What is hay fever?

Rhinitis¹ means “inflammation of the nose.” The nose produces a fluid called mucus, which is normally thin and clear. Mucus helps keep foreign contaminants like dust, allergens, and infectious particles out of the sinuses and lungs. It usually drains down the back of the throat (called postnasal drip, when in larger quantities).

When the nose is irritated, however, it may produce a larger amount of thick, pale yellow mucus. The mucus may then flow to the front of the nose, rather than down the back of the throat, causing a runny nose (rhinorrhea).

There are multiple types of rhinitis². Allergic rhinitis, also known as hay fever³, is caused by airborne allergens (substances that can cause immune responses). This condition causes cold-like symptoms, including a runny nose, sneezing, and itchy eyes. Hay fever symptoms are caused by an allergic response to outdoor and indoor allergens such as pollen, dust, and pet dander.

Symptoms of hay fever often occur during certain times of the year (frequently in the spring and fall) when outdoor molds release their spores and plants like trees, grass, and weeds release pollen into the air.

However, the type of substance you are allergic to will affect when your allergies are the worst, as certain types of plants release pollen at different times in the year.

Hay fever symptoms are the result of the immune system incorrectly recognizing allergens (mold spores, pollen, dander, or other substances) as threats. This causes the defensive release of chemicals such as histamine into the bloodstream. These chemicals are what cause you to feel the effects of allergic rhinitis.

Who can get hay fever?

Allergies are relatively common⁴. Allergic rhinitis affects 10–30% of children and adults in the United States and other industrialized countries. Hay fever is not contagious; however, those who have blood relatives (such as a parent) with seasonal allergies⁵ are more likely to have allergies themselves.

If you have allergies that are caused by seasonally active substances like pollen, the time of year will determine when your allergy symptoms are the worst.

It’s possible to be allergic to more than one type of pollen or mold. Because of this, it can be helpful to familiarize yourself with the times of year when the substances that cause your allergies are most prevalent.

In the mid-Atlantic states of the U.S., for example, tree pollination occurs from February to May, grass pollen is present from May to June, and weed pollen is spread from August to October.

In southern states, allergy season can start as early as January and last as late as November. Again, where you live will affect the time of year during which your allergens are most active.

It’s possible for you to develop seasonal allergies even if you have never had them before. Hay fever can begin at nearly any age—they most commonly develop, however, by the time someone is 10 years old.

Seasonal allergies usually reach their peak in the early 20s, and symptoms often lessen or disappear later in adulthood.

Hay fever symptoms

Hay fever symptoms⁶ can be similar to those of the common cold. The most common symptoms of hay fever include:

• Runny nose and/or nasal congestion
• Watery, red, itchy eyes (allergic conjunctivitis) or an itchy nose, roof of the mouth, or throat
• Sneezing
• Cough
• Swollen skin under the eyes
• Postnasal drip (persistent flow of mucus down the throat)
• Fatigue

While irritating and uncomfortable, symptoms of hay fever are usually not overwhelming and can often be treated with home remedies⁷ and over-the-counter medications.

More severe cases of hay fever may sometimes require treatment with prescription medications, such as nasal sprays and oral medications. If prescriptions prove ineffective, immunotherapy treatment may be used to treat allergies.

Some severe symptoms of hay fever may indicate an underlying problem with your immune system.

You should consult your healthcare provider if:

• You’re unable to relieve your hay fever symptoms
• Allergy medications don’t relieve your symptoms or cause uncomfortable side effects
• You have another condition that can make hay fever symptoms worse, such as nasal polyps, asthma, or frequent sinus infections (acute or chronic sinusitis)

As always, you should see your healthcare provider if you are unsure about your symptoms, or if your symptoms get worse or return after going away.

Hay fever causes

Hay fever can be caused by an allergic reaction to a number of different substances, including those found both indoors and outdoors.

Outdoor (seasonal) factors

Your seasonal allergies may worsen at different times of year, depending on what allergens trigger your symptoms. The following factors may trigger seasonal allergies⁸:

• Tree pollen: Most common in early spring
• Grass pollen: Most common in late spring and summer
• Ragweed pollen: Common in the fall
• Fungi spores: Considered both seasonal and perennial (year-round), these can also grow indoors.

Indoor allergies

Indoor allergies may worsen in the winter when houses are often closed up and have less air circulation. Some indoor allergens include:

• Dust mites
• Cockroaches
• Pet dander
• Mold or fungi spores

Allergy or cold?

Because allergies can present with many of the same symptoms as the common cold, it can be different to tell the two conditions apart.

Unlike allergies, which are caused by an immune response and the release of histamines, colds are caused by viral infections (most frequently, the rhinovirus). Both allergies and viruses are more likely to spread at certain times of the year.

However, allergies occur at the same time each year and last as long as the allergen is present (usually 2–3 weeks per allergen), while a cold lasts as long as it takes for your body to fight off and recover from the infection (usually about 1 week).

Risk Factors

Some people are more susceptible than others to developing hay fever⁹.

The following can increase your risk of developing hay fever:

• Having other allergies or asthma or a blood relative (like a parent or sibling) with allergies or asthma
• Having eczema (atopic dermatitis)
• Living or working in an environment that exposes you to allergens (such as animal dander, dust mites, or mold)
• Having a mother who smoked during the first year of your life

Complications from hay fever

The possible complications from hay fever are usually mild. However, they can be more severe if you suffer from a preexisting condition like asthma.

The most common complications from hay fever include:

• Lessened quality of life: Symptoms of hay fever can cause you to be less productive, and, when severe, can cause you or your child to miss work or school.
• Poor sleep: Severe symptoms of hay fever can make you uncomfortable and make it difficult to fall asleep, causing fatigue or tiredness during the day.
• Worsening asthma: Hay fever can lead to worsened asthma symptoms, such as coughing and wheezing.
• Sinusitis: Chronic (or prolonged) sinus congestion caused by hay fever may increase your likelihood of getting sinusitis (a sinus infection).
• Ear infection: Hay fever can cause middle ear infection (otitis media) in children.

Is hay fever contagious?

Because hay fever is the result of an immune response—not a viral or bacterial infection—it is not contagious.

Contagious illnesses are frequently caught through person-to-person transmission. You can catch a bacteria or virus through particles in the air left behind after someone that is infected coughs, sneezes, or talks. Infected particles floating in the air can be inhaled or land on your nose, eyes, or mouth.

Because droplets containing infectious particles can remain infectious for a few hours, you can pick up bacteria or viruses from objects and surfaces. If you don’t wash your hands before touching your face or eating, these particles can be transferred to you through your eyes, nose, or mouth.

The best way to prevent catching contagious illnesses is by frequently washing your hands with warm, soapy water. When soap and water are not available, use an alcohol-based hand sanitizer.

While you are more likely to develop hay fever if a blood relative also has the condition, you cannot catch allergies from someone else who has them.