Seasonal Allergies: Symptoms, Causes, and Treatment

Seasonal allergies might mean when you sneeze and cough during certain times of the year.

However, occasional allergies aren’t something you just have to live with. In many areas of the United States, spring allergies begin in February and last until the early summer. Tree pollination begins earliest in the year followed by grass pollination later in the spring and summer and ragweed in the late summer and fall.

In tropical climates, however, grass may pollinate throughout a good portion of the year. Mild winter temperatures can cause plants to pollinate early. A rainy spring can also promote rapid plant growth and increase mold, causing symptoms to last well into the fall.

An allergy (allergic rhinitis) that occurs in a particular season is more commonly known as hay fever. About 8 percent of Americans experience it, reports the American Academy of Allergy, Asthma & Immunology.

Hay fever occurs when your immune system overreacts to an outdoor allergen, such as pollen. An allergen is something that triggers an allergic response. The most common allergens are pollens from wind-pollinated plants, such as trees, grasses, and weeds.

The pollens from insect-pollinated plants are too heavy to remain airborne for long, and they’re less likely to trigger an allergic reaction. Hay fever comes by its name from the hay-cutting season. Historically, this activity occurred in the summer months, around the same time many people experienced symptoms.

Seasonal allergies are less common during the winter, but it’s possible to experience allergic rhinitis year-round. Different plants emit their respective pollens at different times of the year. Depending on your allergy triggers and where you live, you may experience hay fever in more than one season. You may also react to indoor allergens like mold or pet dander.

Symptoms of seasonal allergies range from mild to severe. The most common include:

  • Sneezing
  • Runny or stuffy nose
  • Watery and itchy eyes
  • Itchy sinuses, throat, or ear canals
  • Ear congestion
  • Postnasal drainage


Less common symptoms include:

  • Headache
  • shortness of breath
  • wheezing
  • coughing


Many people with hay fever also have asthma. If you have both hay fever and asthma, your seasonal allergens may trigger an asthma attack.


Causes Of Seasonal Allergies

Hay fever happens when your immune system identifies an airborne substance that’s usually harmless as dangerous. It responds to that substance, or allergen, by releasing histamines and other chemicals into your bloodstream. Those chemicals produce the symptoms of an allergic reaction.


Common triggers of hay fever vary from one season to another.



Trees are responsible for most springtime seasonal allergies. Birch is one of the most common offenders in northern latitudes, where many people with hay fever react to its pollen. Other allergenic trees in North America include cedar, alder, horse chestnut, willow, and poplar.



Hay fever gets its name from hay-cutting season, which is traditionally in the summer months. But the real culprits of summertime seasonal allergies are grasses, such as ryegrass and timothy grass, as well as certain weeds. According to the Asthma and Allergy Foundation of America, grasses are the most common trigger for people with hay fever.



Autumn is ragweed season. The genus name for ragweed is Ambrosia, and it includes more than 40 species worldwide. Most of them grow in temperate regions of North and South America. They’re invasive plants that are difficult to control. Their pollen is a very common allergen, and the symptoms of ragweed allergy can be especially severe. Other plants that drop their pollen in the fall include nettles, mugworts, sorrels, fat hens, and plantains.



By winter, most outdoor allergens lie dormant. As a result, cold weather brings relief to many people with hay fever. But it also means that more folks are spending time indoors. If you’re prone to seasonal allergies, you may also react to indoor allergens, such as mold, pet dander, dust mites, or cockroaches.


There aren’t often major risks stemming from seasonal allergies, but some people can develop further symptoms. These include:

  • Acute or chronic sinusitis (sinus infection): when fluid builds up in your nasal sinuses (the air-filled pockets in the face and within your nose), it allows germs to grow there.
  • Upper respiratory infection: are infections of the mouth, nose and throat, leading to a runny nose, sore throat and cough.
  • Nasal polyps: soft, painless and noncancerous growths lining the nose or sinuses.
  • Postnasal drip: feeling of mucus gathering in the throat or dripping from the back of your nose, leading to frequent swallowing and/or throat clearing, sore irritated throat and feeling a lump in the throat.
  • Ear infections: infection in the ear that can lead to pain, fever and fussiness,


Although not life-threatening, these symptoms can definitely affect the quality of life. More serious cases can develop into bronchitis (a cough due to the airways of the lungs swelling and producing mucus in the lungs) or pneumonia (a serious infection of the lungs that fills them with pus and other liquid). If your bout of seasonal allergies seems to be worsening, Dr. Hemphill suggests following up with your healthcare provider.


Indoor allergens are often easier to remove from your environment than outdoor pollens. Here are a few tips for ridding your home of common allergens:

  • Wash your bedding in very hot water at least once a week.
  • Cover your bedding and pillows with allergen-proof covers.
  • Get rid of carpets and upholstered furniture.
  • Remove stuffed toys from your children’s bedrooms.
  • Fix water leaks and clean up water damage that can help mold and pests flourish.
  • Clean moldy surfaces and any places that mold may form, including humidifiers, swamp coolers, air conditioners, and refrigerators.
  • Use a dehumidifier to reduce excess moisture.


Diagnosing Seasonal Allergies

Hay fever is usually easier to diagnose than other allergies. If you have allergic symptoms that only occur at certain times of the year, it’s a sign that you have seasonal allergic rhinitis. Your doctor may also check your ears, nose, and throat to make a diagnosis. Allergy testing usually isn’t necessary. Your treatment for allergic rhinitis will likely be the same, no matter what type of allergen you react to.


Treating Seasonal Allergies

The best medicine for hay fever and year-round allergic rhinitis is avoidance of allergens that trigger symptoms for you. Medications are also available to treat symptoms of hay fever. Some people also try alternative treatments.



Take steps to avoid seasonal allergens. For instance, use an air conditioner with a HEPA filter to cool your home in summer, rather than ceiling fans. Check your local weather network for pollen forecasts, and try to stay indoors when pollen counts are high. At times of year when your hay fever is active:

  • keep your windows shut
  • limit your time outdoors
  • consider wearing a dust mask when you’re outside, especially on windy days
  • It’s also important to avoid cigarette smoke, which can aggravate hay fever symptoms.



When you can’t avoid your allergens, other treatments are available, including:

over-the-counter decongestants and antihistamines, such as cetirizine (Zyrtec) and combination medications containing acetaminophen, diphenhydramine, and phenylephrine. Prescription medications, such as steroid nasal sprays. In severe cases, your doctor may recommend allergy shots. They’re a type of immunotherapy that can help desensitize your immune system to allergens. Some allergy medications may have unwanted side effects, such as drowsiness, dizziness, and confusion.


Alternative Treatments

Few studies have been done on alternative treatments for hay fever. Some people believe the following alternative treatments may provide relief:

  • quercetin, a flavonoid that gives fruits and vegetables color
  • Lactobacillus acidophilus, the “friendly” bacteria found in yogurt
  • spirulina, a type of blue-green algae
  • vitamin C, which has some antihistamine properties

More research is needed to learn if these alternative treatments are effective.


The symptoms of seasonal allergies can be uncomfortable. If you suspect you have seasonal allergies, talk to your doctor. They can help diagnose the cause of your symptoms and prescribe a treatment plan. They will likely encourage you to take steps to avoid your allergy triggers. They may also recommend over-the-counter or prescription medications.