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What are Allergies?

Allergies are the world’s most common chronic condition and can cause reactions that range widely from mildly uncomfortable to life-threatening. In summary, an allergy is the reaction of the body’s immune system to a substance that it misinterprets as a threat. The immune system, as a result, produces antibodies that then travel to cells throughout the body and release histamines, resulting in an allergic reaction.
The body interacts with allergens on a regular basis. Under normal circumstances, the body does not have a pro-inflammatory response, resulting in what is known as a Type 1 immune response. In individuals with allergies, however, the body switches over to what is known as a Type 2 immune response when confronted with the allergen. In a Type 2 immune response, the immune system sends in T helper type 2 cells, which results in the production of immunoglobulin (Ig) E molecules that, in turn, trigger the production of histamines and other chemicals.
Developing an allergy happens in stages. When the body is first exposed to an allergen and response with a Type 2 immune response, this is known as allergic sensitization, a process in which the body ‘learns’ to recognize the allergen. As a result, the next time the body is confronted with the allergen, it is ready and waiting to initiate the inflammatory response.

Types of Allergies

There are many different types of allergies, each triggered by its own allergen or category of allergens. The following are some of the most common allergies:

With many allergies, patients can control their exposure to allergens by avoiding certain environments or adhering to certain protocols. With some allergies, however, such as an insect allergy or pollen allergy, the patient can not always control exposure. Seasonal allergies related to pollen can also present only during certain times of the year.


Signs & Symptoms of Allergies

While there are some common symptoms associated with allergies, signs and symptoms of allergies will vary from patient to patient and may depend on the type of allergy involved. For example, a latex allergy might create a skin response while a pollen allergy will generate respiratory symptoms.

General signs and symptoms of allergies include:

  • Allergic rhinitis, i.e. sneezing and an itchy, runny nose
  • Conjunctivitis, i.e. itchy, watery eyes
  • Wheezing and coughing
  • Tightness in the chest
  • Shortness of breath
  • Swollen, tongue, face, eyes, or lips
  • Pain in the stomach
  • Nausea
  • Vomiting or diarrhea
  • Red, rashy or cracked skin

In severe cases, a patient will go into what is known as anaphylaxis. This form of severe allergic reaction is life-threatening and requires immediate medical intervention.

Signs of anaphylaxis include:

  • Swelling in the throat and mouth
  • Difficulty breathing
  • Dizziness and confusion
  • Blue skin and lips
  • Fainting or collapsing

How Long Do Allergy Symptoms Last?

This varies from one type of allergy to the next, and can run anywhere from a few hours to days. In the case of seasonal allergies, symptoms can be present for weeks or even months. If a patient is in anaphylaxis, they should receive immediate medical attention and not wait for the resolution of symptoms.


What Causes Allergies?

What is known is that allergies result from the exposure of the body to an allergen. What is not known is exactly what causes the body to switch from a Type 1 to Type 2 response when confronted with an allergen.

There is a genetic component, however; individuals with an allergic parent have anywhere from a 30 to 50 percent chance of developing an allergy, while individuals with two parents with an allergy can have as high as an 80 percent chance.

Allergies can develop at any point in life. Exposure to new environments or changes in one’s immune system can result in a new allergy in adulthood, for example. Common allergens that trigger an allergic response include:

  • Shellfish
  • Nuts
  • Peanuts
  • Dust
  • Animal or pet dander
  • Insect stings
  • Medications
  • Latex
  • Mold
  • Milk

Who’s at Risk for Allergies?

As mentioned above, those with a family history of allergies are at a higher risk of developing allergies. While many allergies develop during childhood, adults in their 20s and 30s are also at risk of developing allergies. Those with existing asthma are also at a higher risk of developing an allergy.

How Allergies are Diagnosed

Diagnosing an allergy requires a doctor or allergist. The medical professional will take a medical history of the patient, conduct a physical exam, and then administer specific tests based on which allergy is suspected.

Common tests include:

  • Skin tests
  • Blood tests
  • Challenge tests
  • Patch tests

Skin Prick Test, or SPT

Skin testing is one of the most common methods for testing for an allergy. A small amount of the allergen is placed on the skin. The doctor or RN administering the test then pricks the skin in the area lightly. If the patient is allergic to the allergen, a hive-like area will appear at the test site within 15 minutes or so.

