About 20 species of the plantain weed grow in parks, lawns and along roadsides, particularly in the eastern coastal states, the Northwest and California. The dust-like wind-borne pollen produced in copious amounts by plantain is very allergenic and a common cause of hay fever.
Identification
Plantains, in the genus Plantago, are short perennial weeds that produce a flowering spike with small green to brown flowers. Originally from Europe and Asia, plantains grow aggressively throughout the temperate regions of the world. The self-fertilizing plant flowers from April to August. The English plantain sheds the most pollen and, among the plantains, is the major source of allergies.
Allergens
An allergic reaction occurs when the immune system mistakenly identifies a substance as dangerous, such as glycoproteins in plantain pollen. An over-response to protect the body causes the release of antibodies, known as immunoglobulin E, or IgE. These antibodies release histamines that may affect membranes in the eyes, nose and respiratory tract. Plantain pollen contains at least 16 antigens, six of which are capable of causing an allergic reaction. The major allergen is Pla l 1, which has been recognized by the IgE in more than 80 percent of plantain-sensitive patients, according to AllAllergy.net.
Causes and Symptoms
Breathing in pollen is the most common cause of an allergic reaction to weeds such as plantain. If the air is dry or windy, you may be more affected. Airborne allergies and hay fever can cause swelling, inflammation and mucus buildup in the nose. Eyes may become watery, red, itchy and swollen. Other symptoms include sneezing attacks and itchy throat, mouth or ears. You may be at greater risk of developing hay fever if you have an allergy-prone family. Allergies usually start in the early teens, with symptoms peaking after age 20. A similar allergen-provoking protein in grass pollen often causes allergies to tomato, melon and watermelon.
Treatment
Over-the-counter antihistamines in tablet or nasal spray form may help relieve an itchy throat or eyes and runny nose. Anti-allergy nasal sprays and eye drops hinder allergen-caused irritation by acting on the membranes of the nose and eyes. If you are congested, decongestants may help. If symptoms remain severe, consult your doctor. Alternative treatments include desensitization immunotherapy to grass pollen, which involves inducing immune tolerance by injections of minute amounts of allergens.
References
- PollenLibrary.com: Plantain (Plantago)
- AllAllergy.net: English Plantain/Ribwort/Buckhorn Plantain (Weed)
- European Food Information Council; Food Allergy and Food Intolerance; 2006
- Pollen.com; Allergy - The Body's Reaction to Allergens; 2010
- BBC Health; Hay Fever: Causes of Hay Fever; Dr. Adrian Morris
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