What part of ragweed pollen causes human allergies

Keywords : Ragweed, Pollens, Allergy, Biological pest control

Over the final few decades, allergies own become increasingly prevalent in the population in numerous countries, and especially in France. Pollen of the ragweed, which is an invasive exotic plant, causes allergic reactions in numerous people. ANSES is examining several species of ragweed in order to contribute to the prevention and management of their introduction and propagation. It is evaluating the risk of propagation of diverse ragweed species, and has also been asked to assess the risk of introduction of the little Ophraella communa beetle as a biological control solution to ragweed.

Allergies own become increasingly prevalent in the population in numerous countries, including France.

The number of people suffering from allergies has more than doubled in the final twenty years.

Pollen allergies (pollinosis, also known as hay fever or allergic rhinitis) currently affect 15 to 20% of the French population. In a collective expert assessment report published in 2014, ANSES showed that ragweed pollen was among the most problematic plant pollens France. In fact, the pollen from this plant is both highly allergenic (allergy-causing) and an allergen (substance causing an allergic symptom).

Five grains per cubic meter of air are enough to bring about symptoms.

The allergies caused by ragweed pollen happen tardy in the season. They generally start in mid-August, with the greatest intensity in September, stretching on into October.

Several diverse ragweed species of the Ambrosia genus are present in France. The most well-known and widespread species is the common ragweed (Ambrosia artemisiifolia L.) but the giant ragweed (Ambrosia trifida L.) is also found, as well as the perennial ragweed (Ambrosia psilostachya DC.).

These types of ragweed are exotic invasive species.

In fact, they were introduced into Europe from America, which is their natural range, via contaminated batches of cereal seed.

What is allergic disease?

Approximately 50 million Americans suffer from some form of allergic disease. Allergic disease can develop at any age, and heredity plays a key role in who will develop it. If one parent has allergic disease, the estimated risk of the kid to develop allergies is 48%, and the child’s risk grows to 70% if both parents own allergies.

Symptoms of allergic disease are the result of events occurring in your immune system — the body’s defense mechanism against harmful substances.

The body of an individual with allergic disease identifies some substances, called allergens, as harmful. These substances, which are harmless to most people, trigger allergic reactions within that person’s immune system.

When someone predisposed to allergic disease encounters an allergen to which they are sensitive, a chain of events occurs.

What part of ragweed pollen causes human allergies

The primary culprit instigating these events in people with allergies is an antibody called Immunoglobulin E, or IgE. IgE «defends» the body by seeking to remove the offending allergen(s) from the body’s tissues and bloodstream. The first time an allergen enters an allergic person’s body, IgE antibodies are produced in response. These antibodies then travel to cells called mast cells, attach themselves to these cells, and wait for the next time the allergen(s) enters the system.

When they do, the IgE antibodies «capture» the allergens, essentially removing them from circulation.

The mast cells then help further by releasing special chemicals called mediators. These mediators produce the classic symptoms of allergic reactions — swelling of body tissues, sneezing, wheezing, coughing and other symptoms. Due to the complexity of allergic disease, it is not yet fully understood why some substances trigger allergies and others do not, nor why every person does not develop an allergic reaction after exposure to allergens.

What is an allergy?

When your body comes in contact with a virus or bacteria the immune system protects your body by producing antibodies and other substances to fight off these invaders.

An allergy or an allergic reaction is when the immune system recognizes a harmless substance as an invader and tries to protect the body from it. The antibody in this case that is produced is called immunoglobulin E, or IgE.

Tips to Remember: Role of the Allergist/Immunologist

If you own been diagnosed with asthma or allergies, your physician will likely refer you to an allergist/immunologist for care.

What part of ragweed pollen causes human allergies

You may wonder: What is allergic disease? How can an allergist/immunologist help? This sheet is intended to provide information on allergic disease and on the role that an allergist/immunologist plays in the appropriate management and treatment of these diseases.

What is an allergy attack?

When IgE is produced it is specific to the allergen. What that means is if you are exposed to cat and your body mistakes it as something harmful to you your immune system produces anti-cat IgE antibody.

If you are also allergic to dust your produce an IgE antibody to dust. Each time IgE is produced, the IgE molecules attach themselves to mast cells that are found in large numbers in the eyes, nose, lungs, intestines, and immediately beneath the skin. These mast cells contain numerous chemicals, including a substance called histamine which, when released into the body, can cause runny nose, sneezing, watery eyes, itching, hives, and wheezing. These are the symptoms that people who suffer from allergies live with.

In some cases, reactions can happen in several places throughout the body.

