Seasonal allergies affect people only during certain times of the year. Symptoms appear most often during the spring, summer and fall and usually subside during the winter. Grasses, weeds and trees release pollen that – along with molds – is the most common source of symptoms. These symptoms include sneezing, itchy and watery eyes, scratchy throat, runny nose, skin rashes and hives.

The most common seasonal allergy is seasonal allergic rhinitis (SAR), also known as hay fever. SAR is caused by an airborne allergen that occurs only at certain times of the year. Other seasonal allergies include the eye conditions allergic conjunctivitis and vernal conjunctivitis, and the sinus condition allergic sinusitis (frequently a result of allergic rhinitis).

The severity of seasonal allergic rhinitis varies by seasons and geographies. Seasonal allergies are most likely to peak in the spring and summer, but the exact nature and timing of symptoms will depend upon which substance triggers an individual’s allergies. For example, those who are allergic to tree pollen are most likely to suffer symptoms in the spring, and those with ragweed allergies will react most strongly during the summer and fall.

A physician often can pinpoint specific allergens by performing allergy tests. Once allergens have been identified, the patient will be urged to avoid exposure to those allergens as much as possible. If avoidance fails to curb symptoms, allergy medications or allergy shots may be prescribed.

Other allergies related to seasonal allergens include:

• Indoor allergies. Molds, pollens and other seasonal allergens are easily tracked indoors through normal human activity. Therefore, it is common that seasonal allergens become indoor allergens.
  
  
• Cosmetic allergies. In sensitive people, allergic skin rashes can be caused by contact with products designed for seasonal use, such as sunscreen or bug spray.
  
  
• Insect allergies. Exposure to most insects capable of triggering allergic reactions in sensitive people occurs seasonally. These include bees, wasps and fire ants.

Seasonal allergies cause symptoms during certain times of the year as opposed to perennial allergies, in which symptoms occur year round. These patterns are usually predictable from year to year and correspond to periods when pollens or molds are in full bloom. 

Those with seasonal allergies experience symptoms when an allergen gains access to the body, usually through the nose (inhaled). However, allergens can also affect a person if they are ingested (eaten) or come into contact with the skin (touched). People can develop seasonal allergies at any age.

Seasonal allergies are usually triggered when an allergic individual comes into contact with proteins found in certain airborne particles during a certain time of year. These proteins can come from a variety of sources, but usually include:

• Pollens. Small, powdery grains of flowering plants that are involved in fertilization and can easily become airborne. These are most often produced by trees, grass and weeds. Ragweed is a major culprit for the majority of people who suffer from pollen-related symptoms.
  

  

   
• Molds and mildews. Tiny fungus spores that can become airborne. These often thrive outdoors in soil, vegetation and rotting wood. They can be found indoors as well, especially in damp areas, basements and bathrooms. Because molds depend on damp and dark conditions, they have a less predictable season than pollens.
  
  

  

Because the airborne levels of pollen and mold change with the seasons, allergic individuals are more likely to experience symptoms during specific times of the year. Plants begin to bloom and release pollen in the spring, however not all areas of the country begin allergy season at the same time. Some trees begin to pollinate as early as January in the southern United States and April in the northern states. By late spring, grasses are pollinating – followed by weeds in the summer and fall. Leaf mold during the fall is also a major trigger of seasonal allergies. Warmer climates will see outdoor mold spore growth peak by midsummer. “Seasonal” allergies can also be present year-round in some warmer climates.

By contrast people susceptible to indoor molds, dust mites and pet dander usually suffer from perennial allergic rhinitis, which is a form of allergy with symptoms that manifest throughout the year. However, it is important to note that allergens that trigger seasonal allergies can be tracked indoors.

Pollens can also cross-react, creating a condition known as oral allergy syndrome (OAS). In OAS, the body mistakes a substance in food for an allergen to which it is sensitive. The proteins in some foods (usually fresh fruits, vegetables and nuts) are similar to proteins found in some types of pollen. At times when pollen counts are high, people with pollen allergies may experience itching or swelling around the mouth, throat and lips after eating fresh fruits, vegetables or nuts. Patients with this condition must avoid any offending foods.

Symptoms of seasonal allergies will vary depending on how the allergen comes into contact with the body. The most common methods is for an allergen (such as pollen) to be inhaled through the nose into the upper respiratory system. There, it triggers swelling in the sinuses and in the passage leading from the throat to the middle ear in people sensitive to that allergen. This inflammation is called allergic rhinitis (hay fever) or allergic sinusitis depending on the location of the inflammation. Symptoms commonly associated with these conditions include:

• Frequent and prolonged sneezing
• Itchy and runny nose
• Congestion
• Red, watery or itchy eyes
• Coughing

At times, the allergen can come into direct contact with eye membranes, causing inflammation – a condition known as allergic conjunctivitis. This results in a variety of eye-related symptoms. If these symptoms intensify with exposure to wind, dust, bright light, hot weather or physical exertion, it may indicate a form of allergic conjunctivitis called vernal conjunctivitis.

