Allergies are a major causes of illness around the world. When you have allergies, it means your immune system reacts to something that’s usually harmless to most people.


Allergies are one of the most common chronic diseases. A chronic disease is a disease that lasts a long time or occurs often. An allergy occurs when the body’s immune system sees a foreign substance- such as pollen, bee venom or pet dander--- as harmful and overreacts to it. The substances that cause allergic reactions are called allergens. When someone has allergies, their immune system makes an antibody called immunoglobulin E(IgE). These antibodies respond to allergens. The symptoms that result are an allergic reaction.

The severity of allergies varies from person to person and can range from minor irritation to an anaphylaxis reaction-- a potentially life-threatening emergency. While most allergies can’t be cured, treatments can help relieve your allergy symptoms.


Who at risk for allergies and why?


Allergies can develop at any age, but most food allergies begin at a young age, and many are outgrown. Environmental allergies can develop at any time. The initial exposure or sensitization period may even begin before birth. Individuals can also outgrow allergies over time. It is not fully understood why one person develops allergies and another does not, but there are several risk factors for allergic conditions. Family history, or genetics, plays a large role, with a higher risk for allergies if parents or siblings have allergies. There are many other risk factors for developing allergic conditions. Children born via cesarean section have a higher risk of allergy as compared to children who are delivered vaginally. Exposure to tobacco smoke and air pollution increases the risk of allergy. Boys are more likely to be allergic than girls. Allergies are more common in westernized countries, and less common in those with a farming lifestyle. Exposures to antigens, use of antibiotics, and numerous other factors, some of which are yet unknown, also contribute to the development of allergies. This complicated process continues to be an area of medical research.


Types of allergies

The parts of the body that are prone to allergic symptoms include the eyes, nose, lungs, skin, and gastrointestinal tract. Although the various allergic diseases may appear different, they all result from an exaggerated immune response to foreign substances in sensitive individuals.

Food allergy:

A food allergy occurs when the body’s immune system sees a certain food as harmful and reacts by causing allergic symptoms. There are different types of allergic reactions to foods.

IgE- mediated allergies- the antibodies react with certain foods and cause symptoms. The most common food allergy are depicted in the image below.

Non-IgE mediated allergies and food intolerance- other parts of the body’s immune system react to a certain food. This reaction causes symptoms, but does not involve an IgE antibody. Someone can have both IgE mediated and non-IgE mediated food allergies.

Not all people who react to a certain food have an allergy. They may have a food intolerance. Examples are lactose intolerance, gluten intolerance or sulfite sensitivity. Food intolerance does not involve the immune system.

Dust allergy

Dust is easily found everywhere, outside or inside of households. It can increase or decrease with seasons, can adhere to different surfaces and originate from different places or things.

People with dust allergies often suffer the most inside their own homes or in other people’s homes. Oddly enough, their symptoms often worsen during or immediately after vacuuming, sweeping and dusting. The process of cleaning can stir up dust particles, making them easier to inhale.

Common dust triggers are dust mites, cockroaches, mold, pollen and pet hair, fur or features.

Insect allergy

Warm weather does signal the arrival of some unwanted visitors like stinging and biting insects such as Bees, Wasps, Hornets, Yellow jackets and Fire ants. They are the most common stinging insects that cause and allergic reaction.

Non-stinging insects can also cause allergic reactions. The most common are cockroaches and the insect-like dust mite. Allergies to these two insects may be the most common cause of year-round allergy and asthma.

Biting insects such as mosquitoes, kissing bugs, bedbugs, fleas and certain flies are the most common biting insects known to cause an allergic reaction. Rarely, insect bites may trigger a life-threatening allergic reaction.

A bite from a Lone star tick can cause people to develop an allergy to meat.

Non-stinging and non-biting insects can also cause allergic reactions, particularly cockroach, a dust mite is too small to see with the naked eye. The cockroach and dust mite’s waste and body cause allergic reactions. They also can trigger asthma symptoms and asthma attacks.

