Plants produce allergens in a couple different ways. Plants like ragweed, grass, chrysanthemums (and other flowers) and trees all produce pollen. Pollen can be carried by animal fur, bees and by air currents. Plants, like stinging nettles, poison ivy, poison sumac and poison oak cause allergic reactions through the oils they secrete. Each type of allergen can cause reactions ranging from mild to severe.
Plant Oils
Poison ivy, oak and sumac produce oils that cause an allergic reaction when they come in contact with the skin. Some people are not affected, while others have reactions ranging from a patch of mild, red irritated skin, to a large red rash with welts and blisters. Touching the affected area may spread the rash to areas that were not in contact with the plant. Stinging nettles also cause similar reactions when touched.
Weeds
Ragweed, pigweed and goldenrod are a few of the weeds that are known to cause allergies, such as hay fever. They cause sneezing, itchy and watery eyes, runny nose and sore throats. These plants are mostly found in rural areas where farming is prevalent. The allergens are transported by various means, but with these plants air and wind currents seem to carry them the farthest distances.
Flowers
Flowers also can cause allergic reactions because of the pollen they produce. Chrysanthemums and others in the "mum" family are some of the most well known. Roses, carnations, and lilies also produce pollen, but at somewhat smaller amounts than other flowers. Sunflowers and dandelions also cause allergic reactions.
Trees
Trees also produce pollen, even if they don't produce what we see as flowers. Trees mostly pollinate at night. Many people who have allergies to trees, will suffer their worst symptoms during the night time hours. Sneezing, sniffling and runny noses are common symptoms for these types of allergies.
Grass
Grass also produces pollen and pollinate at night. Different types of grass are used for different areas. Long grass is used for landscaping, while short, thicker growing grass is used as ground cover and lawns. Each type of grass produces pollen, some more prevalent and irritating than others.
References
- Asthma and Allergy Foundation of America: Overview
- Prescription for Nutritional Healing, Phyllis Balch, 2006
- Mayo Clinic: Allergies