Physician-supervised Challenge Test

In a challenge test, the patient ingests a small amount of the allergen by mouth. This is a common method for testing food and drug allergies. IT should only be done by a physician, given the risk of anaphylaxis.

Blood Tests

Blood tests can also be used to test for allergies. A blood sample is taken from the patient and sent to a lab where it is introduced to the allergen. The blood is then tested to see the amount of antibodies it generates in response.

Intradermal Skin Test – In this type of allergy testing, a doctor or RN injects a small amount of the allergen into the skin’s outer layer. This test is used commonly to diagnose drug or venom allergies.

Patch Test

A patch test is typically used to test for allergies when contact dermatitis is present. A patch with a small amount of the allergen is placed on the skin for 48 to 96 hours. Those with an allergy will develop a rash at the site.

How are Allergies Treated?

How to treat allergies depends on the patient’s specific allergy or allergies. There are no known cures for the various allergies, but there are a range of treatments that can address and ameliorate allergy symptoms.

The best preventative treatment is to avoid exposure to an allergen as much as possible. When exposure to an allergen does occur, there are several different treatments that can help with allergies, including shots, oral medications, and drops. The following are some of the most common treatments for allergies:

Nasal Corticosteroids

These nasal sprays are injected directly into the nose, reducing the swelling that causes allergic rhinitis. These medications are most commonly used in the treatment of nasal allergies such as pollen allergies.

Oral Corticosteroids

These medications stop several allergic reactions and reduce swelling. They are powerful medications and require the close supervision of the prescribing physician.


Antihistamines cone in pill, liquid, tablet or spray form and work to block the release of histamines in the body. They are most commonly used to treat indoor or seasonal allergies. Mast cell stabilizers also stop the release of histamines and are used in eye drop or nose spray form.


Epinephrine is delivered to the body via a self-injectable device loaded with a pre-measured dose. It is an essential tool in addressing anaphylaxis. Any patient at risk of anaphylaxis will typically carry one of these devices with them. Epinephrine is commonly used to treat those with insect, food, or drug allergies.

Corticosteroid Creams and Ointments

This type of allergy treatment is used to alleviate the itch and discomfort associated with the skin rashes that can result from some allergies.

When to See an Allergist

Any patient who experiences chronic allergy symptoms should see a doctor or allergist. Common, recurring symptoms that you can experience can include:

  • Coughing
  • Head and nose congestion
  • Red, watery eyes
  • Rashes
  • Shortness of breath


Patients should also seek out the care of an allergist when allergy symptoms interfere with their quality of life or when seasonal allergy symptoms are present several months out of the year.


FAQs About Allergies

How Does an Allergist Diagnose Allergies?

An allergist diagnoses an allergy by taking a medical history, performing a physical exam, and running appropriate tests, including blood, patch or skin tests.

Can Allergies Be Prevented?

The best prevention against allergies is avoiding the allergen in the first place. Research into how to prevent the body from developing an allergic response in the first place is ongoing.

What’s the Difference Between Asthma and Allergies?

Asthma is a chronic lung disease that can be triggered by non-allergic gtriggers, such as stress, cold air, smoke or pollution. Asthma can, however, by triggered by allergens. Those with existing allergies are at a higher risk of developing allergy-induced asthma.

Allergies vs Cold vs Bronchitis

The symptoms of allergies, colds, and bronchitis can be very similar. One critical sign of asthma is that the respiratory difficulty only occurs in the presence of the allergen. Acute conditions such as colds and bronchitis will resolve after a few days or weeks. As with asthma, however, bronchitis can come in an allergy-induced variety.

Does Local Honey Help With Allergies?

Honey has long been lauded for its therapeutic and healing properties. Many ancient cultures used honey as a skin balm for rashes, and some believe that consuming honey can ameliorate allergy symptoms. Research is inconclusive. Any such home remedies should be pursued in consultation with an allergist and should not replace prescribed medications.

Allergy vs COVID symptoms

While COVID can include some of the same respiratory symptoms as some allergies, it also comes with several other symptoms typically that are not present in allergic reactions. These include fever and chills, muscle and body aches, and new loss of taste or smell.