Allergy, Asthma and Immunology

This is a guide to help you take environmental steps to control your allergy induced symptoms.

Seasonal (outdoor) Allergens – these are present during defined periods of the year. The outdoor allergens that are present and the time they are produced vary substantially between different parts of the country. The outdoor allergens we test for are the most important ones in Southwest Missouri. The times that plants pollinate follow a consistent pattern every year but the levels are impacted substantially by rainfall amounts, humidity, wind and temperature and can vary from year to year.

Tree Pollen – this produced in the late winter and spring. Can reach very high levels in the spring and is the cause of most spring allergy symptoms.

Cedar - Late winter/early spring – locally red cedar is most common. Mountain cedar which cross reacts gets blown from hundreds of miles away (Texas, Oklahoma, and Colorado). As early as late January or February this can cause allergy symptoms from pollen produced further south.

Ash, Birch, Elm, Maple, Cottonwood - Early Spring – March and April these pollens typically reach the highest levels.

Oak, Hickory, Cottonwood, Sycamore, Walnut tree, Pecan tree - Mid/Late Spring. Oak is the most prolific producer of tree pollen in SW Missouri. This usually reaches the highest levels in mid spring around April, but can be present earlier. Tree pollen season can persist into May.

Trees that have large, colorful, showy flowers like dogwoods, Bradford pears, cherry, redbud and crabapples although blooming at the same time as many of the trees above, do not cause allergies! That is because they are insect pollinated (not wind pollinated) so do not produce a large amount of airborne pollen.

Grass Pollen – Grass season is summer, starting in May and persisting through August. The pollen is what causes allergies, not the grass itself.  Grass species are broadly divided into two groups, northern and southern. There is a large amount of cross reactivity between grasses within each group so if you are allergic to one, you will likely react to many of those in the same group

Northern grass – Fescue, Timothy, Johnson – Fescue is the most common grass in SW Missouri, used in lawns and pastures.

                Southern grass – Bermuda grass is the most important pollinator in this group.

Weed Pollen – Weeds produce the most pollen in the fall, but some pollinate in the mid and late summer too. Ragweed is the undisputed king in this group but many of the other weeds produce large amounts of allergy inducing pollen and can be a major problem too.

                Ragweed – Pollinates August until the first hard frost of winter. This weed is very common in fields and pasture, especially disturbed land. Ragweed pollen can blow from hundreds of miles away.

                English Plantain, Pigweed,  Dock/Sorrell, Lambsquarters, Marshelder, Russian Thistle, Kochia – These all produce large amounts of windborne pollen that can cause allergies.

Outdoor Mold – grow in the soil and dead vegetation on the ground and produce highly allergenic spores that become airborne. Proliferate with damp weather. Present in highest levels in the warmer months but can be found outdoors during warm spells in the winter. Mowing grass and kick up large amounts of mold spores that can cause severe problems sometimes blamed on grass allergy. Mold allergy tends to be especially severe in asthmatic individuals.

                Alternaria, Cladosporium – these two outdoor molds reach the highest levels and are the most important outdoor mold allergens. At times mold counts can reach extremely high levels.

                Helminthosporium, Epicoccum,  Fusarium, Cephalosporium, Curvularia  - are other important allergy producing mold species.

Avoidance of outdoor allergens

•  Most important is learning what you are allergic to and avoiding excessive time outside when the levels are highest.

• Outdoor pollen usually is usually worse on dry, warm and windy days. Windborne plants pollinate in the morning so levels tend to be highest then. Mold levels peak after a abundant rain followed by dry, windy weather.

• The American Academy of Allergy, Asthma and Immunology website has an excellent link to check pollen and outdoor mold levels (google search AAAAI and pollen).  

• During pollen season keep the windows in your home and car closed and run the air or heater if needed.

• Change the filter in your home’s furnace or air conditioner monthly with an allergen filter.

Year round (perennial/indoor) Allergens - these are present throughout the year in indoor environments.

Dust mite – These are microscopic mites that live everywhere that humans do. You can not eliminate them completely from your home they are in the cleanest of homes. They live in mattresses, pillows, carpet, upholstered furniture, stuffed animals etc. They produce a highly allergenic protein that causes allergies and is the major allergen in household dust. Minimizing contact can improve allergies with the measures below. It is important to focus on your bedroom first since this is where we get the largest exposure to dust mites.

• Get dust mite proof covers on your pillow and mattress. These are zippered encasings around your pillow and mattress which dust mites and their allergen can not pass through. This is the most important first step. You can buy these from Target, Walmart, department stores, mattress stores and online.

• Minimize extra pillows, blankets on your bed and wash them weekly in hot water with high temperature dry.

• Change the filter in your home’s furnace or air conditioner monthly with an allergen filter. There is not much utility in small room air filters, studies have shown that these just do not move enough air to make a major difference.

• Keep pets out of your bedroom as pet dander is food for dust mites.

• If possible, minimize carpet and upholstered furniture in your home.

Dog dander, Cat dander – Many people do not realize they are allergic to their pets. However, even if you have had a pet in your home long term, you can still become allergic

• There is no allergen free cat or dog. Even non-shedding breeds of dogs produce dander (skin cells) and this is the major allergen.

• With pet dander allergy it is most important to keep the pet out of your bedroom (especially out of the bed).

• Studies have shown that pet dander allergy ( and dust mite allergy) can make seasonal allergies worse. Consistent low-level allergen exposure throughout the year keeps your bodies immune system “primed”, ready to react to seasonal allergens when the season comes around.

• Even if you do not have a pet, studies have shown that environmental exposure to other’s pets can be significant. This is especially true for cat allergen which is very “sticky” and although not visible, transfers easily on clothing to schools, work etc.

Indoor Mold – most important species are Aspergillus and Penicillium. These grow indoors if there are damp spaces or excessive humidity, especially in basements, bathrooms and closets. Usually indoor mold is not a “hidden” problem but if there is wet drywall or damp basement walls, especially if it smells “musty” there probably is significant indoor mold.

• The most important step is to fix the water intrusion or humidity problem. Mold does not grow without moisture.  Fix the leaky roof, windows or plumbing. Use a dehumidifier to reduce humidity. Have your crawl space checked if you have one. Make sure there are no leaks inside the heating and cooling system in your home.

• Treat areas with mold growth with a dilute bleach solution to kill the mold.

• Mold can sometimes grow indoors in the soil of household plants. Minimizing these may help.