Close to 18 million Americans are affected by hay fever, according to the Centers for Disease Control and Prevention (CDC). Hay fever is also known as allergic rhinitis or nasal allergies. Hay fever occurs when your body’s immune system recognizes a normally harmless substance as an intruder. These substances are called allergens. The most common allergens that cause hay fever are pollen released in the air by trees, grass, and weeds. It can also be triggered by allergens in your house like pet dander and dust.
When you are exposed to an allergen that your body interprets as an intruder, your body releases chemicals to act as defense against the allergen. One type of chemical that your body releases is histamine. The release of histamine results in symptoms that are very similar to a cold, like a runny nose and sneezing. Hay fever symptoms can make you miserable and affect your day-to-day activities and your performance at work or school.
Despite its name, hay fever doesn’t mean that you are allergic to hay. It also doesn’t cause a fever. Hay fever is not contagious.
Hay fever symptoms usually start right after you are exposed to the allergen. This is because your immune system mistakenly identifies the substance as something harmful. Your immune system will then begin to produce antibodies to this substance. The antibodies signal your immune system to release certain chemicals, like histamine, into your bloodstream. These chemicals cause a reaction that bring about the symptoms of hay fever.
Hay fever symptoms that start immediately after you’re exposed to a specific allergen include:
- runny nose
- nasal congestion
- watery, red, or itchy eyes
- itchy throat or roof of the mouth
- post-nasal drip
- itchy nose
- sinus pressure and pain
- itchy skin
Symptoms that may develop later on include:
- clogged ears
- sore throat
- decreased sense of smell
- dark circles under the eyes (allergic shiners)
- puffiness under the eyes
Hay fever can also cause many other problems, including:
- poor sleep quality
- worsening asthma symptoms, such as wheezing and coughing, if you have asthma
- reduced quality of life as symptoms may make activities less enjoyable or cause you to be less productive at work and school, or even need to stay home from work or school
- ear infections, especially in children
- allergic conjunctivitis (eye allergy), which occurs when the allergen irritates the conjunctiva, the delicate membrane that covers the eye
- inflammation of the sinuses (sinusitis) due to persistent sinus congestion
Your symptoms may be different at different times of the year. It depends on where you live and what types of allergies you have. Tree pollen, grasses, and weeds, all bloom at different times of the year:
- Tree pollen is more common in the spring.
- Grass pollen is more common in late spring and summer.
- Ragweed pollen is more common in the fall.
- Mold spores can be worse during warmer or more humid weather.
- Pollen allergies can be worse on hot, dry days when the wind carries the pollen.
However, if you are allergic to indoor allergens, you may have hay fever symptoms all year round. Indoor allergens include:
- dust mites
- pet dander
- mold and fungal spores
For some people, mild symptoms are present all year long, but they get worse during certain times of the year. Hay fever symptoms can also be made worse from other irritants. This is because hay fever causes inflammation in the lining of the nose and makes it more sensitive to irritants in the air. These irritants include:
- wood smoke
- air pollution
- tobacco smoke
- aerosol sprays
- strong odors
- changes in temperature
- changes in humidity
- irritating fumes
Although the symptoms of hay fever and the symptoms of the common cold are very similar there are a few differences in the start, duration, and signs of each ailment.
Hay fever begins immediately after exposure to an allergen. Colds begin one to three days after exposure to a virus.
Hay fever lasts for as long as you are exposed to the allergens, typically several weeks. Colds usually last just three to seven days.
Hay fever produces a runny nose with a thin, watery discharge. Colds cause a runny nose with thicker discharge that may be yellow in color.
Hay fever does not cause a fever. Colds typically cause a low-grade fever.
The symptoms of hay fever are almost never immediately dangerous, but they can be very bothersome. See your doctor if any of the following occurs:
- Your symptoms last longer than a week and are bothersome to you.
- Over-the-counter allergy medications aren’t helping you.
- You have another condition, like asthma, that are making your hay fever symptoms worse.
- Hay fever occurs all year round.
- Your symptoms are severe.
- The allergy medications you may be taking are causing bothersome side effects.
- You are interested in learning if allergy shots or immunotherapy are a good option for you.