Welts or hives may appear, spasm in the lungs may cause coughing or wheezing, the throat and tongue may swell; if anaphylaxis (severe allergic reaction) occurs, it may be fatal.


Pollens are the tiny, egg-shaped male cells of flowering plants. These microscopic, powdery granules are necessary for plant fertilization. The average pollen particle is less than the width of an average human hair.
Pollens from plants with bright flowers, such as roses, generally do not trigger allergies. These large, waxy pollens are carried from plant to plant by bees and other insects. On the other hand, numerous trees, grasses and low-growing weeds own little, light, dry pollens that are well-suited for dissemination by wind currents.

These are the pollens that trigger allergy symptoms.

Seasonal allergic rhinitis in the early spring is often triggered by the pollens of such trees as oak, western red cedar, elm, birch, ash, hickory, poplar, sycamore, maple, cypress and walnut. In the tardy spring and early summer, pollinating grasses-including timothy, bermuda, orchard, sweet vernal, red top and some blue grasses-often trigger symptoms.

In addition to ragweed-the pollen most responsible for tardy summer and drop hay fever in much of North America-other weeds can trigger allergic rhinitis symptoms. These weeds include sagebrush, pigweed, tumbleweed, Russian thistle and cockleweed.

Each plant has a period of pollination that does not vary greatly from year to year.

However, weather conditions can affect the quantity of pollen in the air at any given time. The pollinating season starts later in the spring the further north one goes. Depending on where you live in the United States, the pollen season can start as early as January (in the southern states). Generally, the pollen season lasts from February or March through October.

What part of ragweed pollen causes human allergies

Trees pollinate earliest, from tardy February through May, although this may fluctuate in diverse locations-starting in April in the northern United States to as early as January in the south. Grasses follow next in the cycle, beginning pollination in May and continuing until mid-July. Weeds generally pollinate in tardy summer and early fall.

Ophraella communa: a beetle to control ragweed?

Ophraella communa, whose common name is the ragweed leaf beetle, belongs to the Chrysomelidae family of leaf beetles. Originating in North America, this beetle feeds on plants of the Asteraceae family to which the ragweed species belong, as well as cultivated plants such as the sunflower and the Jerusalem artichoke.

This insect was sighted for the first time in Europe in the summer of 2013 on common ragweed plants in a large area spanning from parts of northern Italy to southern Switzerland.

In the framework of the two formal requests for assessment of the risks linked to the natural introduction of O.

communa and those associated with its use in biological pest control, ANSES has concluded that the risk of O. communa with regard to sunflower and Jerusalem artichoke crops, and more widely for the environment as a whole, has been found to be acceptable. However, the oligophageous nature of O. communa requires prudence as to its use as an inundative release biological control agent. ANSES recommends that surveillance of O.

What part of ragweed pollen causes human allergies

communa introduction be conducted and that sunflower crops be monitored if O. communa introduction is found to own occurred.

ANSES assessment of pollen in ambient air

In 2014, ANSES produced a full report on the current state of knowledge of pollen in ambient air in mainland France. This assessment work has shown that:

  1. The most problematic pollens in France come from true grasses (Gramineae), the birch family of trees (Betulaceae), ragweed and the cypress (Cupressaceae) family of trees (including cypress, thuya and juniper, for example);
  2. It is not currently possible to determine a level at which effects will appear for a given type of pollens, due to the fact that the dose-response relationship involves numerous factors, such as the pollen’s allergenicity, individual sensitivity, etc.;
  3. Climate change may influence pollinisation starting dates in a number of plant species, prompting it to start earlier and therefore prolonging the pollinisation period.

Analysis of the risks linked to the A.

trifida and A. psilostachya ragweed species

In 2014, the European Parliament and European Council published a regulation on the prevention and management of the introduction and propagation of exotic invasive species. This regulation contains a list of species for which coordinated prevention and control actions should be implemented between the member States of the European Union. These actions purpose to reduce the negative impact of these species on biodiversity, pollination, the regulation of waterways, etc., as well as other possible negative effects including allergies.

In order to add a species to this list of invasive species in the European regulation, the European Commission must obtain an analysis of its risk.

And so ANSES has conducted a risk analysis for the two ragweed species, A. trifida and A. psilostachya.

The risks linked A. trifida are extremely diverse from those of A. psilostachya. The ecological and biological characteristics of A. psilostachya and the fact that it has been present in Europe for fairly some time in an area that has remained highly circumscribed leads us to conclude that the risk of invasion by this species and the risk of it being reintroduced in the current state of international trade is relatively low.

