What is an allergy?

 

What is an allergy?

An allergy is a hypersensitivity immune response to normally harmless substances, such as pollens or foods. For most people, these substances—also called allergens—pose no problem. In allergic individuals, however, the immune system identifies them as a threat and produces an inappropriate (i.e., abnormal) response. 

When someone is exposed to an allergen and he or she becomes sensitized, the body then produces antibodies called Immunoglobulin E (IgE). The next time the person encounters the same allergen, the allergen binds to the IgE antibodies and causes the mast cell to release histamine and other chemicals. This reaction causes inflammation and triggers allergy symptoms that can range from mild to severe, affecting the skin, gastrointestinal tract, cardiovascular system, and/or respiratory tract.

Symptoms

Allergy symptoms, which depend on the substance involved, can affect your airways, sinuses and nasal passages, skin, and digestive system. Allergic reactions can range from mild to severe. In some severe cases, allergies can trigger a life-threatening reaction known as anaphylaxis.

Hay fever, also called allergic rhinitis, can cause:

·         Sneezing

·         Itching of the nose, eyes or roof of the mouth

·         Runny, stuffy nose

·         Watery, red or swollen eyes (conjunctivitis)

A food allergy can cause:

·         Tingling in the mouth

·         Swelling of the lips, tongue, face or throat

·         Hives

·         Anaphylaxis

An insect sting allergy can cause:

·         A large area of swelling (edema) at the sting site

·         Itching or hives all over the body

·         Cough, chest tightness, wheezing or shortness of breath

·         Anaphylaxis

Causes

An allergy starts when your immune system mistakes a normally harmless substance for a dangerous invader. The immune system then produces antibodies that remain on the alert for that particular allergen. When you're exposed to the allergen again, these antibodies can release a number of immune system chemicals, such as histamine, that cause allergy symptoms.

Common allergy triggers include:

·         Airborne allergens, such as pollen, animal dander, dust mites and mold

·         Certain foods, particularly peanuts, tree nuts, wheat, soy, fish, shellfish, eggs and milk

·         Insect stings, such as from a bee or wasp

·         Medications, particularly penicillin or penicillin-based antibiotics

·         Latex or other substances you touch, which can cause allergic skin reactions

How do I test for allergies?

There are different types of  Allergy tests. The most common allergy tests are skin prick tests and blood tests.

Allergy testing identifies allergens, like mold, pet dander, bee stings and peanuts, that can cause allergies. During a skin prick test, a healthcare provider introduces allergens into your skin to check for a wheal (raised mark), rash or other reactions. Blood tests can check for IgE antibodies. The results can help you take steps to manage allergies.

 

Skin prick (scratch) tests can identify the allergens that cause your allergy symptoms. An allergist will use a thin needle to prick your skin with a tiny amount of different possible allergens. They then check to see if your skin reacts to the allergen.

Blood (IgE) tests can also identify allergies. However, they’re not as sensitive as skin prick tests. Blood tests evaluate IgE antibodies that your immune system produces against a specific protein.

 

How Can I Prevent Allergic Reactions and Manage Allergies?

 

An allergy management plan is key to preventing allergic reactions. It is also necessary to control your allergies. Work with your doctor to create your allergy management plan.

Controlling your allergies and preventing allergic reactions depends on your type of allergy. Here are some ways to manage your allergies:

·         Avoid your allergens. This is very important but not always easy. Some allergens are easier to avoid than others. When you can’t avoid an allergen, try to reduce your contact with it. Learn more about how to manage your specific allergies:

·         Drug Allergy

·         Food allergy

·         Insect Allergies

·         Latex Allergy

 

Drug Allergy

 

·         Many people may use the term “medicine allergy or “drug allergy.” The majority of reactions caused by medications are more correctly termed “adverse reactions to drugs.”

·         True drug allergies are rare and caused by the immune system.

·         An allergic reaction is an abnormal response of the immune system to a normally harmless substance. The job of the immune system is to find foreign substances, such as viruses and bacteria, and get rid of them. Normally, this response protects us from dangerous diseases. People with a drug allergy have an over-sensitive immune system. Their immune system reacts to the drug as if it were an invader.

·         The body’s immune system makes antibodies called Immunoglobulin E (IgE) antibodies.

What Causes an Adverse Reaction to Drugs?

There are two broad categories of adverse reactions to drugs:

1.     True allergic reactions involving the immune system and IgE
(This occurs in a small percentage of people.)

2.     Non-allergic reactions
(These reactions do not involve allergy or immune reaction to the drug.)

 

 

What Are the Signs of an Allergic Reaction Due to Drug Allergy?

 

True allergy to drugs occurs only in a small percentage of people. Other types of immune responses to drugs may also occur.

Classic Allergic Reactions
These reactions occur like other types of allergic conditions such as asthma or hay fever. What is different is that the drug gains access to the whole body rather than just the respiratory tract. Thus, it produces an allergic reaction throughout the body. The classical symptoms of this type of reaction are:

Skin reactions: The most common form of this is hives.

