Hay fever season is upon us and for many, this is a time of itchy, watery eyes, sneezing, and congestion. Pollen allergies can be managed by avoiding exposure, but this is often impossible. A range of new medications can offer symptom relief but the most effective allergy management strategy is immunotherapy.
Pollen grains released by trees, grasses, and weeds are carried on the wind. They can cause sneezing, watery eyes, and congestion.
Flowering plants generally do not cause allergies because their pollens are carried by bees.
Avoiding exposure and certain medications can help relieve symptoms.
Immunotherapy requires long-term treatment but the relief is long-lasting without medication.
The incidence of pollen allergies has tripled in the past 25 years, according to a study published in the International Archives of Allergy and Immunology. These pollens can cause a runny nose (allergic rhinitis), itchy and red eyes (conjunctivitis), and eventually may develop into asthma.
Symptoms of a pollen allergy
Some of the common symptoms of pollen allergy include:
- Runny or stuffy nose
- Itchy eyes and nose (sometimes ears and mouth)
- Red, watery eyes (sometimes with swelling around the eyes)
How does pollen cause allergies?
Pollen is what allows plants to reproduce. The tiny pollen grains that cause allergies are generally spread by wind. Flowering plants that spread pollen by bees and other insects do not typically cause allergies.
These small pollen grains are “antigens” that your immune system identifies as “non-self” meaning they are not part of your body. An allergy happens when your immune system overreacts to the presence of this antigen. Think of the sneezing and watery eyes as your body attempts to flush the bothersome antigen away.
When is allergy season?
Pollen allergies are also referred to as “hay fever” or by clinicians as “seasonal allergic rhinitis.” According to the Asthma and Allergy Foundation of America (AAFA), there are three allergy seasons in the United States:
- Tree allergies during the months of February to May
- Grasses between April and June
- Weeds between August and November
How can I tell if I have a pollen allergy?
Most children have 6 to 8 colds per year, and most adults have 2 to 3 colds per year, making it difficult to differentiate common cold symptoms from a pollen allergy. However, if you or your child has allergy symptoms for longer than about two weeks and seem to experience them each year, it is worth checking to see if you have a specific pollen allergy.
There are two types of tests which can be used to detect antibodies to the allergen.
- Skin prick test. A drop of the suspected allergen is placed on your skin then it is scratched into your skin with a needle. If the spot turns red or swells and itches within about 15 to 20 minutes, you may have an allergy. You may also notice a raised, round area — this is a hive or “wheal.”
- IgE blood test. Blood is taken and sent to a laboratory where a small amount of the allergen is added to the sample and the IgE antibody level is measured.
In both cases, simply having a positive test is not necessarily confirmation that the allergen used in the test is what caused your symptoms. This may sound counter-intuitive and frustrating.
The process of identifying which allergen causes your symptoms is by educated guess. You will need to pay attention to when your symptoms happen in daily life, correlate that with the likely pollens in the area, then see if you test positive to that specific allergen.
How to deal with pollen allergies:
Recommendations for dealing with pollen allergies regularly focus on checking pollen forecasts and avoiding exposure using strategies such as carefully planning when to go for a walk or on holiday, using a mask and air purifiers, cleaning the house, washing pets, using a clothes dryer instead of line drying, and keeping home and car windows closed.
But is there scientific evidence to back up these strict recommendations?
Yes, these recommendations do reduce pollen exposures. One discrepancy, though, was the suggestion to avoid wearing contact lenses. Research suggests this may not be necessary.
Consider switching to daily contact lenses
Although contact lenses can cause pollen to stick and irritate the eye, a multi-site cross-over study among 128 individuals compared daily to monthly lenses. Two-thirds of the study participants reported that wearing daily disposable contacts improved their symptoms. Some contacts contain a lubricant and antihistamine, which could help reduce burning and stinging.
Yes, there are a few medications which can reduce symptoms. Some are over the counter and others are available by prescription. According to the AAFA, reducing pollen exposure is an important first step but the following medications may provide additional relief:
- Nasal corticosteroid sprays. These reduce inflammation and are the most effective treatment because they reduce all symptoms of pollen allergies.
- Antihistamines. These block an important immune system first responder, histamine, which causes inflammation and helps your body flush out antigens. Antihistamines are available as a pill, liquid, or spray. They are not as effective as nasal corticosteroid sprays at reducing congestion, but they do reduce sneezing and itching.
- Decongestants. These are only used for short periods of time because they constrict the vessels of the nasal mucosa. Due to this mechanism, they can interact with other drugs used to treat cardiovascular conditions. Check with your doctor before using decongestants if you have a thyroid condition, glaucoma, high blood pressure, or difficulty urinating.
- Leukotriene receptor antagonists. These medications block the receptor that binds to leukotriene, which is an important immune system messenger.
- Cromolyn sodium. This drug blocks histamine and leukotriene via a nasal spray. Cromolyn sodium has few side effects but must be taken four times daily.
Immunotherapy offers the most durable relief
Although “immunotherapy” — training the body to avoid its overreaction to an allergen — has been used for a century, we are gaining much more knowledge about the underlying mechanisms at play, and how to identify specific allergens. Immunotherapy introduces a small amount of the pollen allergen to the body through subcutaneous (under the skin) injection or a newer sublingual (under the tongue) approach.
Training the body to tolerate allergen exposures means that you can reduce the amount of medication needed to manage symptoms.
Another important benefit is the potential to prevent other allergies from developing due to cross-reactivity by the immune system. Cross-reactivity is helpful when the immune system recognizes a closely related virus or bacteria, but for allergy sufferers, it means related allergens can provoke an immune hyper-response and allergy symptom cascade.
Immunotherapy may also prevent the allergy from developing into asthma.
People who have “allergy shots” visit the doctor every week or two initially, then the treatment is administered monthly. The goal is to gradually increase the body’s tolerance to the allergen. This build-up phase can take three to six months. The maintenance phase lasts three to five years.
Symptoms usually improve during the first year of treatment, but by the third year most people are desensitized to the allergen and no longer have any significant reaction.
Treatment can be started in the winter when pollen counts are lower, but it is also possible to start during allergy season. Improvement generally takes two to three years.
Side effects include a mild rash at the injection site, allergic reactions similar to the pollen allergy, itching and swelling in the mouth, fatigue and headache.
Food allergies, such as to peanut butter, are also amenable to immunotherapy, providing a potentially life-saving alternative to avoidance of the trigger food.
Dealing with pollen allergies daily
While immunotherapy offers promising relief, it is a commitment to frequent allergy shots. For busy parents seeking immediate relief, pay attention to pollen counts, follow the recommendations for reducing exposure, and consider switching contact lenses for a few months if applicable. You may also wish to talk to your doctor about allergy testing and seek professional advice regarding which medication may be best for you or your child.
One final, little-known piece of advice published in 1984 is to avoid walking on the sunny side of the street. Theoretically, sunshine increases the temperature of the ground compared to the air and causes convective movement, drawing the warmer air up. This warmer air carries pollen grains that collect on the ground. Even if the benefit is not quite measurable, the placebo effect might be just enough to get a child through the day.
Taking this one step further, urban modeling may be able to generate pollen allergy zones based on trees and plants in the area and aerodynamics around buildings. This 2022 Nature study provides an important step forward for the estimated 1 in 2 people who will be suffering from allergies by 2050 due to increasing pollution and climate change.
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