Allergy

What Is an Allergy?

Allergies are an adverse response of the immune system often referred to as atopy. An immune system of allergic people reacts to a usually nontoxic substance such as pollen, mold, animal dander etc. in the environment. This substance is termed as allergen.

Does Everyone Have Allergies?

No, not everyone has allergies. People having strong immune systems do not normally have any allergies. Allergies are caused due to a hyperactive immune system. People sometimes inherit a propensity to be allergic, even though not to any particular allergen. When one parent is allergic, their child has a 50% chance of inheriting allergies. That risk increases to 75% if both parents have allergies.

Allergic Reaction: Causes

Many of us suffer from different types of allergies that are caused by a reaction in your immune system. Allergic reaction may happen due to

Skin contact of poison plants, animal dander, pollen or latex
Injection of bee sting and medication.
Ingestion of medication, nuts and shellfish.
Inhalation of pollen, dust, mold and mild dew and animal dander.

Your body may be allergic to poison ivy from repeated exposure.

Certain foods, vaccines and medications, latex rubber, aspirin, shellfish, dust, pollen, mold, animal dander, and poison ivy are commonly known allergens.

Bee stings, fire ant stings, penicillin, and peanuts are famous for causing striking reactions that can be serious and affect the whole body.

Minor injuries, hot or cold temperatures, exercise, or even emotions may be triggers.

Often, the specific allergen cannot be detected unless you have had experienced a similar reaction in the past.

Allergies and the bent to have allergic reactions are evident in many families. But you may have allergies even if they do not run in your family.

Many people who have one trigger are susceptible to have other triggers as well.

People with certain medical conditions are more inclined to have allergic reactions.

Past history of severe allergic reaction.

Asthma
Lung conditions affecting breathing, such as chronic obstructive pulmonary disease (COPD)
Nasal polyps
Frequent infections of the nasal sinuses, ears, or respiratory tract
Sensitive skin

How the allergic reaction is formed?

The immune system is the body\’s organized defense mechanism against foreign particles, particularly infections. It recognizes and reacts to these foreign elements known as antigens.

Antigens are capable of producing antibodies. Antigens may or may not cause an allergic reaction. Allergens are some antigens that cause an allergic reaction and produces IgE.

When the body is exposed to an antigen, a complex set of reactions occur.

The white blood cells create an antibody specific to that antigen. This is termed as \”sensitization\”. Antibodies or immunoglobulins (IgG, IgM, IgA, IgD), that are particularly targeted against specific foreign substances are defensive and help destroy a foreign particle by attaching to its surface and makes it easier for other immune cells to destroy it. Here are 5 different types; IgA, IgM, IgG, IgD, and IgE. IgE is the allergy antibody.

The aim of the antibodies is to identify and destroy disease and sickness causing substances. In allergic reactions, the antibody is termed as immunoglobulin E, or IgE.

This antibody enables production and release of chemicals and hormones which are called “mediators.”

Histamine is a familiar mediator.

Mediators have impact on local tissue and organs along with activating more white blood cell defenders. It is due to these effects that result in the symptoms of the reaction.

If the release of the mediators is abrupt or extensive, the allergic reaction may appear suddenly with severity.

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Allergy Triggers and symptoms

There are a number of different allergy triggers including pollen, dust mites, mold, animal dander, insect stings, latex, and certain food and medications which are very common. If you have an allergy, your symptoms can vary from mild eye irritation and congestion to a more severe reaction causing general swelling and trouble in breathing.

In case you have asthma, a reaction to any harmful allergy-causing substance can aggravate your asthma symptoms. Still there are some measures you can take to prevent and treat allergy attacks when they occur

Pollen

Exposure to pollen from trees, grasses, and weeds can trigger hay fever or seasonal allergies. Symptoms include:

Sneezing
Runny nose
Nasal congestion
Itchy and watery eyes

It can be treated with over-the-counter products, prescription drugs, and allergy shots. You can prevent symptoms by staying indoors on windy days when pollen counts are high, keeping windows closed, and running the air conditioning.

Animal Dander

Sometimes proteins secreted by oil glands in an animal\’s skin and present in their saliva can cause allergic reactions. The allergy can develop in 2 or more years and symptoms may not subside until months after avoiding contact with the animal. If your pet is the cause behind your allergies, it is better to make your bedroom a pet-free zone, avoid the use of carpets, and wash the animal regularly. A HEPA filter and regular vacuuming may also help. Allergy shots may prove beneficial. Symptoms are quite similar as before; these include:

Sneezing
Nasal congestion
Itchy and watery eyes

Treatments include avoiding exposure to animals causing your allergies when possible. Medications like antihistamines, decongestants, nasal steroids, or others may be helpful. Immunotherapy may be recommended if your allergy symptoms are chronic.