Pet allergy

Allergies to pets with fur are common, especially among people who have other allergies or asthma. Cat allergies are about twice as common as dog allergies.

It is important to know that an allergy-free(hypoallergenic) breed of dog or cat does not exist.

People with pet allergies can react to harmless proteins in the pet’s urine, saliva or dander(dead skin cells). pet allergens can collect on walls, furniture, clothing and other surfaces.

Pet hair is not an allergen but I can collect the allergens mentioned above and also can carry other allergens like dust and pollen.

Drug allergy

True allergies to drugs(medicines) occur in only a small number of people. Most drug reactions are not allergic, but are side effects of the properties of the medicine, hence the correct term to be used is “adverse reactions to drugs.”

A diagnosis of the cause of the drug reaction is usually based only upon the patient’s history and symptoms. Sometimes skin testing for drug allergy is also done.

In many cases, patients may have a reaction while taking several drugs at the same time. In these instances, unless the allergist-the doctor specialized in allergies-can identify an allergy to one of the drugs, there is no way to tell which drug is responsible. The doctor might recommend then to stop the suspicious drug(s).

There are two broad categories of adverse reactions to drugs:

- true allergic reactions involving the immune system and IgE

- non-allergic reactions

Latex allergy

A latex allergy is an allergic reaction to natural rubber products . Natural rubber products can be found in everyday products such as: gloves, rubber bands, balloons, bandages, condoms and diaphragms, and other natural rubber products containing latex.

Contact with these products can cause an allergic reaction. Some people have allergic reactions by breathing in latex fibers in the air. Some people have allergic reactions from skin contact with latex.

Exposure to synthetic latex does not cause the symptoms of latex allergy.

An allergy to latex can be a serious health risk.

Mold allergy

If you have an allergy that occurs over several seasons, you may be allergic to the spores of molds or other fungi. Molds live everywhere and upsetting a mold sources can send the spores into the air.

Mold and mildew are fungi. Since fungi grow in so many places, both indoors and outdoors, allergic reactions can occur year round.

Mold and mildew are different from plants or animals in how they reproduce and grow. Their seeds called spores, travel through the air. Some spores spread in dry, windy weather and others in foggy or when humidity is high.

Although there are many types of molds, only a few dozen cause allergic reactions. Most outdoor molds become inactive during the winter. Indoors, fungi grow in damp areas such as the bathroom, kitchen or the basement.

Pollen allergy

Pollen is one of the most common triggers of seasonal allergies. Many people know pollen allergy as “hay fever.” Experts usually refer to pollen allergy as “seasonal allergic rhinitis”

Each spring, summer and fall, plants release tiny pollen grains. Most of the pollen that cause allergic reactions come from trees, weeds and grasses.

Grasses are the most common cause of allergy. Ragweed is a main cause of weed allergies. Other common sources of weed pollen include sagebrush, pigweed, lamb’s quarters and tumbleweed. Trees like birch, cedar and oak also produce highly allergenic pollen.

Cockroach allergy

Cockroaches can be an allergy trigger as well. The saliva, feces and shedding body parts of cockroaches can trigger both asthma and allergies. These allergens act like dust mites, aggravating symptoms when they are kicked up in the air.

Symptoms of allergy

The symptoms that result from your body’s immune system to some substances-allergens- are called allergic reaction. Allergens can get into your body in many ways to cause an allergic reaction.

.they can be inhaled into your nose and your lungs

.they can be ingested by mouth

.they can be injected

.they absorbed by the skin

They severity of symptoms during an allergic reaction can vary widely. Some symptoms include:

. Itchy,watery eyes

. Itchy, runny nose

. Sneezing

. Rashes

. Hives

. Stomach cramps

. Vomiting

. Diarrhea

. Bloating

. Swelling

. Redness

. Pain

. Tongue swelling

. Face swelling

. Cough

. Throat closing

. Wheezing

. Chest tightness and losing breath

. Feeling faint, light-headed



Some of these symptoms can be a sign of a life-threatening allergic reaction.


