Seasonal Allergies (Hay Fever)

What seasonal allergies are

In hay fever, the immune system mistakes harmless pollen grains for a threat and makes IgE antibodies against them. On the next exposure, pollen landing on the lining of the nose and eyes triggers mast cells to release histamine and other chemicals. These cause the sneezing, itching, mucus and swelling within minutes, followed by a later phase of congestion hours afterward.

Despite the name, hay fever does not involve hay or fever. The term dates from the 1800s, when farmworkers noticed symptoms at haymaking time. Medically, it is seasonal allergic rhinitis, often with allergic conjunctivitis of the eyes. People who also react to year-round allergens such as dust mites and pets have perennial allergic rhinitis.

Pollen seasons: what is in the air when

Timing varies with region and weather, and seasons in the US have been getting longer.

Pollen counts are highest on warm, dry, windy days and in the morning in many areas. Rain clears pollen briefly, though thunderstorms can cause sudden spikes and "thunderstorm asthma".

Hay fever symptoms

• repeated sneezing, often in bursts
• runny nose with clear, watery mucus (coryza)
• blocked or stuffy nose
• itchy nose, throat, roof of the mouth and ears
• itchy, red, watery, puffy eyes
• post-nasal drip, throat clearing and cough
• reduced sense of smell
• tiredness, poor sleep and poor concentration
• dark circles under the eyes ("allergic shiners") and, in children, a crease across the nose from rubbing upward

Pollen can worsen asthma and eczema. Some people with birch or ragweed allergy get an itchy mouth after eating certain raw fruits or vegetables, called oral allergy syndrome.

Seasonal allergies vs a cold or COVID-19

Who gets seasonal allergies

Hay fever usually begins in childhood or the teens but can start at any age. Risk is higher with:

• a parent or sibling with allergies, asthma or eczema
• having eczema or asthma yourself
• being male in childhood (the gap narrows in adulthood)
• exposure to tobacco smoke

Diagnosis

Most people are diagnosed from their seasonal pattern and response to treatment. Allergy testing helps identify the specific pollen, especially before starting immunotherapy:

• Skin prick testing: small amounts of allergens are pricked into the forearm. A raised itchy bump within 15 to 20 minutes shows sensitivity.
• Blood tests for specific IgE antibodies, useful if skin testing is not possible.

A positive test means sensitization; it matters only if it matches your symptoms.

Treatment

Medicines

• Steroid nasal sprays (fluticasone, budesonide, mometasone, triamcinolone): the most effective single treatment for nasal symptoms, including congestion. They take several days to reach full effect, so start 1 to 2 weeks before your season and use daily throughout it. Aim the spray slightly outward, away from the middle of the nose.
• Non-drowsy oral antihistamines (cetirizine, loratadine, fexofenadine, levocetirizine): good for sneezing, itching and runny nose, less for congestion. Avoid older sedating antihistamines such as diphenhydramine for regular use, especially in older adults.
• Antihistamine nasal sprays (azelastine, olopatadine): fast-acting. Combination sprays with a steroid work better than either alone.
• Antihistamine eye drops (ketotifen, olopatadine) for itchy eyes.
• Decongestants: pseudoephedrine tablets or oxymetazoline sprays for short-term relief. Use sprays for no more than 3 days to avoid rebound congestion. Oral decongestants can raise blood pressure and are unsuitable with heart disease, high blood pressure or glaucoma.
• Montelukast: sometimes used when asthma coexists, but it carries an FDA warning about mood and behavior changes and is not a first choice for hay fever alone.
• Saline nasal rinses wash pollen out of the nose and reduce symptoms. Use distilled, sterile or previously boiled water.

Follow the label dose for over-the-counter medicines, and ask a pharmacist about choices for children and during pregnancy.

Allergen immunotherapy

For people with severe symptoms despite medicines, immunotherapy retrains the immune system:

• Allergy shots: regular injections over 3 to 5 years.
• Sublingual tablets dissolved under the tongue daily, available for grass, ragweed, and some tree pollens in the US.

Both reduce symptoms and medicine use for years after stopping, and may lower the chance of developing asthma in children.

Reducing pollen exposure

• Check local pollen forecasts and plan outdoor activities for lower-count times.
• Keep windows closed at home and in the car during high-pollen days; use air conditioning with a clean filter.
• Shower and change clothes after time outdoors, and wash your hair before bed.
• Wear wraparound sunglasses.
• Dry laundry indoors during peak season.
• Ask someone else to mow the lawn, or wear a mask (an N95 helps) if you do it yourself.
• Use a HEPA air purifier in the bedroom.

Complications

Uncontrolled hay fever can lead to poor sleep, reduced work and school performance, worsened asthma, sinus infections (acute sinusitis) and ear problems in children.

Frequently asked questions

What are the symptoms of hay fever?

The main symptoms are sneezing, a runny or blocked nose, itchy nose and throat, and itchy, red, watery eyes. Many people also have post-nasal drip, cough, tiredness and poor sleep. Symptoms return at the same time each year and are worse outdoors.

Why are my allergies worse in the fall?

In much of the US, ragweed pollen peaks from mid-August to the first frost, and mold spores rise as leaves decay in damp weather. If your symptoms are worst in autumn, ragweed or mold is likely the trigger.

What is the best treatment for seasonal allergies?

For most people, a daily steroid nasal spray started 1 to 2 weeks before pollen season is the most effective single treatment. A non-drowsy antihistamine and antihistamine eye drops add relief for itching and sneezing. Allergy shots or tablets help severe cases.

How do I know if it's allergies or a cold?

Allergies cause itchy eyes and nose, clear mucus and no fever, and last as long as the pollen is around. A cold often brings a sore throat, mild aches, sometimes a low fever, thicker mucus, and clears within about 10 days.

Can you develop hay fever as an adult?

Yes. Hay fever often starts in childhood, but adults can develop it for the first time, sometimes after moving to a new area with different plants. Symptoms can also ease or change over the years.