Cockroaches

Ick! Not only are cockroaches eerie, but a protein in their droppings can be a bothersome allergen. It can be difficult to get rid of cockroaches from your home, especially in a hot climate, or if you stay in an apartment where bugs can pass back and forth to a neighboring unit. You may use pesticides; keep a clean kitchen, and repair cracks and holes in floors, walls, and windows to prevent their entry into the home.

Dust Mites

Dust mites are microscopic organisms living in house dust. They flourish in high humid areas and survive on the dead skin cells of humans and their pets, as well as on pollen, bacteria, and fungi. One can prevent dust mite allergies by covering mattresses, pillows, and box springs, using hypoallergenic pillows, washing sheets weekly in hot water, and keeping the house free of dust collecting-items such as stuffed animals, curtains, and carpet. The humidity should not exceed 30% to 45%.

Molds Allergy

Molds are parasitic, microscopic fungi with spores floating in the air like pollen. It is a common trigger for allergies and can be traced in damp areas including basements or bathrooms, as well as in grass, leaf piles, hay, mulch, or under mushrooms. Symptoms of mold allergies can crop up seasonally, especially in the summer and fall or year round if mold is in your home. The symptoms are similar to those of pollen and dust mite allergies including sneezing, congestion, itchy and watery eyes, runny nose, and coughing. There is no variation even in the treatments that are the same as those for dust mites or pollen.

Try to avoid activities that trigger symptoms of mold allergy, such as raking leaves.
Keep windows and doors closed, and confirm that moist places such as the basement and bathrooms are well ventilated. Look for areas of water damage and repair those sections. Keep minimum amount of indoor plants because their soil harbors and promotes mold growth.
Try to avoid activities that trigger symptoms of mold allergy, such as raking leaves.
Keep windows and doors closed, and confirm that moist places such as the basement and bathrooms are well ventilated. Look for areas of water damage and repair those sections. Keep minimum amount of indoor plants because their soil harbors and promotes mold growth.

Insect Sting Allergy

Everyone who gets stung by an insect will experience pain, swelling, and redness around the sting site. However, people allergic to stings can have a severe or even fatal reaction. Symptoms of an insect sting allergy include:

Extensive swelling
Redness from the sting or bite lasting for a week or more
Fatigue
Low-grade fever

Rarely, insect stings may result in a full-body allergic reaction called anaphylaxis. Symptoms of anaphylaxis are:

Difficulty breathing
Hives
Swelling of the face, throat or mouth
Wheezing or difficulty in swallowing
Restlessness and anxiety
Rapid pulse
Dizziness
Sharp drop in blood pressure

People extremely allergic to insect stings and the medicine epinephrine should be treated promptly after being stung to prevent the development of a life-threatening condition

To minimize exposure to insects avoid wearing bright colored clothes and fragrant cosmetics and avail yourself an insecticide. Remember to wear shoes outdoors, and avoid contact to outdoor garbage. If you are stung, remove the stinger. If you are at risk of anaphylaxis, have an epinephrine injection without delay.

Here is a list of some Insects causing allergic reactions:

Various bees
Fire ants
Yellow jackets
Hornets
Wasps

Latex Allergy

Latex gloves prove to be the main common offending product for people having a latex allergy, but a latex allergy can also be triggered by latex in condoms and certain medical devices. Symptoms of latex allergy are as follows:

Skin rash
Eye tearing and irritation
Runny nose
Sneezing
Cough
Wheezing
Shortness of breath
Itching of the skin or nose

Allergic reactions to latex can vary from skin redness and itching to a much more severe reaction called anaphylaxis, which can cause difficulty in breathing, hives, and sudden gastrointestinal problems.

Treatments include:

Removal of the latex product
To alleviate allergy symptoms, antihistamines or epinephrine will be recommended

If a person has a latex allergy, it is important for him/her to wear a Medic Alert bracelet and always carry an emergency epinephrine kit. To prevent a latex reaction, sensitive individuals should avoid latex based products.

Food Allergy

Milk, fish and shellfish, nuts, wheat, and eggs commonly cause allergies. Among vegetables brinjal can cause allergy. A food allergic reaction usually occurs soon after consuming the troublesome food. The symptoms may include:

Asthma
Hives
Vomiting
Diarrhea
Swelling near the mouth

The situation can be severe. Therefore, best try to avoid the offending food altogether; but if exposed, treatment with antihistamines or steroids is recommended. In life-threatening circumstances, an epinephrine injection is required to alleviate symptoms.

