Seasonal Allergies

In 2021, around 14 million children were diagnosed with seasonal allergic rhinitis (hay fever), making allergies one of the most common health issues in this group.

Unchanged: These allergies are often triggered by environmental factors, especially during periods of high pollen levels. By understanding the causes, symptoms, and triggers of seasonal allergies, individuals can better manage their symptoms and enhance their overall quality of life.

What are Seasonal Allergies?

Seasonal allergies occur when the immune system overreacts to harmless substances like pollen, causing symptoms such as

• Sneezing
• Nasal congestion
• Itchy eyes
• Runny nose

Unlike food or year-round (perennial) allergies, seasonal allergies are triggered during certain times of the year when specific plants release pollen into the air.

These allergic reactions usually peak in the spring, summer, or fall, depending on the individual and their location. Some people experience symptoms for only a short period, while others may endure them for several months.

Hay Fever vs Seasonal Allergies vs Allergic Rhinitis

Seasonal allergies, hay fever, and allergic rhinitis refer to the same condition, but the terminology varies depending on the context:

• Seasonal allergies typically refer to allergies that appear during specific seasons, often spring, summer, or fall, when plants release pollen.

• Hay fever is a more colloquial term that describes seasonal allergic reactions. It originated in the early 19th century when people believed the condition was triggered by exposure to the airborne particles released by freshly cut hay, leading to the term “hay fever.”

• Allergic rhinitis is the medical term that covers both seasonal and perennial (year-round) allergies. It describes inflammation in the nasal passages caused by exposure to allergens such as pollen, dust, or pet dander.

Did you know?

By the end of the 19th century, hay fever was popularly known as the “aristocratic disease.” This came after Dr. John Bostock’s observation that it primarily affected the upper classes, as only those with a delicate disposition were thought to be susceptible. Seaside and mountain resorts, especially in the US, even advertised themselves as allergy-free escapes for those seeking relief!

When Do Seasonal Allergies Start?

They typically start when plants begin to release pollen, and this timing can vary depending on the region and the type of pollen involved. In general:

Though pollen counts are generally lower in winter, some areas with mild climates may experience year-round allergens. Indoor allergens, like dust mites and mold, are more common during this season.

What are the Causes of Seasonal Allergies?

Pollen is the number one cause of seasonal allergies. These tiny, powdery particles are released by plants as part of their reproduction. They are carried by the wind and can be easily breathed in, causing allergic reactions in people who are sensitive to them.

Various plants release pollen at different times of the year, resulting in seasonal allergic responses:

1. Tree Pollen

In the spring, trees release significant amounts of pollen into the air. Birch, in particular, is a major contributor to allergies in the Northeastern and Northern regions of the US. Other trees that can trigger allergic reactions include:

Data Source: AAFA

2. Grass Pollen

Grass pollen is more common in late spring and summer. Common grasses known to trigger allergies are:

• Bahia
• Bermuda
• Fescue
• Johnson
• Kentucky blue
• Orchard
• Rye
• Sweet vernal
• Timothy

In warmer regions, grass pollen can be present all year. Its season may also overlap with those of tree and weed pollens.

3. Weed Pollen

Weeds such as ragweed, pigweed, and sagebrush release pollen in fall. Among these, ragweed is the most common allergen, thriving across the US, particularly in the Eastern and Midwestern regions. A single ragweed plant can produce up to 1 billion pollen grains.

4. Mold Spores

Mold thrives in warm, damp environments and releases airborne spores. Many types of mold grow on decaying logs, fallen leaves, compost piles, and even grasses and grains. Unlike pollen, mold doesn’t die off with the first frost.

Most outdoor molds become dormant during the winter but start growing again in the spring on dead plants affected by the cold. Indoors, mold tends to grow in moist areas such as bathrooms, kitchens, and basements.

Some of the most common allergenic molds include:

• Alternaria
• Aspergillus
• Cladosporium
• Penicillium

Additionally, mold can trigger asthma attacks in individuals with asthma who are allergic to it. Exposure to mold can irritate the eyes, skin, nose, throat, and lungs, affecting both those who are allergic and those who are not.

What are the Symptoms of Seasonal Allergies?

