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An allergy is an immune response or reaction to substances that are usually not harmful.

What causes seasonal allergies?The correct answer is an immune system reaction. Your immune system normally protects your body against harmful bacteria and viruses. If you have seasonal allergies, this system reacts strongly to harmless pollens. Seasonal allergies are also sometimes called hay fever.What are common seasonal allergy symptoms?The correct answer is all of the above. When you come in contact with an allergy trigger, your body releases the chemical histamine. This causes allergy symptoms. Other symptoms include cough, sore throat, puffy eyes, tiredness, and headache. Tell your doctor if you notice allergy symptoms.What else can cause allergy symptoms in some people?The correct answer is A, B, and C. These triggers create symptoms that affect the nose. It's not always easy to know what is causing allergy symptoms. If you start sneezing and your nose runs, write down what you were doing when symptoms started. Learning what causes your symptoms can help you avoid allergy triggers.Your doctor can do tests to find out what causes your allergies.The correct answer is true. Your doctor can test you to see what causes an allergic reaction. The most common is a skin prick test. A small amount of a possible allergy trigger is placed on your skin. Then the skin is gently pricked to allow it to go under the skin. If you have swelling or redness, you are allergic.What can you do to avoid allergy triggers?The correct answer is A, B, and C. To reduce allergy triggers in your home, install furnace filters or other air filters. Use a dehumidifier to dry the air in your house and prevent mold. If you have pets, don't let them in your bedroom or on furniture. Pay attention to pollen levels in your area, and avoid going outside when levels are high.What produces the pollen that causes allergies?The correct answer is all of the above. If you get seasonal allergies, work with your doctor to find out what you are allergic to. Pollen levels are highest on cool, damp, rainy days.The correct answer is false. More pollen is in the air on hot, dry, windy days. The amount of pollen in the air can affect whether hay fever symptoms develop. Check for pollen count in your area in the news or online. Stay indoors in air conditioning if possible when counts are high. Which can treat allergies?The correct answer is all of the above. Common medicines include antihistamines, corticosteroids, and decongestants. Treatments are available over-the-counter and by prescription. Your doctor will recommend a medicine based on what you are allergic to and how severe your allergies are.Allergy shots can treat severe seasonal allergies.The correct answer is true. Your doctor may recommend shots if you can't avoid allergy triggers and your symptoms are hard to control. You will get regular shots of the substance that causes the reaction. Allergy shots help your body adjust and stop reacting to the allergy trigger. Ask your doctor if this therapy is right for you.
Exams and Tests:

The health care provider will perform a physical exam and ask questions, such as when the allergy occurs.

Allergy testing may be needed to find out whether the symptoms are an actual allergy or are caused by other problems. For example, eating contaminated food (food poisoning) may cause symptoms similar to food allergies. Some medications (such as aspirin and ampicillin) can produce non-allergic reactions, including rashes. A runny nose or cough may actually be due to an infection.

Skin testing is the most common method of allergy testing. One type of skin testing is the prick test. It involves placing a small amount of the suspected allergy-causing substances on the skin, and then slightly pricking the area so the substance moves under the skin. The skin is closely watched for signs of a reaction, which include swelling and redness. Other types of skin tests include patch testing and intradermal testing. Skin testing may be an option for some young children and infants.

Blood tests that may be done include:

In some cases, the doctor may tell you to avoid certain items to see if you get better, or to use suspected items to see if you feel worse. This is called "use or elimination testing." This is often used to check for food or medication allergies.

The doctor may also check your reaction to physical triggers by applying heat, cold, or other stimulation to your body and watching for an allergic response.

Sometimes, a suspected allergen is dissolved and dropped into the lower eyelid to check for an allergic reaction. This should only be done by a health care provider.

Support Groups:

Ask your health care provider if there are any asthma and allergy support groups in your area.

Outlook (Prognosis):

Most allergies can be easily treated with medication.

Some children may outgrow an allergy, especially food allergies. But once a substance has triggered an allergic reaction, it usually continues to affect the person.

Allergy shots are most effective when used to treat hay fever and insect sting allergies. They are not used to treat food allergies because of the danger of a severe reaction.

Allergy shots may need years of treatment, but they work in most cases. However, they may cause uncomfortable side effects (such as hives and rash) and dangerous outcomes (such as anaphylaxis). Talk with your provider whether allergy drops (SLIT) are right for you.

Possible Complications:
  • Anaphylaxis (life-threatening allergic reaction)
  • Breathing problems and discomfort during the allergic reaction
  • Drowsiness and other side effects of medicines
When to Contact a Medical Professional:

Call for an appointment with your health care provider if:

  • Severe symptoms of allergy occur
  • Treatment for allergies no longer works

Breastfeeding can help prevent or decrease allergies when you feed babies this way only for 4 to 6 months. However, changing a mother's diet during pregnancy or while breastfeeding does not seem to help prevent allergies.

For most children, changing the diet or using special formulas does not seem to prevent allergies. If a parent, brother, sister, or other family member has a history of eczema and allergies, discuss feeding with your child's doctor.

There is also evidence that being exposed to certain allergens (such as dust mites and cat dander) in the first year of life may prevent some allergies. This is called the "hygiene hypothesis." It came from the observation that infants on farms tend to have fewer allergies than those who grow up in more sterile environments. However, older children do not seem to benefit.

Once allergies have developed, treating the allergies and carefully avoiding allergy triggers can prevent reactions in the future.


Rossen RD, Birdsall HH. Allergy and immunology. In: Harward MP, ed. Medical Secrets. 5th ed. Philadelphia, PA: Elsevier Mosby; 2012:chap 11.

Wasserman SI. Approach to the person with allergic or immunologic disease. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 257.

Review Date: 5/10/2014
Reviewed By: Stuart I. Henochowicz, MD, FACP, Associate Clinical Professor of Medicine, Division of Allergy, Immunology, and Rheumatology, Georgetown University Medical School, Washington, DC. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2002 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

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