Maples—Beyond the Syrup!

 What's up, Forsyth? Our next pollen blog post is here! Thanks to Dr. Gallagher with Allergy and Asthma Center of NC for teaching us all about maple pollen, which are commonly observed in Forsyth County's pollen count this time of year.

Maples—Beyond the Syrup!

Written by Dr. Joel Gallagher, Allergy and Asthma Center of NC, Cone Health Medical Group

Well, the pollen season is officially upon us and in full swing. Today we are going to delve into maple pollen! Although we think a bit more about maples in the fall season when leaves are transitioning into shades of crimson, burnt orange, and yellow ocher, it plays an important part in the spring allergy season as well. My childhood memories of maple involve playing with maple seedpods (called samaras), which resemble tiny helicopter blades. However, before the seedpods take form, we are graced with the maple pollen. Like many of the allergenic springtime pollens, it is the perfect size to enter our airways and cause allergic reactions. This leads to allergic symptoms, including runny nose, sneezing, congestion, itchy/watery eyes, dry cough, and generalized malaise. Its pollen is very allergenic and can travel far distances due to its aerodynamic properties.

Here is a photo of a maple pollen grain under a microscope. These can be anywhere from 25-50 microns in diameter. After staining maple pollen with Calberla's stain, they often look like tiny beach balls. 

Maples also play a role in establishing healthy, diverse forests that support plants important for pollinators, including honeybees. Maples grow in nearly every part of the United States. In some areas, some species are even considered an invasive species. Many cities use them as shade trees since they are fast growing and relatively resilient when it comes to an ability to tolerate adverse conditions. Their widespread nature makes them very difficult to avoid for allergy sufferers.

The use of maples by humans has a long history dating back to the Native Americans. Native Americans had a very holistic approach with nature, using trees, plants, and flowers to fashion things needed for their everyday lives. The maple tree was no exception. Native Americans have been capturing the sweetness of what was known as maple water since before the first European colonists arrived. Early on, they used it as a tonic. It was thought to have medicinal properties. Indeed, it is an excellent source of riboflavin and manganese as well as several amino acids and other essential vitamins and minerals. They also used it as an eyewash, as odd as that may sound, but they did this because they were often exposed to smoke and ash from fires to keep their abodes warm. When European settlers arrived, they realized they could process the maple water more thoroughly to get a thicker syrup and even a sugar that could be used for baking. Maple syrup as we know it did not take off until the 1950s or so, when storage capabilities such as canning made it possible to send maple syrup to a larger customer base across the country.

One common question that we, as allergists, receive is whether patients with maple pollen allergies can safely consume maple syrup. There are case reports of patients experiencing allergies to maple syrup, but they are few and far between. The syrup is predominantly sugar, and IgE (allergy antibodies) are nearly always produced against proteins (which are in the maple pollen as opposed to the maple syrup). However, maple syrup is gathered directly from maple trees, so pollen possibly could be in the syrup depending on how it was processed after collection from the tree. With the heat used to concentrate maple syrup, typically the proteins are degraded and are no longer able to cause allergic reactions. So go ahead and pour that syrup over those pancakes!

Diagnosis is based on allergy testing (skin prick testing with possible confirmatory blood work). Treatment can be accomplished with allergy medications, including allergy pills and nasal sprays. Avoiding the outdoors during the time of the day with high pollen counts (pollen is higher between 10am and 5pm) can be helpful. Changing clothes and showering after spending time outdoors can also decrease pollen exposure. Allergen immunotherapy (allergy shots) can be curative.