What are the signs and symptoms of allergies

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.

Sheet final reviewed: 22 November 2018
Next review due: 22 November 2021

Hay fever, or allergic rhinitis, is a common condition with symptoms similar to those of a freezing. There may be sneezing, congestion, runny nose, and sinus pressure.

It is caused by an allergic response to airborne substances, such as pollen.

What are the signs and symptoms of allergies

The time of year it happens depends on what substance, or allergen, the person reacts to.

Despite its name, hay fever does not mean that the person is allergic to hay and has a fever. Hay is hardly ever an allergen, and fever is not a symptom.

Allergic rhinitis is the fifth most common disease in the United States (U.S.).

This article is about hay fever, or allergic rhinitis. You can read about non-allergic rhinitis here.

Fast facts on hay fever

Here are some key points about hay fever.

More detail is in the main article.

  1. Seasonal allergic rhinitis is more common in the spring, summer, and early fall.
  2. Allergic rhinitis, often called hay fever, can cause sneezing, a stuffy or runny nose, watery eyes, and itching of the nose, eyes or the roof of the mouth.
  3. Symptoms are generally caused by allergic sensitivity to pollens from trees, grasses, or weeds, or to airborne mold spores.
  4. In the U.S., 20 million people aged 18 years and over were diagnosed with hay fever in 2016, or 8.2 percent of the adult population. Nine percent of children, or 6.1 million, received a diagnosis.
  5. Treatment includes avoiding, eliminating, or decreasing exposure to allergens, medication, and immunotherapy, or allergy shots.


Hay fever occurs when the immune system mistakes a normally harmless airborne substance for a threat.

The body produces an antibody called immunoglobulin E (IgE) to attack the threat, and it releases the chemical histamine.

Histamine causes the symptoms.

Seasonal hay fever triggers include pollen and spores that only cause symptoms at certain times of the year.

Examples of hay fever triggers include:

  1. weed pollen, especially during fall
  2. tree pollen in the spring
  3. grass pollen in tardy spring and summer
  4. fungi and mold spores, more common in warm weather

Other triggers include pet hair or dander, dust mites, mold, and cockroach dust.

Irritants that can lead to symptoms of hay fever are cigarette smoke, perfumes, and diesel exhaust fumes.

Risk factors

Some factors increase the risk of hay fever.

Genetic factors: If a shut family member has hay fever or another allergy, the risk is higher.

Other allergies or asthma: People with other allergies or asthma are more likely to own hay fever as well.

Gender and age: Before adolescence, hay fever is more common among boys, but after adolescence, females are more affected.

Birth date: People born during the high pollen season own a slightly higher risk of developing hay fever.

Second-hand smoke: Exposure to cigarette smoke during the early years of life increases the risk of hay fever.

Other factors include being the firstborn, coming from a smaller family or a higher-income family.

These final three risk factors may be linked to childhood infections.

An baby who has had fewer childhood infections may own a higher risk of autoimmune problems later in life.

Home treatment

An individual cannot prevent the development of an allergy, but people who experience hay fever may discover some strategies useful for minimizing the impact.

Here are some tips:

  1. Use "mite-proof" bedding.
  2. Regularly splash the eyes with cool water, to sooth them and clear them of pollen.
  3. Keep every surfaces, floors, and carpets as dust free as possible.
  4. Use a dehumidifier to prevent mold.
  5. Smear Vaseline around the inside edges of your nostrils, as it helps stop pollen from getting through.
  6. Have your car fitted with a pollen filter, and drive with the windows closed at high-count times.
  7. Use wrap-around glasses to protect the eyes from pollen.
  8. Keep away from cigarette smoke, and quit, if you are a smoker.
  9. Wash pets when they come indoors on a high pollen count day, or smooth their fur below with a damp cloth.
  10. Keep windows and doors shut when the pollen count is high.
  11. Choose a vacuum cleaner with a excellent filter.
  12. Wear a cap to prevent pollen from collecting in the hair and then sprinkling below onto the eyes and face.
  13. Do not own flowers inside your home.
  14. Be aware of the pollen count during susceptible months.

    Information is available through the internet and other media.

    What are the signs and symptoms of allergies

    Pollen count tends to be higher on humid and windy non-rainy days and during the early evening.

  15. Avoid mowing the lawn during susceptible months, select low-pollen days for gardening, and hold away from grassy areas when pollen counts are high.
  16. Shower and change your clothes after coming indoors, when pollen counts are high.
  17. Ask a physician for a plan, if you know your susceptible time is just around the corner.


