Seasonal Allergies Causes, Symptoms, and Testing

Symptoms can change from day to day, depending on the weather. For example, high humidity can make mold grow quickly, while pollen counts can surge when it’s warm and windy. Other allergic triggers may be involved, too. Learn more about the symptom threshold.

Allergy season depends on where a person lives and what he or she is allergic to. For example:

• Spring allergies: In some parts of the United States, spring allergy season can start as early as February and last through the summer. It all depends on geographic location and when grasses, trees, and weeds begin pollinating. March and April tend to be known as high spring allergy season months when most people experience the worst of their symptoms.

• Summer allergies: Spring allergy season can continue into the summer months, as grasses and weeds continue to produce pollen. 

• Fall allergies: The fall season can be especially difficult for people who have allergic sensitizations to mold, as mold spores thrive in damp locations such as fallen leaves, dirt, and rotting wood.¹⁰ This time of year is also challenging for those with ragweed sensitization, as ragweed usually begins to pollinate in mid-August and may continue until a hard freeze.¹¹ 

• Winter allergies: Winter allergies can occur if a person is allergic to indoor allergens, such as mold, dust mites, and animal dander, and may worsen during the months of November through January due to increased exposure to these indoor allergens. 

A common cold has similar symptoms to seasonal allergies. However, a reaction to a cold is caused by a virus while a reaction to an allergen is the result of the immune system responding to a substance it has deemed a threat. Learn more about head, eyes, ears, nose, and throat symptoms. 

Five ways to tell your seasonal allergies from a cold:¹²

1. Colds can produce a fever; allergies cannot.  
2. Colds typically don’t cause itchy, watery eyes. Allergies typically do. 
3. Cold symptoms aren’t likely to last more than two weeks, but many people with seasonal allergies will experience symptoms for six weeks at a time.  
4. Sore throats can accompany colds but rarely occur with allergies. 
5. Colds can occur during any season, while seasonal allergy symptoms will likely appear at the same time each year. 

It’s been shown that uncontrolled allergic rhinitis can lead to:^13-15

• Increased risk of developing asthma

• Poorer asthma control in people with asthma (wheezing, breathlessness, nighttime awakenings, limiting daily activities)

• Reduced physical, mental, and emotional wellbeing

• Reduced sleep quality (waking up at night)

• Being constantly tired, and tiring easily, which leads to lowered concentration at work or school and needing more time off, all of which affects job performance or school work

• Reduced quality of everyday life, including social life and daily activities

• Irritability and social problems in children

It is important to consider testing for allergic rhinitis in people with asthma, eczema (atopic dermatitis), conjunctivitis, sinusitis, polyposis, upper respiratory tract infections, otitis media, and sleeping disorders, as well as in children with learning and attention impairments.

More than 80 percent of people with asthma also suffer from rhinitis, suggesting the concept of “one airway, one disease.”^4,16,17 The presence of allergic rhinitis commonly exacerbates asthma, increasing the risk of asthma attacks, emergency visits, and hospitalizations for asthma. It is not clear whether allergic rhinitis represents an earlier clinical manifestation of allergic disease in atopic patients who will later develop asthma or whether rhinitis itself is causative for asthma.^17-20

If a patient suffers from allergic rhinitis triggered by pollen and has an allergic reaction that typically occurs upon ingestion of certain foods, he or she may be experiencing Pollen Food Allergy Syndrome (PFAS), also known as Oral Allergy Syndrome (OAS).²¹ 

Depending on your unique symptom threshold, i.e., the point at which a person experiences symptoms after being exposed to multiple triggers, some allergy symptoms may occur only at certain times throughout the year. For example, common indoor allergens, such as animal dander and mold, may only trigger symptoms in the fall when a person is also exposed to a seasonal allergen, such as ragweed.

While an insect venom allergy  is not technically seasonal, there may be periods of higher exposure to stinging insects during certain times of the year in different geographical locations. It may take several uneventful stings from an insect—such as a bee, wasp, hornet, yellow jacket, or fire ant—for manifestations to appear.

After an initial sting, the immune system of an affected patient may respond by producing Immunoglobulin E (IgE) antibodies. Any subsequent stings can trigger a systemic inflammatory response.²² It is important to correctly identify the culprit insect, as patients can be allergic to one or several species of stinging insects.²² Testing can be used to identify the insects to which a patient is sensitized, which will aid in the selection of the most appropriate treatment.²³