Everything you need to know about hay fever
It is caused by an allergic response to airborne substances, such as pollen. 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.
Here are some key points about hay fever. More detail is in the main article.
- 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.
- 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.
- Seasonal allergic rhinitis is more common in the spring, summer, and early fall.
- Symptoms are usually caused by allergic sensitivity to pollens from trees, grasses, or weeds, or to airborne mold spores.
- Treatment includes avoiding, eliminating, or decreasing exposure to allergens, medication, and immunotherapy, or allergy shots.
Hay fever is sometimes, but not always, related to pollen.
Symptoms can start at different times of the year, depending on what substance the patient is allergic to.
A person who is allergic to a common pollen will have more severe symptoms when the pollen count is high.
Common symptoms include:
- watery eyes
- itchy throat
- a blocked, itchy, or runny nose
Severe symptoms may include:
- loss of smell and taste
- facial pain caused by blocked sinuses
- itchiness spreading from the throat to the nose and ears
People with asthma may experience more wheezing and breathlessness at times when hay fever symptoms are common.
A range of over-the-counter (OTC) treatments can help manage hay fever. Sometimes, a combination of two or three is best. A physician can advise about options.
Antihistamine sprays or tablets: Commonly available OTC, these stop the release of the chemical histamine. They usually effectively relieve symptoms of a runny nose, itching, and sneezing, but they will not unblock congested sinuses. Older antihistamines can cause drowsiness.
Eye drops: These reduce itching and swelling in the eyes. They are usually used alongside other medications. Eye drops often contain cromoglycate.
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 respond 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. It is usually received in the form of allergy shots or sublingual drops for people whose symptoms are serious and have not cleared up following other treatments.
Immunotherapy may lead to lasting remission of allergy symptoms, and it may help 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.
No herbal remedies are recommended.
During pregnancy, it is important to speak to a doctor before taking any medication, to prevent potential adverse effects on fetal development.
A pinprick test can identify what is causing the allergic reaction.
To specify the correct treatment, a doctor will look at the symptoms and ask 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 amount of a known allergen.
A blood test will show the level of IgE antibodies. This will be high if an allergy is present. The test takes about 20 minutes.
Zero IgE antibodies indicate no sensitivity, while 6 indicates very 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 difficult to complete their daily tasks.
Treatment may not eliminate symptoms, but it can reduce their impact.
An individual cannot prevent the development of an allergy, but people who experience hay fever may find some strategies useful for minimizing the impact.
Here are some tips:
- Be aware of the pollen count during susceptible months. Information is available through the internet and other media. Pollen count tends to be higher on humid and windy non-rainy days and during the early evening.
- Keep windows and doors shut when the pollen count is high.
- Avoid mowing the lawn during susceptible months, choose low-pollen days for gardening, and keep away from grassy areas when pollen counts are high.
- Regularly splash the eyes with cool water, to sooth them and clear them of pollen.
- Shower and change your clothes after coming indoors, when pollen counts are high.
- Use wrap-around glasses to protect the eyes from pollen.
- Wear a hat to prevent pollen from collecting in the hair and then sprinkling down onto the eyes and face.
- Have your car fitted with a pollen filter, and drive with the windows closed at high-count times.
- Do not have flowers inside your home.
- Keep all surfaces, floors, and carpets as dust free as possible.
- Choose a vacuum cleaner with a good filter.
- Use "mite-proof" bedding.
- Use a dehumidifier to prevent mold.
- Keep away from cigarette smoke, and quit, if you are a smoker.
- Wash pets when they come indoors on a high pollen count day, or smooth their fur down with a damp cloth.
- Smear Vaseline around the inside edges of your nostrils, as it helps stop pollen from getting through.
- Ask a physician for a plan, if you know your susceptible time is just around the corner.
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:
- tree pollen in the spring
- grass pollen in late spring and summer
- weed pollen, especially during fall
- 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.
Some factors increase the risk of hay fever.
Genetic factors: If a close 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 have 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 have 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 last three risk factors may be linked to childhood infections.
An infant who has had fewer childhood infections may have a higher risk of autoimmune problems later in life.
There is currently no cure for hay fever. However, symptoms can be managed during the times of the year that have a high pollen count.
For treatment to work in the first year, treatment should be commenced 3 months before the season in which pollen spreads.
Continued treatment can have the effect of reducing symptoms, improving immunity to the allergen, and enhancing the quality of life. Three years of treatment has been shown to lead to long-term desensitization against pollen.
However, if symptoms do not improve significantly after one year, treatment should be discontinued as it is unlikely to work.
Hay fever can become more serious, moving into the lungs and developing into allergic asthma. People with a pollen allergy can also become more likely to develop other allergies, such as food intolerances.
Severe hay fever can also make the mucous membranes of the nose more sensitive to other irritants, such as cigarette smoke or dry air. This can lead to sinusitis.