reactions can occur in more than one area, such as sneezing along with the skin rashes and may include more than one symptom.

Normally, the body has its own system which enables it to learn and defend itself through encountering, and remembering enemies one by one. For decades, medical science has taken advantage of this ability by using vaccination to create immunity, the immunologic memory of a disease. Allergic reactions happen when immune system incorrectly recognizes harmless foreign particles as potentially harmful.

Causes of Allergy

The root cause of allergy is still unknown. The condition has a tendency to penetrate in families. An allergic individual is expected to have relatives who are allergic than would be on the basis of chance, but factors other than hereditary, also play a specific role.

Evidence of this fact is, infants who are breast-fed have lesser chances to develop allergies than bottle-fed babies. It is still a mystery, why an individual becomes sensitive to some substances and not to others?

Types of Allergy

Individuals can be affected by so many kinds of allergic diseases. The most common allergic diseases are allergic rhinitis, non-allergic rhinitis, asthma, allergic dermatitis, contact dermatitis and urticaria.

Allergic rhinitis is a common term used to apply to any allergy-based symptoms. It can be a seasonal disease (also known as “hay fever” or “pollen allergy”) or a year-round problem. Hay fever or seasonal allergic rhinitis occurs due to the allergy to pollens of trees, grasses, weeds or mold spores because it is also the season of pollination.

Perennial allergic rhinitis is caused by house dust, animals’ dander, mold and some foods.
Asthma is caused by intrinsic and extrinsic (inhaled) factors. Intrinsic factors are pollens, dust, dust mites, animal fur, animal dander or feathers. Extrinsic factors are respiratory infections like a cough, cold or bronchitis, smoking or other air pollutants, and can also be caused by an allergy to a specific food or medication.

Eczema is an allergic dermatitis or a topic dermatitis which can be caused by foods or other allergens.

Contact dermatitis occurs due to exposure to certain plants such as poisonous ivy or poisonous oak, cosmetics, medications, some metals and chemicals.

Urticaria, also called “hives”, happen because of allergy to foods, such as nuts, tomatoes, shellfish and berries. Aspirin and penicillin can also give birth to hives.

Systemic inflammatory response to Allergens


The characteristic behavior known as nasal salute, also known as allergy salute, is the habit of wiping of the nose in upward direction because of itching.


Eyes redness and itching caused, due to allergic conjunctivitis.

Air passage:

Bronchial constriction, wheezing and dyspnoea, sometimes complete attacks of asthma.


Feeling of fullness or closeness, pain, and hearing loss due to the lack of eustachian tube drainage.


Skin allergy includes various rashes, such as eczema, hives (urticaria) and contact dermatitis.


It is not common; headache has been reported in some cases with environmental or chemical allergies.

Systemic allergic reaction is also called anaphylaxis. It depends on the rate of severity. It can cause cutaneous reactions, bronchial constriction, edema, hypotension, coma and even death. Hay fever is one common example of a very minor allergy that affects large number of people.

Treatment of Allergies

There are very limited conventional medical treatments for allergies. Perhaps the most important factor in therapy is the removal of allergens from the environment, and avoiding environments in which contact with allergens is possible.


• Wear a pollen mask when mowing the grass or during house cleaning.

• Stay indoors in the morning time and on windy days, as the pollens are at their higher count.

• Read and understand food labels especially those who have food allergies

• Keep windows and doors shut during the peak pollination seasons.

• Use air conditioner in the house and car.

• Divest the home of indoor plants and other sources of mold.

• Keep away dander-producing animals from the house.

• Replace feather pillows, woolen blankets and clothing with cotton or synthetic materials.

• Enclose mattress, box springs and pillows in plastic barrier cloth.

• Wash bed sheets, mattress pad and blankets fortnightly in hot water at 45C.

• Remove carpets and upholstered furniture (drastic measure).

• Use acaricide, it kills house-dust mites or a tannic acid solution that neutralizes the allergen in mite droppings.

• Use a dehumidifier.


After avoidance or control if allergy persists, medications would be necessary. Most common medications for allergy are:

Decongestants: These administered through spray or oral route to open nasal passages. Examples of spray decongestants are oxymetazoline and phenylephrine. Oral decongestants include pseudoephedrine and combinations of air passage decongestants and analgesics.

Steroid nasal sprays: It also available in form of spray to inhibit the inflammatory response. Medications include fluticonase, mometasone, triamcinolone, and beclomethasone.

Antihistamines: These drugs inhibit the action of histamine which is responsible for allergic symptoms. Short acting antihistamines are time tested and over-the-counter which relieve allergy with mild to moderate symptoms, but also cause sedation. In case of children, pediatrician must be consulted before using such kind of medicines, as they may affect learning. One previously prescribed drug, loratadine (also in chewable form), is now available over the counter.

It does not cause drowsiness or affect learning in children. Long-acting antihistamines cause a lesser amount of drowsiness, are equally effective and generally do not hinder learning. The medications, which need a prescription after diagnose, are fexofenadine, and cetirizine. Other nonprescription antihistamines include diphenhydramine, chlorpheniramine maleate and clemastine.


When all efforts including, avoidance, environmental control measures and medications fail to control allergy, the specialist may propose allergy immunotherapy. Immunotherapy involves the course of injections of allergen extracts to “desensitize” the patient.

The treatment starts with injections of allergen’s solution administered one to five times a week, with the gradual increase in strength. When the peak level of dose is obtained, maintenance injections are given at growing intervals until patient starts to receive injections only once a month.

It could take up to six months or more to show results. Usually it takes about three to four years for the patient to be asymptomatic.

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