In contrast, the risks linked to A.

trifida are much higher. Introduction from the area of origin is hard to control. Numerous eco-climatic zones favourable to the species are found throughout Europe in areas where cropping systems own developed which could facilitate the species’ development. Due to the grand difficulty of fighting A. trifida in non-agricultural environments and the allergenicity of its pollen, it is a proven threat to human health and to the environment.

Pollen and mold counts

Pollen and mold counts measure the quantity of airborne allergens present in the air.

Counts are compiled by a variety of methods. Pollen and mold spore counts can be sure daily, and are reported as grains per cubic meter of air. Certified aeroallergen counters at numerous universities, medical centers and clinics provide these counts on a volunteer basis.

The National Allergy BureauT (NABT) is the nation’s only pollen and mold counting network certified by the AAAAI. As a free service to the public, the NAB compiles pollen and mold counts from certified stations across the nation and reports them to the media three times each week.

These counts are also available on the NAB sheet of the AAAAI’s Web site, www.aaaai.org.

Interpretation of pollen and mold counts and their relationship to symptoms is complicated. Sampling techniques such as the type of device used and its location within the community can affect counts. While numerous patients develop symptoms when pollen counts are 20-100 grains per cubic meter, one’s symptoms may also be affected by recent exposure to other allergens, the intensity of pollen exposure, and individual sensitivity.

Pollen counts reported to the public are generally taken the preceding one to three days, and may vary widely from day to day during a season. Overall, the use of pollen counts in predicting symptom severity in a given individual is somewhat limited.

What is the difference between allergies and a cold?

Cold and allergy symptoms are generally extremely similar, but the main difference is the length of time that symptoms final.

A freezing normally disappears after a week. Allergies, on the other hand, can final for weeks or even longer. The following chart provides a few guidelines to assist you differentiate between a common freezing and allergies.

Can Allergies be Controlled?

Avoidance is the best defense against allergies. At your first appointment we will be discussing methods you can use into your home to lessen the allergen in your environment. If you are unable to avoid the allergen, medications may be taken to relieve symptoms. Medications may assist relieve symptoms, but they do not alter the allergy immune response.

If symptoms cannot be controlled, allergy shots may be prescribed. Often people take allergy shots because they don’t desire to take medications every day. Allergy shots can put your allergies into remission. Read more about allergy shots on our website.

Tips to Remember are created by the Immunotherapy Committee of the American Academy of Allergy, Asthma and Immunology.

Role of the patient — communication

To ensure optimal care, patients with allergies and asthma must take an athletic role in their treatment by asking questions, learning about triggers of their condition, and understanding reasons for various methods of treatment.

Open communication is a necessary, successful part of allergic disease management. As a patient, you may desire to enquire these questions:

* Is the physician who is treating me or my family specifically trained to make an appropriate diagnosis and provide effective management and treatment of allergic disease?
* Has my physician completed a fellowship in allergy and immunology?
* Does my physician regularly attend continuing medical education programs in allergy and immunology?
* What does the diagnosis and treatment of my allergies and/or asthma entail? What are my options? Do my symptoms meet insurance guidelines for allergy referral?
* Has the diagnosis and treatment plan my physician prescribed been proven effective by virtue of accepted standards for scientific evaluation?

You and your allergist/immunologist can work together so that you can make appropriate changes in your environment and take medications as prescribed.

With appropriate diagnosis and effective management of your allergic disease, you should be capable to experience the optimal quality of life that you deserve.
Your allergist/immunologist can provide you with more information on the management and treatment of allergic disease.
The content of this brochure is for informational purposes only. It is not intended to replace evaluation by a physician.

What part of ragweed pollen causes human allergies

If you own questions or medical concerns, please contact your allergist/immunologist.

American Academy of Allergy,
Asthma and Immunology
555 East Wells Highway, Suite 1100
Milwaukee, WI 53202

AAAAI Web sitewww.aaaai.org



keep windows closed at night to prevent pollens or molds from drifting into your home. Instead, if needed, use air conditioning, which cleans, cools, and dries the air.
minimize early morning activity when pollen is generally emitted-between 5-10 a.m.
keep your car windows closed when traveling.
try to stay indoors when the pollen count or humidity is reported to be high, and on windy days when dust and pollen are blown about.
take a vacation during the height of the pollen season to a more pollen-free area, such as the beach or sea.
take medications prescribed by your allergist/immunologist regularly, in the recommended dosage.

Effects of weather and location

Weather can influence hay fever symptoms.

Allergy symptoms are often minimal on days that are rainy, cloudy or windless, because pollen does not move about during these conditions. Boiling, dry and windy weather signals greater pollen and mold distribution and thus, increased allergy symptoms.

