What Are Seasonal Allergies?

Medically reviewed by Jurairat J. Molina, MD

Seasonal allergies (allergic rhinitis, hay fever) occur when your immune system has an overactive response to a type of substance called an allergen. Common seasonal allergens include tree pollen, grass pollen, mold, and ragweed (which releases pollen). Pollen is a tiny powder that flowering vegetation like plants, trees, weeds, and grass release as part of their reproductive process. Mold is a fungus that releases tiny spores into the air.

Most plants release pollen in warmer seasons, such as the spring and summer. Ragweed pollen and mold are highest in the late summer and fall.

Seasonal allergies affect 60 million people per year in the United States. About 25% of adults and 19% of children have at least one seasonal allergy. Common symptoms include sneezing, watery eyes, and a runny nose. The most common treatments are antihistamines and nasal (nose) corticosteroids. Those with severe allergies may require allergy testing and advanced treatment.

Seasonal Allergy Symptoms

Seasonal allergy symptoms can range from mild (don’t disrupt daily life) to severe (disrupt multiple daily activities or sleep). The following are characteristic symptoms.

• Sneezing

• Itchy or watery eyes

• Runny or stuffy nose

• Dry, unproductive cough

• Throat irritation

• Feeling unusually tired

• Post nasal drip (mucus dripping down the back of the throat)

What Causes Seasonal Allergies?

When your immune system identifies generally harmless substances, like pollen or mold, as a threat, it releases chemicals called histamines in defense. While the histamines are trying to help your body "fight" the threat, they are causing the inflammation that leads to allergy symptoms.

Allergy season starts for many people in the spring when trees like oak, birch, cedar, and maple release pollen. For others, it begins in late spring or summer as grass pollinates. Mold allergies are more common during rainy seasons but can grow in humid indoor conditions. Fall seasonal allergies are typically due to:

• Ragweed

• Sagebrush

• Lamb’s-quarters

• Mugwort

• Tumbleweed

Ragweed is the most common allergen in the U.S. It blooms and pollinates from August to November, but levels are highest in September.

Risk Factors

Those with a family history of allergies or asthma are at a greater risk of experiencing seasonal allergies. Many people also have other allergy triggers, such as:

• Smoke (cigarette and campfires)

• Insect bites and stings

• Chlorine (in pools)

• Pine trees and wreaths

• Perfume

• Animal dander

The “Farm Effect”

Some studies show that those who live on a farm during their first year of life have a 40% lower risk of developing allergies. This is because farm exposure during infancy reduces your sensitivity to these allergens.

The following factors can influence the severity of allergy symptoms:

• Cool nights and warm days can cause pollen to thrive

• Mold grows in high humidity and heat

• Pollen levels are highest in the morning

• Rain washes away pollen, but levels rise after the rain

• Airborne allergies are more severe on windy days

Diagnosis

If you have seasonal allergy symptoms, your healthcare provider will review your medical history and do a physical exam. The following are additional clues that may cause them to suspect that you have seasonal allergies:

• Mouth breathing (due to nasal congestion)

• Frequent sniffling or throat-clearing

• Dark circles under the eyes (allergic “shiners”)

• Crease in the nose fold (due to frequent nose rubbing)

Your provider may refer you to an allergist—a medical doctor who specializes in allergic conditions such as allergies and asthma.

Your allergist may recommend the following diagnostic tests in severe cases, especially for those who do not respond to treatment:

• Skin print test: A small amount of allergen extract is applied to the surface of your skin with a tiny needle prick. If you are allergic to the substance, you'll develop a small raised bump, redness, or itching at this site.

• Intradermal injection: A tiny amount of allergen is injected under the skin, typically on the forearm. Similarly to the skin print test, you are allergic to the substance if allergy symptoms occur at the injection site.

• Allergen-specific immunoglobulin E (IgE) blood test: This blood test identifies specific allergens and the severity of your seasonal allergies (which can change with time).

Imaging tests like X-rays or computed tomography (CT) scans may also be recommended to rule out other conditions like sinus infections, nasal polyps (non-cancerous growths in the nose), or deviated septum (crooked divider in the nose).

Treatments for Seasonal Allergies

Though there is no cure for seasonal allergies, the following treatments can help manage and alleviate symptoms.

Intranasal (Nose) Corticosteroids

Intranasal corticosteroids are nose sprays that work by calming down the immune response. This reduces swelling and irritation in the nasal passages. They are usually the first line of treatment, and examples include:

• Nascort allergy 24HR (triamcinolone acetonide)

• Rhinocort aqua or allergy (budesonide)

• Beconase AQ, Qnasi (beclomethasone dipropionate)

• Flonase (fluticasone propionate)

• Nasonex (mometasone furoate)

• Veramyst (fluticasone furoate)

Antihistamines

Antihistamines block the histamine your body generates, reducing inflammation (swelling). Benadryl (diphenhydramine) works best for sudden or current allergy symptoms. But it can make you drowsy. Other common preventive antihistamine medications include:

• Zyrtec (cetirizine)

• Allegra (fexofenadine)

• Claritin (loratadine)

Decongestants

Decongestants reduce inflammation in the nasal passages, but it’s important to only use them for a few days to avoid unwelcome side effects and rebound congestion. Examples of oral decongestants are Sudafed PE (phenylephrine) and Silfedrine, Sudafed (pseudoephedrine). Intranasal decongestants include Afrin, Neo-synephrine, Vicks Sinex (xylometazoline), or Astepro (azelastine).