The most common symptoms of seasonal allergies include:

• Runny nose (rhinorrhea), typically with a clear, thin discharge
• Nasal congestion, causing a stuffy nose
• Postnasal drip, where mucus flows from the back of the nose down the throat
• Frequent and sometimes intense sneezing
• Itching in the nose, eyes, ears, or mouth
• Red, watery eyes
• Swelling around the eyes
• Irritability or mood swings
• Fatigue
• Disrupted sleep

If pollen triggers a person’s asthma, they may experience allergic asthma, leading to symptoms such as:

• Coughing
• Wheezing
• Shortness of breath
• Chest tightness or discomfort

While these symptoms are common to many people with seasonal allergies, not everyone experiences all of them. The severity and duration of symptoms can also vary depending on the individual’s sensitivity to allergens and the specific triggers they encounter.

How are Seasonal Allergies Diagnosed?

Seasonal allergies are typically diagnosed by an allergist, though primary care doctors are also qualified to perform the diagnosis. Common diagnostic methods include:

1. Medical History and Symptom Review

A healthcare provider will inquire about a patient’s symptoms, when they occur, and whether they align with certain seasons or environmental changes.

2. Skin Prick Test

One of the most widely used methods for identifying specific allergens involves introducing small amounts of potential allergens into the skin, usually on the forearm or back. If redness or swelling occurs, it suggests an allergic sensitivity to that allergen.

3. Blood Test

In some cases, a blood test, such as the radioallergosorbent test (RAST) or enzyme-linked immunosorbent assay (ELISA), is conducted to measure IgE antibody levels. Elevated IgE levels indicate an allergic reaction.

What Are the Treatments for Seasonal Allergies?

Managing seasonal allergies often involves a combination of prevention strategies and treatment to reduce symptoms. The most common treatment options are:

1. Antihistamines

These medications block the effects of histamine, reducing symptoms such as itching, sneezing, and runny nose. They are available in both over-the-counter and prescription forms.

2. Decongestants

These can help relieve nasal congestion by shrinking the blood vessels in the nasal passages. However, they are not recommended for long-term use due to potential side effects like increased blood pressure.

3. Nasal Corticosteroids

These are effective at reducing inflammation in the nasal passages, which helps alleviate symptoms such as congestion and runny nose. Nasal corticosteroids are typically used daily during allergy season for maximum effectiveness.

4. Leukotriene Inhibitors

These medications work by blocking the action of leukotrienes, which are chemicals in the immune system that contribute to allergy symptoms like inflammation, mucus production, and airway constriction.

Research showed that while leukotriene inhibitors work as well as antihistamines, they are less effective than nasal corticosteroids at reducing symptoms and improving quality of life in those with seasonal allergic rhinitis.

5. Immunotherapy

For people with severe or long-lasting seasonal allergies, immunotherapy may be a suitable option. This treatment works by gradually exposing the immune system to small amounts of the allergen to build tolerance over time. The treatment typically involves a series of doses over 3 to 5 years.

There are two main forms of immunotherapy:

• Subcutaneous immunotherapy (SCIT): The allergens are delivered by injection (sometimes referred to as “allergy shots”).

• Sublingual immunotherapy (SLIT): The allergens are given in the form of drops or tablets, and are kept under the tongue (sublingual) for one or two minutes before they are swallowed.

Helpful Article

Explore our in-depth article on allergy treatments, where we cover the most common medications—from antihistamines to nasal corticosteroids—and how each can effectively relieve your symptoms.

How To Prevent Seasonal Allergies?

Taking a proactive approach is essential for effectively managing seasonal allergies. Below are some strategies from Mayo Clinic to help limit allergen exposure and reduce symptoms:

People living in rural or suburban areas, where plants are more abundant, often face higher pollen exposure than those in urban environments. Additionally, regions with pronounced seasonal changes tend to have higher rates of seasonal allergies.

A 2024 study by the Asthma and Allergy Foundation of America (AAFA) analyzed data from the 100 most-populated US metropolitan areas. Based on the findings, the following cities were ranked as the worst for allergy sufferers:

Note: This ranking was based on pollen levels from trees, grass, and weeds, along with the usage of over-the-counter allergy medications and the availability of allergy specialists.

Final Words

The symptoms of seasonal allergies can be disruptive and uncomfortable. If someone suspects they have seasonal allergies, it’s important to consult with a doctor. A healthcare professional can diagnose the source of the symptoms and develop an appropriate treatment plan. This plan will likely include advice on avoiding specific allergy triggers, as well as recommending over-the-counter or prescription medications to manage symptoms effectively.

For those seeking more information on how to better handle seasonal allergies, our comprehensive guide on allergy treatments provides valuable insight.