If you are allergic to plants in your area, you may believe that moving to another area of the country with diverse plants will assist to lessen your symptoms. However, numerous pollens (especially grasses) and molds are common to most plant zones in the United States.

Additionally, other related plants can also trigger the same symptoms. Numerous who move to a new region to escape their allergies discover that they acquire allergies to new airborne allergens prevalent in their area within one to two years. Therefore, moving to another part of the country to escape allergies is often ultimately disappointing, and not recommended.

Appropriate treatment-not escape-is the best method for coping with your allergies. If your seasonal allergy symptoms are making you miserable, see your allergist/immunologist, who will take a thorough history and conduct tests, if needed, to determine exactly which pollens or molds are triggering your symptoms.

What part of ragweed pollen causes human allergies

He or she will assist you determine when these airborne allergens are most prevalent in your area. To lessen your symptoms, your allergist/immunologist may also prescribe an allergy nose spray, non-sedating antihistamine, decongestant or other medications.

If your symptoms continue or if you own them for numerous months of the year, your allergist may also recommend immunotherapy treatment, also called allergy vaccinations or shots.

This treatment involves receiving injections periodically-as sure by your allergist/immunologist-over a period of three to five years. This treatment helps your immune system to become more and more resistant to the specific allergen, and lessens your symptoms as well as the need for future medications.

Colds vs. Allergies

Many people may not realize they own allergies, often attributing their congestion and runny nose to a freezing. Left untreated, allergies can cause more serious conditions love sinusitis or ear infections.

It is significant to decipher between allergies and colds.​

Allergies Colds
Symptoms Runny or stuffy nose, sneezing, wheezing, watery and itchy eyes. Can include fever and aches and pains along with allergy symptoms.
Warning Time Symptoms start almost immediately after exposure to allergen(s). Usually takes a few days to hit full force.
Duration Symptoms final as endless as you are exposed to the allergen and beyond, until the reaction triggered by the allergen ends.

If the allergen is present year-round, symptoms may be chronic.

Symptoms should clear up within several days to a week.

Main allergenic pollens

All pollens do not provoke allergies. To cause allergy symptoms, it is essential that the pollen grains reach to the respiratory mucosa of human being. Only plants anemophilous disseminate pollen grains by the wind, while entomophilous plants require the intervention of an insect to ensure fertilization by transferring pollen from the male to female flower receiver.
The pollens of high allergenicity are produced by anemophilous plants (trees and grasses).
To be allergenic, pollen grain must contain substances (proteins or glycoproteins) immunologically recognized as harmful to an individual.

The allergy potency of a plant species is the ability of its pollen to provoke an allergy for a part of the population.
Allergy potency can be:
— feeble or null (species which can be planted in urban areas)
— Moderate (only a few trees or herbaceous of these species can be planted in urban areas)
— Strong (species which can not be planted in urban areas)

Outdoor allergens

Seasonal allergic rhinitis, often referred to as «hay fever,» affects more than 35 million people in the United States.

These seasonal allergies are caused by substances called allergens. Airborne pollens and mold spores are outdoor allergens that commonly trigger symptoms during the spring and drop. During these times, seasonal allergic rhinitis sufferers experience increased symptoms-sneezing, congestion, a runny nose, and itchiness in the nose, roof of the mouth, throat, eyes and ears-depending on where they live in the country and the exact allergen to which they are allergic.


Molds are microscopic fungi-related to mushrooms-but without stems, roots or leaves.

Their spores float in the air love pollen, and are present throughout the year in numerous states. Unlike pollens, molds do not own a specific season, but are affected by weather conditions such as wind, rain or temperature. Outdoor mold spores start to appear after a spring thaw and reach their peak in July in warmer states and October in the colder states. Molds can be found every year endless outdoors in the South and on the West coast.

Common airborne molds include alternaria, cladosporium and aspergillus. Molds are present in almost every possible habitat. Outdoors, they can be found in soil, vegetation and rotting wood. Molds can also be found indoors in attics, basements, bathrooms, refrigerators and other food storage areas, trash containers, carpets and upholstery.

Dos and Don’ts

Following are someDosandDon’tsthat you may desire to follow during the pollen and mold seasons to lessen your exposure to the pollens or molds that trigger your allergy symptoms.

Role of the allergist — management and treatment

An allergist/immunologist is a physician specially trained to manage and treat allergies and asthma.

Becoming an allergist/immunologist requires completion of at least nine years of training. After completing medical school and graduating with a medical degree, a physician will then undergo three years of training in internal medicine (to become an internist) or pediatrics (to become a pediatrician).