Drug Allergy

Some people are allergic to certain drugs, such as penicillin or aspirin. Symptoms can range from mild to life-threatening including a skin rash or hives, itchy eyes, congestion, and swelling in the mouth and throat. The best thing is to avoid the offending drug altogether; however, when exposed; treatment with antihistamines or steroids is prescribed. For coughing and lung congestion, bronchodilators may be prescribed to expand the airways. For more serious symptoms epinephrine may be required.

Fragrance

Fragrances found in various products including perfumes, scented candles, laundry detergent, and cosmetics can cause mild to severe health conditions. For most people, symptoms subside once the scent goes out of range. But for some, repeated exposures boosts the symptoms that occur more often and last longer. However, there’s some debate as to whether fragrance reactions can be considered as a true allergy or simply a response to an irritant.

Toxins interacting with proteins

Another non-food protein reaction, urushiol-induced contact dermatitis, originates after you get contacted with poison ivy, eastern poison oak, western poison oak or poison sumac. Urushiol, is not itself a protein. It acts as a hapten and chemically reacts with, binds to, and even changes the shape of vital membrane proteins on exposed skin cells. The immune system is not able to recognize the affected cells as normal parts of the body, causing a T-cell-mediated immune response. Among these poisonous plants, sumac is the most dangerous. The consequential dermatological response to the reaction between urushiol and membrane proteins is:

Redness
Swelling
Papules
Vesicles
Blisters and streaking

Around 25% of the population will have a severe allergic response to urushiol. Generally, approximately 80% to 90% of adults will develop a rash if they are exposed to .0050 milligrams (7.7×10−5 gr) of purified urushiol but some people are so sensitive that it only requires a molecular trace on the skin to instigate an allergic reaction.

Genetic basis

Allergic diseases are very familial. Identical twins are on the verge of having the same allergic diseases about 70% of the time; the same allergy is evident in about 40% of the time in non-identical twins. Moreover, allergic parents may have allergic children, and their allergies appear to be more severe than those from non-allergic parents. Some allergies, however, are not consistent along genealogies; parents allergic to peanuts may have children allergic to ragweed. It appears that the likelihood of developing allergies is inherited and related to an irregularity in the immune system, but the specific allergen is not.

The risk of allergic sensitization and the development of allergies change with age. Young children are most at risk. Several studies have revealed that IgE levels are highest in childhood and fall quickly between the ages of 10 and 30 years. The peak predominance of hay fever is highest in children and young adults and the rate of asthma is highest in children under 10. On the whole, boys have a higher risk of developing allergy than girls, although for some diseases, namely asthma in young adults, females are more likely to get affected. But this sex differences tend to decline in adulthood. Ethnicity may function in some allergies; however, racial factors have been difficult to separate from environmental influences and changes due to migration. It has been propounded that different genetic loci are responsible for asthma, specifically, in people of European, Hispanic, Asian, and African origins.

There are other important influences including smoking, pollution, infection, and hormones may also cause allergic conditions.

Common allergic conditions and their symptoms and signs

The parts of the body that easily react to allergies include the eyes, nose, lungs, skin, and stomach. Although the various allergic diseases are essentially different, they all happen due to an exaggerated immune response to foreign particles in sensitive people. The following table is an overview of common allergic disorders.

Allergic conditions	Symptoms
Allergic Rhinitis (\”hay fever”) It is the most common of the allergic diseases and refers to seasonal nasal symptoms that are due to pollens. Year round or perennial allergic rhinitis is usually due to indoor allergens, such as dust mites, animal dander, or molds	Runny nose Stuffy nose Sneezing Nasal itching (rubbing) Itchy ears and throat Post nasal drip (throat clearing)
Asthma Asthma is a breathing problem that results from the inflammation and spasm of the lung\’s air passages (bronchial tubes). The inflammation causes a narrowing of the air passages, which limits the flow of air into and out of the lungs. Asthma is most often, but not always, related to allergies.	Shortness of breath Wheezing Coughing Chest tightness
Allergic Eyes Allergic eyes (allergic conjunctivitis) is inflammation of the tissue layers (membranes) that cover the surface of the eyeball and the undersurface of the eyelid.	Redness under the lids and of the eye overall Watery, itchy eyes Swelling of the membranes
Allergic Eczema Allergic http://www.medicinenet.com/script/main/hp.asp (atopic dermatitis) is an allergic rash that is usually not caused by skin contact with an allergen. This condition is commonly associated with allergic rhinitis or asthma.	Itching, redness, and or dryness of the skin Rash on the face, especially children Rash around the eyes, in the elbow creases, and behind the knees, especially in older children and adults (rash can be on the trunk of the body)
Hives Hives (urticaria) are skin reactions that appear as itchy swellings and can occur on any part of the body	Raised red weltst Intense itching Hives or reddish discoloration of the skin
Allergic Shock Allergic shock (anaphylaxis or anaphylactic shock) is a life-threatening allergic reaction that can affect a number of organs at the same time. This response typically occurs when the allergen is eaten (for example, foods) or injected (for example, a bee sting).	Nasal congestion Swelling of the throat Stomach pain, nausea, vomiting Shortness of breath, wheezing Low blood pressure or shock

