Symptoms of Allergies

Symptoms in the eye include redness, itching, tearing, burning, stinging, and watery discharge, although usually not severe enough to require medical attention.

Source: NEI (NIH)1

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Back to: « Allergies

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Allergy Symptoms

Source: NIH News in Health (NIH)2

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“Chronic” coughs lasting 3 weeks or more are often caused by postnasal drip, mucus draining down the back of your throat, from allergies.

Source: NIH News in Health (NIH)3

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Signs of mild or moderate allergic reaction

Signs of severe allergic reaction (anaphylaxis)

Source: Queensland Health4

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Sometimes your skin may have red patches and feel itchy (sometimes called 'hives'). You may also feel hot and sweaty or sneezy or your eyes and nose may be sore, itchy and running (hayfever). Your throat could feel sore and froggy or you may be wheezy when you breathe, or have a cough (asthma).

There are many things that can cause an allergic reaction and reactions may range from mild to severe.

Source: Queensland Health5

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Allergies can cause a variety of symptoms such as a runny nose, sneezing, itching, rashes, swelling, or asthma. Allergies can range from minor to severe.

Anaphylaxis is a severe reaction that can be life-threatening.

Source: MedLinePlus (NIH)6

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It can affect many organs:

Source: MedLinePlus (NIH)7

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Symptoms of an allergic reaction to a food usually develop within a few minutes to an hour after eating the food.

  • If you are allergic to a particular food, you may first feel itching in your mouth as you start to eat the food.
  • Your nose could become stuffy or itchy.
  • You might start sneezing.
  • Your eyes could itch and develop tears.
  • You may get swelling of the lips, face, tongue, throat, or other parts of your body.
  • After the food reaches your stomach, you may have symptoms such as vomiting, diarrhea, or stomach cramps.
  • Your skin could become red, itchy, or develop a rash.

Source: OWH (DHHS)8

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If you have a mild allergic reaction, which could include hives, itching, sneezing, or a runny nose, you should take an antihistamine if it’s available and monitor for more severe symptoms, Dr. Guerrerio said.

Severe reactions include difficulty breathing or low blood pressure, which can cause confusion, paleness, a weak pulse, or a lack of consciousness.

Source: MedLinePlus Magazine (NIH)9

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Airborne Allergy

Source: MedLinePlus Magazine (NIH)10

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If you are allergic to a particular food, you may experience some or all of the following symptoms:

Source: MedLinePlus Magazine (NIH)11

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First Allergic Reaction

Usually, the first reaction to a food allergen occurs when you eat that particular food. Sometimes, exposure can occur without your knowledge, such as when a food allergen is a small part of a larger meal or a mixture of different foods. It is the first exposures that prime the immune system to the food.

Source: MedLinePlus Magazine (NIH)12

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It can have many symptoms and affect different parts of the body. Symptoms can include itching, sneezing, difficulty breathing, and blood circulation problems.

Source: MedLinePlus Magazine (NIH)13

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The symptoms of an allergic reaction depend on the type and severity of the reaction.

Common symptoms include:

A fast pulse and nausea and/or vomiting are less common reactions.

Source: New Zealand Health14

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Symptoms of an allergic reaction

Allergic reactions usually happen quickly within a few minutes of exposure to an allergen.

They can cause:

Most allergic reactions are mild, but occasionally a severe reaction called anaphylaxis or anaphylactic shock can occur. This is a medical emergency and needs urgent treatment.

Read more about the symptoms of allergies.

Source: NHS Choices UK15

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Symptoms of an allergic reaction usually develop within a few minutes of being exposed to something you're allergic to, although occasionally they can develop gradually over a few hours.

Although allergic reactions can be a nuisance and hamper your normal activities, most are mild. Very occasionally, a severe reaction called anaphylaxis can occur.

Main allergy symptoms

Common symptoms of an allergic reaction include:

The symptoms vary depending on what you're allergic to and how you come into contact with it. For example, you may have a runny nose if exposed to pollen, develop a rash if you have a skin allergy, or feel sick if you eat something you're allergic to.

See your GP if you or your child might have had an allergic reaction to something. They can help determine whether the symptoms are caused by an allergy or another condition. Read more about diagnosing allergies.

Source: NHS Choices UK16

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Severe allergic reaction (anaphylaxis)

In rare cases, an allergy can lead to a severe allergic reaction, called anaphylaxis or anaphylactic shock, which can be life-threatening.

This affects the whole body and usually develops within minutes of exposure to something you're allergic to.

Signs of anaphylaxis include any of the symptoms above, as well as:

Anaphylaxis is a medical emergency that requires immediate treatment. Read more about anaphylaxis for information about what to do if it occurs.

Source: NHS Choices UK17

Symptom Onset of Allergies

Symptoms of an allergic reaction to a food usually develop within a few minutes to an hour after eating the food.

Source: OWH (DHHS)18

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Allergic reactions usually happen quickly within a few minutes of exposure to an allergen.

Source: NHS Choices UK19

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  1. Source: NEI (NIH): health/ cornealdisease
  2. Source: NIH News in Health (NIH): issue/ jun2016/ feature2
  3. Source: NIH News in Health (NIH): 2005/ October2005/ docs/ 02capsules.htm
  4. Source: Queensland Health: HealthCondition/ condition/ 1/ 25/ 49/ food-allergy
  5. Source: Queensland Health: HealthCondition/ condition/ 4/ 25/ 166/ allergy
  6. Source: MedLinePlus (NIH): allergy.html
  7. Source: MedLinePlus (NIH): anaphylaxis.html
  8. Source: OWH (DHHS): fitness-and-nutrition/ special-food-issues
  9. Source: MedLinePlus Magazine (NIH): magazine/ issues/ summer17/ articles/ summer17pg9-10.html
  10. Source: MedLinePlus Magazine (NIH): magazine/ issues/ spring15/ articles/ spring15pg26-27.html
  11. Source: MedLinePlus Magazine (NIH): magazine/ issues/ spring11/ articles/ spring11pg24-25.html
  12. ibid.
  13. ibid.
  14. Source: New Zealand Health: your-health/ conditions-and-treatments/ diseases-and-illnesses/ allergies
  15. Source: NHS Choices UK: conditions/ Allergies/ 
  16. Source: NHS Choices UK: conditions/ allergies/ symptoms/ 
  17. ibid.
  18. Source: OWH (DHHS): fitness-and-nutrition/ special-food-issues
  19. Source: NHS Choices UK: conditions/ Allergies/ 

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Note: This site is for informational purposes only and is not medical advice. See your doctor or other qualified medical professional for all your medical needs.