Allergic rhinitis

Allergic rhinitis(hay fever) is the most common of the allergic diseases and refers to nasal symptoms that are due to aeroallergens. Year-round, or perennial, allergic rhinitis is usually caused by indoor allergens, such as dust mites, animal dander, or molds. Seasonal allergic rhinitis is typically caused by tree, grass, or weed pollens. Many individuals have a combination of both seasonal and perennial allergies. Symptoms result from the inflammation of the tissues that line the inside of the nose after exposure to allergens. The eyes, ears, sinuses, and throat can also be involved. The most common symptoms include the following:

. Runny nose

. Stuffy nose

. Sneezing

. Itchy nose, eyes, ears, and throat

. Postnasal drip(throat clearing)

Eye allergy

Allergic eyes(conjunctivitis) are inflammation of the tissue layers(membranes) that cover the surface of the eyeball and the under-surface of the eyelid. The inflammation occurs as a result of an allergic reaction and may produce the following symptoms, which are generally present in both eyes:

. Redness under the eyelids and of the eye overall

. Watery, itchy eyes

. Swelling of the membranes

Skin allergy

Commonly referred to as eczema(atopic dermatitis) is a condition commonly found in infants. It tends to occur in individuals at risk for other allergic conditions( asthma and allergic rhinitis) but is not usually caused by direct allergen exposure. The rash results from a complicated inflammatory process. Common features include the following:

. Dry skin associated with significant itching

. Involvement of the face, behind the elbows, and behind knees, though the rash can occur anywhere.

Hives (urticaria) are skin reactions that appear as red, raised, itchy welts and can occur on any part of the body. Short-lived (acute) hives are often due to an allergic reaction to a food or medication, though they also commonly result from a viral infection in children. Hives that recur over a long period of time(chronic hives) are rarely due to an allergic reaction.

Having an allergy increases your risk of certain other medical conditions, including:





Common refer to as anaphylactic shock, it is a potentially life-threatening allergic reaction that can affect a number of organs at the same time.


If you have severe allergies, you’re at increased risk of this serious allergy-induced reaction. Foods, medications and insect stings are the most common triggers.



Asthma is a respiratory condition that results from inflammation and hyperreactivity of the airways, leading to recurrent, reversible narrowing of the airways.

An immune system reaction that affects the airways and breathing. In many cases, asthma is triggered by exposure to an allergen in the environment(allergy-induced asthma).Asthma can often coexist with allergic rhinitis.

Sinusitis and infections of the ears or lungs.


Do you experience a hive when stung by a bee or do you sneeze whenever you pet a cat? If that’s the case, you may be aware of some of your allergens. However, many times you do not know what is causing your allergy symptoms.

Allergies are diagnosed in three steps:

. Personal and medical history. Allows to have a complete understanding of your symptoms and to find out if there is a family history behind.

. Physical exam. When an allergies is suspected, a close attention will be paid to your ears, eyes, nose, throat, chest and skin during the exam. A chest X-ray and sinuses might requested along a pulmonary function test.

. Tests to determine your allergens such as a skin prick test(SPT), intradermal skin test, blood tests(specific IgE), patch test and physician-supervised challenge test.


The treatment for allergies depends on the particular condition. The best way to prevent allergy symptoms and limit your need for medication is to avoid your allergens as much as possible. This includes removing the source of allergens from your home and other places you spend time.


Here is a short list of prescription and over-the-counter medicines to relieve allergy symptoms:

- Nasal corticosteroids are nose sprays.

- Antihistamines

- Mast cell stabilizers

- Decongestants

- Corticosteroids creams or ointments

- Oral corticosteroids

- Epinephrine

Be sure to discuss with your doctor about all the medicines and avoid self-medication.

Immunotherapy options are also available for some allergy patients. There are two common types, which are allergy shots and sublingual immunotherapy(SLIT)


The above article serves only as reference. Kindly refer to your primary care provider for complete consultation and treatment.

For more details please send email to:


ADD: 396 Hongbaoshi Rd, Changning District, Shanghai, China