Allergy

What are allergies?

Allergies are your body’s reaction to a foreign protein. Usually, these proteins (allergens) are harmless. However, if you have an allergy to a particular protein, your body’s defense system (immune system) overreacts to its presence in your body.

What is an allergic reaction?

An allergic reaction is the way your body responds to an allergen.

If you have allergies, the first time you encounter a specific allergen, your body responds by creating immunoglobulin E (IgE). Your immune system makes antibodies to form IgE.

IgE antibodies bind to mast cells (allergy cells) that live in your skin, respiratory tract (airways) and the mucus membrane in the hollow organs that connect to each other from your mouth to your anus (gastrointestinal or GI tract).

The antibodies find the allergens in your body and help remove them by taking them to the mast cell (allergy cell), where they attach to a special receptor. This causes the allergy cell to release histamine. Histamine is what causes your allergy symptoms.

How common are allergies?

Allergies are very common.

More than 50 million people in the United States have an allergic reaction each year. They’re the sixth-leading cause of long-term illness in the United States.

Who do allergies affect?

Allergies can affect anyone.

You’re more likely to have or develop allergies if your biological parents have allergies.

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

A drug allergy can cause:

• Hives

• Itchy skin

• Rash

• Facial swelling

• Wheezing

• Anaphylaxis

Atopic dermatitis, an allergic skin condition also called eczema, can cause skin to:

• Itch

• Redden

• Flake or peel

Anaphylaxis

Some types of allergies, including allergies to foods and insect stings, can trigger a severe reaction known as anaphylaxis. A life-threatening medical emergency, anaphylaxis can cause you to go into shock. Signs and symptoms of anaphylaxis include:

• Loss of consciousness

• A drop in blood pressure

• Severe shortness of breath

• Skin rash

• Lightheadedness

• A rapid, weak pulse

• Nausea and vomiting

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

Risk Factors:

You might be more likely to develop an allergy if you:

• Have a family history of asthma or allergies, such as hay fever, hives or eczema

• Are a child

• Have asthma or another allergic condition

Complications:

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

• Anaphylaxis. 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 of anaphylaxis.

• Asthma. If you have an allergy, you're more likely to have asthma — 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).

• Sinusitis and infections of the ears or lungs. Your risk of getting these conditions is higher if you have hay fever or asthma.

Treating environmental allergies:

For airborne allergens, such as pollen, dust, and mold spores, additional treatment options include:

• throat lozenges with soothing ingredients, such as menthol, honey, or ginger

• shower and wash all clothing after being exposed to an allergen

• exercise for a few minutes to help reduce nasal congestion

Treating allergies on the skin:

For allergic reactions that cause skin symptoms, including those associated with allergens found in animal saliva, poisonous plants, drugs, chemicals and metals, additional treatment options include:

• Topical corticosteroid creams or tablets. Corticosteroids contain steroids that reduce inflammation and itching. Mild forms of these creams can be found online, and a doctor can prescribe stronger versions.

• Moisturizing creams. Emollient creams with soothing ingredients, such as calamine can treat skin reactions.

• Bite or sting medication. Medication targeted to reduce allergic reactions to insect bites or stings have a similar effect to other allergy medications.

• Ice pack. Applying an ice pack wrapped in cloth to the area for 10- to 15-minute intervals can reduce inflammation.

Treating severe allergies:

People should speak to a professional if they have or suspect that they have severe or chronic allergies.

A doctor or allergy specialist can prescribe medications that contain much stronger doses of the compounds found in OTC products.

Treatment options for chronic or severe allergies include:

• Immunotherapy, or allergy shots. Immunotherapy can be between 90 and 98 percent effective at reducing allergic reactions to insect stings, for instance.

• Prescription asthma medications, such as bronchodilators and inhaled corticosteroids.

• Oral cromolyn can be taken for food allergies.

• Drug desensitization therapy is used for specific allergens.

Natural remedies for allergic reactions:

Many traditional medicine systems use herbal supplements and extracts to both treat and prevent allergic reactions, especially seasonal allergies.

Though there is little scientific evidence to support the use of most alternative or natural remedies, some people may find that some can provide relief from their symptoms.

The American Association of Naturopathic Physicians recommend the following natural treatments for allergies:

• Dietary changes. A low-fat diet high in complex carbohydrates, such as beans, whole grains, and vegetables may reduce allergy reactions.

• Bioflavonoids. These plant-based chemicals found in citrus fruits and blackcurrants may act as natural antihistamines. These can also be taken as supplements.

• Supplements. Flaxseed oil, zinc, and vitamins A, C, and E are suggested to improve allergy symptoms.

• Acupuncture. Acupuncture treatments may help some people to find relief from their symptoms.