Seasonal allergies may also trigger skin rashes in some people, such as hives or contact dermatitis. Reactions that involve two or more body systems are called anaphylaxis and can lead to potentially life-threatening anaphylactic shock. Though rare in relation to seasonal allergies, anyone experiencing an allergic reaction that involves more than one area of the body or difficulty breathing should seek immediate medical attention.

Seasonal allergy symptoms often vary in severity depending on the individual and the environment. However, they will usually last throughout an entire season. The most severe cases are considered extremely uncomfortable and can make it difficult to carry out even everyday tasks.

A physician is likely to conduct a physical examination and take a complete medical history in trying to diagnose seasonal allergies. Other allergies, asthma and eczema are all conditions that raise the likelihood of a person having seasonal allergies.

Seasonal allergies usually can be diagnosed through allergy skin tests. During this test, trace amounts of a variety of different allergens are introduced to the patient’s skin. For each specific allergen, a different area of skin is used. When an area of skin reacts with a wheal or a raised red bump (skin rashes), the patient is likely allergic to that specific allergen.

Some types of seasonal allergies require specific tests. For example, scrapings of the conjunctiva (the tissue lining the inside of the eyelid) may be performed when diagnosing vernal conjunctivitis. This usually will reveal elevated levels of activated T cells (a white blood cell involved in many immune system functions), eosinophils (a white blood cell involved in allergic reactions) and mast cells. Meanwhile, a physician may look for tenderness over the sinus cavities when trying to diagnose allergic rhinosinusitis.

Several types of medication can address symptoms triggered by seasonal allergies (e.g., antihistamines, corticosteroids).  Some medications are taken after the allergic reaction has occurred, to relieve symptoms. Others can help prevent the onset of symptoms before they occur. Depending on the patient’s specific symptoms and the severity of the condition, medications may be given orally or in the form of eye drops, nasal sprays or injection.

Allergy shots are one form of treatment that can prevent allergy symptoms from occurring for long periods of time. When using this type of immunotherapy, a person is gradually exposed to increasing amounts of a diluted allergen, administered through regular injections over a period of years. Eventually, a person builds up enough of an immunity to the allergen that symptoms are no longer a problem (when encountering that particular allergen).

The most effective way of controlling seasonal allergy symptoms is avoidance. By controlling the environment and minimizing exposure to known allergens, an individual can greatly limit the number and severity of allergic reactions. Though this treatment method is not easy, there are several basic steps that can prevent various seasonal allergies. They include:

• Stay indoors as much as possible during the pollen season (high pollen counts). When leaving the home is necessary, patients should try to put off outdoor activities until late morning because pollen counts are typically highest early in the morning.
  
  
• Stay indoors as much as possible in the evening or following a heavy rain. Mold counts are typically high at these times.
  
  
• Be aware of the local pollen and mold conditions. Pollen and mold reports can provide good indications of the amount of airborne allergens currently found in the air.
  
  
• Avoid outdoor activities as much as possible on hot, dry and windy days. These condition often lead to greater pollen and mold distribution.
  
  
• During allergy season, try to keep windows and doors closed at home and in the car.
  
  
• Use air conditioning in the home and car, which cleans and dries out air.
  
  
• Use an air filter that can remove allergens from the air, such as HEPA filters.
  

  

• Use a dehumidifier to prevent the growth of mold by reducing humidity. These devices are especially helpful when placed in damp areas such as basements and laundry rooms. However, patients must remember to change the water reservoir often to prevent mold growth.
  
  
• Avoid yard work that could stir up pollen and molds – such as mowing the lawn or raking leaves. When people with seasonal allergies do perform these tasks, they should wear filtering masks.
  
  
• Avoid hanging laundry outdoors to dry because pollens can collect on fabrics.
  
  
• Wash pets frequently to minimize the amount of allergens on their skin and coats.
  
  
• Shower frequently to wash airborne allergens from hair and skin.
  
  
• Leave shoes at the door after spending time outdoors to prevent dispersing allergens throughout the home.

In addition, there are steps that can be taken to help prevent specific seasonal allergies. For example, patients can reduce the likelihood of vernal conjunctivitis by wearing wrap-around sunglasses to protect their eyes. Patients who refrain from wearing contact lenses may reduce the sensitivity of their eyes to various allergens.

Preparing questions in advance can help patients to have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions regarding seasonal allergies:

1. What tests will you use to determine if I suffer from seasonal allergies?
   
   
2. What treatments are available to me?
   
   
3. Am I candidate for allergy shots?
   
   
4. During what months should I expect my allergies to flareup?
   
   
5. Will my symptoms completely disappear at certain times of year, or will they just be less intense?
   
   
6. Do I have to take my allergy medications year round, or just at certain times of year?
   
   
7. How can I reduce my exposure to allergens?
   
   
8. Would I benefit from the use of a HEPA filter?
   
   
9. Would I benefit from the use of a dehumidifier?
   
   
10. Are my children at an increased risk for seasonal allergies because I have them?