Eye Drops

For itching, watery, or swollen eyes, you can try putting a cool cloth over them for a few minutes. You can also try over-the-counter or prescription eye drops. Types of eye drops include:

• Artificial tears (provides moisture)

• Decongestant to reduce redness (those with glaucoma should avoid these)

• Antihistamine to reduce itching

• Corticosteroid to reduce inflammation

• Nonsteroidal anti-inflammatory drugs (NSAIDs) to reduce inflammation

• Mast cell stabilizers like Cromolyn (sodium cromoglycate) to prevent itching

Leukotriene Receptor Antagonists

Leukotriene receptor antagonists like Singulair (montelukast) are other oral medications that your allergist may suggest. However, studies show they are less effective for seasonal allergies than nasal corticosteroids.

Cromolyn (sodium cromoglycate)

Cromolyn (sodium cromoglycate) is a mast cell stabilizer. This preventive medication stops the release of histamines. It comes as an oral solution, inhaler, or eye drops. Allergists commonly prescribe it to prevent allergies in people with asthma.

Immunotherapy

Immunotherapy is when your allergist gives you minimal doses of an allergen over increase over time to slowly desensitize your body. Some are subcutaneous (under the skin) shots, and others are sublingual (under the tongue). This is a long-term treatment for those with severe allergies who don’t respond to medications.

Xolair (omalizumab)

Xolair (omalizumab) is a subcutaneous injection that prevents immunoglobulin E (IgE)—a type of antibody that your immune system creates—from triggering allergy symptoms. Providers typically reserve it for people with allergic asthma, hives, or nasal polyps that other medications have not been able to control.

Prevention

While you can't avoid exposure to allergens altogether, you can take the following steps to reduce your exposure:

• Monitor your local pollen forecast on the news or a weather app

• Try to stay indoors on high-pollen days

• Delegate lawn work to others when possible (or wear a filter mask when outdoors)

• Avoid touching your eyes while outside, and wash your hands when you go indoors

• Shower and change your clothes after being outdoors

• Brush pets off when they come inside

• Keep windows closed during peak allergy seasons

• Consider using air purifiers in your home

• Change your air conditioning and heater filters frequently and consider anti-allergen filters

• Using allergen-proof bedding

• Wash linens in hot water

• Regularly clean and vacuum your home

• Take anti-allergy medications as directed

Related Conditions

Seasonal allergies can sometimes lead to or be associated with other conditions, such as:

• Asthma: Allergens can be a trigger for asthma, a chronic respiratory condition that causes airway inflammation.

• Eczema (atopic dermatitis): This is an inflammatory skin condition that often occurs with allergies and asthma.

• Sinusitis (sinus infection): This is characterized by sinus swelling (from an infection) that causes facial pain, pressure, and nasal discharge.

• Conjunctivitis or pink eye: Allergies or infections cause inflammation of the conjunctiva (clear lining of the eyes), resulting in redness, itching, and watering.

Living With Seasonal Allergies

Living with seasonal allergies can be challenging, but preventing and managing your symptoms is possible. Try to monitor pollen levels and plan outdoor activities accordingly. It can help to reserve outdoor activities for when pollen levels are lower (in the late afternoon). If your allergy symptoms don’t respond to treatment, consider consulting an allergist for advanced treatment options.

Frequently Asked Questions

Why do I suddenly have allergies?

Allergies can develop with age, immune system changes, or exposure to new or high amounts of allergens. For example, if you move or work outdoors, you may be around different vegetation or animals. Other allergy triggers include stress, smoke, perfume, and respiratory infections.

How do I know it's allergies and I'm not sick?

While allergy symptoms may be similar to a cold or the flu, allergies don’t cause a fever or severe body aches. Other signs of allergies include watery or itchy eyes, sneezing, clear, thin mucus (rather than yellow or thick), and an unproductive (rather than productive) cough. If you have a family history of allergies, exposure to new allergens, or notice a seasonal trend, allergies are most likely the culprit. Thankfully, allergies are not contagious.

Is vitamin C good for allergies?

Oral (by mouth) vitamin C is not a proven cure for seasonal allergies. However, some studies show that intravenous (IV or in the vein) vitamin C reduces allergy symptoms. However, oral vitamin C (from food and supplements) has multiple health benefits, including immune system support. So, as long as your healthcare provider says it’s safe for you, it may be worth trying.

What can I drink for allergies?

Drinking water and staying hydrated can help thin mucus and reduce congestion. Herbal teas such as fig, peppermint, ginger, chamomile, rose hips, nettle, and green tea may help boost your immune system, decrease swelling, and ease a scratchy throat. Drinking warm lemon and honey water may also help.

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