Generalized reaction: This kind of reaction can involve many body systems. This is a serious allergic reaction called anaphylaxis (anna-fih-LACK-sis). Hives are usually present. But, the symptoms also may include:

·         Wheezing (a whistling, squeaky sound when you breathe)

·         Shortness of breath

·         Throat and mouth swelling

·         Nausea

·         Vomiting

·         Diarrhea

·         Cramping abdominal pain

·         Fall in blood pressure

·         Fainting

 

Food Allergies

A food allergy occurs when the body’s immune system sees a certain food as harmful and reacts by causing allergic symptoms. Foods that cause allergic reactions are allergens.

Many adults develop food allergies even without a prior history of allergies.

There is no cure for food allergies. The only way to prevent an allergic reaction is to avoid the food you are allergic to. The good news is with the right steps, you can manage your food allergies and live a full life.

 

 

Insect Allergies

Many people think of warm weather when they think of insect allergies. Warm weather does signal the arrival of some unwanted visitors like stinging and biting insects.

However, you can find two very common “bugs” all year long in homes and buildings. Neither one needs to bite or sting you to cause an allergic reaction, but both trigger allergy and asthma in many people.

 

 

What Kinds of Insects Cause Allergic Reactions?

There are many different kinds of insects or “insect-like bugs” that can cause an allergic reaction:

 

Stinging Insects

Bees, wasps, hornets, yellow-jackets and fire ants are the most common stinging insects that cause an allergic reaction. When these insects sting you, they inject a toxic substance called venom. Most people stung by these insects recover within hours or days. In others, this venom can trigger a life-threatening allergic reaction.

 

Biting Insects

Mosquitoes, kissing bugs, bedbugs, fleas and certain flies are the most common biting insects known to cause an allergic reaction. Most people bitten by insects suffer pain, redness, itching, stinging and minor swelling in the area around the bite. 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. These ticks carry alpha-gal (a sugar). When a tick bites a person, it transfers alpha-gal into the bloodstream. The person’s immune system then reacts to it. Alpha-gal is also found in mammal meat (beef, lamb, pork). If you have allergy symptoms after eating meat, see an allergist.

 

Household Pests

Non-stinging and non-biting insects can also cause allergic reactions, particularly  cockroaches and insect-like dust mites. These two insects may be the most common cause of year-round allergy and asthma. Unlike a 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.

What Are the Signs of an Allergic Reaction to Insects?

Most people stung or bitten by insects suffer pain, redness, itching and minor swelling in the area around the bite or sting. This is a normal reaction. Most people get better within hours or days.

An allergic reaction to insects that don’t sting or bite, like cockroaches or dust mites, is different. You may sneeze, cough, have a runny or stuffy nose, or itchy eyes, nose, mouth or throat. These symptoms can be confused with the common cold, but last for weeks or months at a time. If you have asthma, an allergic reaction could trigger asthma symptoms or an asthma attack.

People can have a serious allergic reaction to stinging or biting insects.

A  life threatening allergic reaction  (anaphylaxis) produces signs and symptoms that require immediate medical attention. Without immediate treatment, anaphylaxis may cause death. Symptoms usually involve more than one organ system (part of the body), such as the skin or mouth, the lungs, the heart, and the gut. Some symptoms include:

·         Skin rashes, itching or hives

·         Swelling of the lips, tongue or throat

·         Shortness of breath, trouble breathing or wheezing (whistling sound during breathing)

·         Dizziness and/or fainting

·         Stomach pain, vomiting, bloating or diarrhea

·         Feeling like something awful is about to happen

Other serious but non-allergic reactions include:

·         A toxic reaction that happens when the body reacts to insect venom like it is a poison. A toxic reaction can cause symptoms similar to those of an allergic reaction. Other symptoms include nausea, fever, fainting, seizures, shock and even death.

·         Serum sickness which is an unusual reaction to a foreign substance in the body. It can cause symptoms hours or days after the sting or bite. Symptoms include fever, joint pain, other flu-like symptoms and sometimes hives.

 

 

 

 

 

Latex Allergy

Latex is a protein found in the sap of a rubber tree grown in Africa and Southeast Asia. The term also refers to natural rubber products made from that sap.

Many everyday products contain latex, such as:

·         Balloons

·         Erasers

·         Condoms and diaphragms

·         Rubber household gloves

·         Medical gloves

·         Catheters

·         Dental products (wedges, orthodontic rubber bands)

·         Elastic in clothing

·         Rubber balls

·         Bandages (adhesives)

·         Foam mattresses and pillows

·         Rubber bands (minor source)

This is just a small number of items that may contain latex.

If you have a latex allergy, you may have an allergic reaction if you come in contact with latex. You may come into contact in different ways. You may have allergic reactions by breathing in latex fibers in the air. You can have allergic reactions if latex touches your skin. You may have an allergic reaction to some fruits that cross-react with latex.