Diagnosis

Skin testing

For detecting the existence of allergen-specific IgE antibodies, allergy skin testing is preferred over blood allergy tests. It is more sensitive and specific, easy to use, and less pricey.

Skin testing is also termed as \”puncture testing\” and \”prick testing\” due to the series of tiny puncture or pricks made into the patient\’s skin. Little amount of suspected allergens and/or their extracts such as pollen, grass, mite proteins, peanut extract, etc. are introduced to the skin marked with pen or dye (the ink/dye should be carefully selected, lest it cause an allergic response itself). A small plastic or metal device is preferred to puncture or pierce the skin. Sometimes, the allergens are injected \”intradermally\” into the patient\’s skin, with the help of a needle and syringe. Common areas for testing incorporate the inside forearm and the back. If the patient has allergies to the substance, then a visible inflammatory reaction will generally occur within 30 minutes.

Blood testing

Diverse blood allergy testing procedures are also available for detecting allergy to specific substances. This kind of testing is useful to measure a \”total IgE level\” – an estimate of IgE contained within the patient\’s serum. This can be determined using the radiometric and colormetric immunoassays. Radiometric assays include the Radio Allergo Sorbent test (RAST) test method. This method uses IgE-binding (anti-IgE) antibodies labeled with radioactive isotopes for quantifying the levels of IgE antibody in the blood. Other newer methods adapt colorimetric or fluorometric technology instead of radioactive isotopes.

Treatment

There is hardly any cure for allergies, but both over-the-counter and prescription medications are available to help decrease annoying symptoms including nasal congestion and runny nose. These allergy drugs include antihistamines, decongestants, combination medicines, corticosteroids, and others.

Decongestants relieve congestion and are often recommended along with antihistamines for allergies. They are available in nasal spray, eye drop, liquid, or pill form.

Nasal spray and eye drop decongestants can be used for only a few days, since long-term use can actually make the situation worse. Pills and liquid decongestants may be taken for a long time safely.

Steroids, known medically as corticosteroids, decrease inflammation associated with allergies. They prevent and treat nasal congestion, sneezing, and itchy, runny nose due to seasonal or year-round allergies. They can also reduce inflammation and swelling from other types of allergic reactions. Steroids are available as pills (for serious allergies or asthma), inhalers (for asthma), nasal sprays (for seasonal or year-round allergies), creams (for skin allergies) or as an eye drop (for allergic conjunctivitis). Your doctor may recommend a steroid in addition to other allergy medications.

Steroids are highly effectual drugs for allergies, but they must be taken daily to receive the best result, even when you aren\’t feeling allergy symptoms. In addition, it may take 1 to 2 weeks before the full effect of the medicine can be felt. Steroids also have side effects like weight gain, high Blood pressure, cataract, Diabetes, muscle weakness etc.

Bronchodilators relax the muscle bands tighten around the airways. This speedily opens the airways, allowing more air in and out of the lungs, improving breathing

Bronchodilators also clear mucus from the lungs. As the airways get released, the mucus moves more freely and can be coughed out more easily.

Usually 1 or 2 puffs of the inhaler relieve the wheezing and chest tightness due to a mild attack. You may require taking more puffs for severe attacks. Side effects of inhalers include-

High blood pressure

Fast heartbeat

Mast cell stabilizers are useful to deal with mild to moderate inflammation in the bronchial tubes and other allergy symptoms. These medications can also be used to check asthma symptoms during exercise and can be used before being exposed to an allergen when it cannot be ignored. Mast cell stabilizers are available as inhalers for asthma, eye drops to treat allergic conjunctivitis, and nasal sprays to prevent nasal allergy symptoms. Like many drugs it may take time before the full effects are felt.

Side Effects of these drugs are rare, especially for Accolate and Singulair, but may include:

Stomach pain
Stomach upset
Heartburn
Fever
Stuffy nose
Cough
Rash
Headache