Symptoms can start at diverse times of the year, depending on what substance the patient is allergic to.

A person who is allergic to a common pollen will own more severe symptoms when the pollen count is high.

Common symptoms include:

  1. itchy throat
  2. sneezing
  3. watery eyes
  4. a blocked, itchy, or runny nose

Severe symptoms may include:

  1. loss of smell and taste
  2. sweats
  3. facial pain caused by blocked sinuses
  4. headaches
  5. itchiness spreading from the throat to the nose and ears

Some people may experience tiredness or fatigue, irritability, and insomnia.

People with asthma may experience more wheezing and breathlessness at times when hay fever symptoms are common.

Main allergy symptoms

Common symptoms of an allergic reaction include:

  1. swollen lips, tongue, eyes or face
  2. itchy, red, watering eyes (conjunctivitis)
  3. a raised, itchy, red rash (hives)
  4. tummy pain, feeling ill, vomiting or diarrhoea
  5. wheezing, chest tightness, shortness of breath and a cough
  6. sneezing and an itchy, runny or blocked nose (allergic rhinitis)
  7. dry, red and cracked skin

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 own a skin allergy, or feel sick if you eat something you’re allergic to.

See your GP if you or your kid might own had an allergic reaction to something. They can assist determine whether the symptoms are caused by an allergy or another condition.

What are the signs and symptoms of allergies

Read more about diagnosing allergies.


A range of over-the-counter (OTC) treatments can assist manage hay fever. Sometimes, a combination of two or three is best. A physician can advise about options.

Alternative therapies

Alternative therapies that claim to treat hay fever include acupuncture, but study results own not confirmed significant improvements.

No herbal remedies are recommended.

During pregnancy, it is significant to speak to a doctor before taking any medication, to prevent potential adverse effects on fetal development.


These include:

Antihistamine sprays or tablets: Commonly available OTC, these stop the release of the chemical histamine.

They generally effectively relieve symptoms of a runny nose, itching, and sneezing, but they will not unblock congested sinuses.

What are the signs and symptoms of allergies

Older antihistamines can cause drowsiness.

Eye drops: These reduce itching and swelling in the eyes. They are generally used alongside other medications.

What are the signs and symptoms of allergies

Eye drops often contain cromoglycate.

Nasal corticosteroids: These sprays treat the inflammation caused by hay fever. They offer a safe and effective long-term treatment. It may take a week for benefits to show.

Examples include fluticasone (Flonase), fluticasone (Veramyst), mometasone (Nasonex) and beclomethasone (Beconase).

There may be an unpleasant smell or taste, or nose irritation.

Oral corticosteroids: Severe hay fever symptoms may reply well to prednisone tablets, prescribed by a doctor. These are for short-term use only.

Long-term use is linked to cataracts, muscle weakness, and osteoporosis.

Immunotherapy: Immunotherapy can provide long-term relief by gradually desensitizing the immune system to the allergens that trigger the symptoms.

What are the signs and symptoms of allergies

It is generally received in the form of allergy shots or sublingual drops for people whose symptoms are serious and own not cleared up following other treatments.

Immunotherapy may lead to lasting remission of allergy symptoms, and it may assist prevent the development of asthma and new allergies.

Injections are given by a doctor, but sublingual immunotherapy, or medication that is dissolved under the tongue, can be taken at home.


To specify the correct treatment, a doctor will glance at the symptoms and enquire about personal and family medical history.

A blood or skin test can identify which substance the patient is allergic to.

In a skin test, the skin is pricked with a minute quantity of a known allergen.

A blood test will show the level of IgE antibodies.

This will be high if an allergy is present.

What are the signs and symptoms of allergies

The test takes about 20 minutes.

Zero IgE antibodies indicate no sensitivity, while 6 indicates extremely high sensitivity.

Another skin-prick test involves injecting an allergen under the skin and checking for a reaction around 20 minutes later.

What is hay fever?

Hay fever is an allergic reaction to airborne substances, such as pollen.

An allergy happens when the immune system mistakes a harmless substance for a harmful one, and the body releases chemicals to fight it.

This reaction is what causes the symptoms.

Allergens are often common substances that the immune system in most people either does not react to, or reacts only mildly.

However, some people require treatment, because their symptoms make it hard to finish their daily tasks.

Treatment may not eliminate symptoms, but it can reduce their impact.