What part of ragweed pollen causes human allergies

Once physicians own finished training in one of these specialties, they must pass the exam of either the American Board of Pediatrics (ABP) or the American Board of Internal Medicine (ABIM). Internists or pediatricians who wish to focus on the subspecialty of allergy/immunology then finish at least an additional two years of study, called a fellowship, in an allergy/immunology training program. Allergist/immunologists who are listed as ABAI-certified own successfully passed the certifying examination of the American Board of Allergy and Immunology (ABAI), following their fellowship.
As a result of this extensive study and training, an allergist/immunologist is the best-qualified medical professional to effectively manage the comprehensive needs of patients with allergic disease.

Allergist/immunologists are trained in the prevention, diagnosis, and treatment of immune system problems such as allergies, asthma, inherited immunodeficiency diseases, autoimmune diseases and even AIDS. Unlike a freezing, allergic disease is not a condition that someone can just «get over.» The assist of a trained allergist/immunologist can reduce how often patients need to stay home from work or school due to symptoms. Studies show that those under the care of an allergist/immunologist also make fewer visits to emergency rooms, and are better capable to daily manage their allergies and asthma.
If you are enrolled in a managed care organization, your insurer will own a specific set of guidelines that assist your primary care physician decide when to refer you to an allergist/immunologist.

Once you are referred, the allergist/immunologist will work to accurately diagnose your condition by taking a thorough patient history, including information about your symptoms, family history, and home and work environments. Your allergist/immunologist will also conduct allergy skin testing and any other needed tests. Combining specific information from your history and tests, the allergist/immunologist will be capable to make an precise diagnosis. To assist prevent symptoms, he or she will work with you to develop an appropriate management plan and will prescribe the most cost-effective treatment, including recommendations for specific medications and/or devices, and any needed environmental control measures.

Your allergist/immunologist and allied health staff will not only prescribe medications and devices, but will also show you how and when to use them.

Common allergic diseases include:

*Allergic rhinitis, or «hay fever.» In the United States, approximately 35 million people suffer from this disease, which is characterized by sneezing, congestion, itching and dripping of the nose, and itchy, watery eyes.
*Asthma, a chronic lung disease characterized by coughing, chest tightness, shortness of breath and wheezing. Asthma affects more than 17 million Americans, and asthma cases appear to be increasing annually.

Asthma symptoms may be triggered by allergens or other, non-allergic stimuli, such as respiratory tract infections, freezing air or tobacco smoke.
*Sinusitisand otitis media, common allergic diseases often triggered by allergic rhinitis. Sinusitis is an inflammation of the nasal sinuses, which are hollow cavities within the cheek bones found around the eyes and behind the nose. This condition affects over 15% of the U.S. population. Otitis media — or common ear infections — is the most common childhood disease requiring physician care.
*Atopic dermatitis, also called eczema.

Symptoms of this allergic skin condition include itching, reddening, and flaking or peeling of the skin. This rash is generally seen in young infants, but can happen later in individuals with personal or family histories of atopy, meaning asthma or allergic rhinitis.
*Urticaria, also known as hives, and angioedema. Hives are itchy, red bumps that appear on the surface of the skin. They can happen in clumps and range in size, and can be either chronic — appearing and disappearing for no reason — or acute.

Triggers of acute hives include infection or ingestion of some foods or medications. Often appearing with hives, angioedema is a non-itchy swelling in the deeper layers of the skin.
*Anaphylaxis, a severe, systemic allergic reaction generally caused by substances that are injected or ingested (eaten), including some foods and medications, insect stings and latex. Symptoms can include a feeling of warmth, flushing, tingling in the mouth, a red, itchy rash, feelings of light-headedness, shortness of breath, severe sneezing, anxiety, stomach or uterine cramps, and/or vomiting and diarrhea. In severe cases, a drop in blood pressure results in a loss of consciousness and shock.

Without immediate treatment — an injection of epinephrine (adrenalin) and expert care — anaphylaxis can be fatal.

On this sheet you will discover information on:

Allergic disease, Allergy Testing,Stinging Insect Allergy,Latex and
Skin allergies.


take more medication than recommended in an attempt to lessen your symptoms.
mow lawns or be around freshly cut grass; mowing stirs up pollens and molds.
rake leaves, as this also stirs up molds.
hang sheets or clothing out to dry.

Pollens and molds may collect in them.
grow too numerous, or overwater, indoor plants if you are allergic to mold. Wet soil encourages mold growth.

Tips to Remember are created by the Public Education Committee of the American Academy of Allergy, Asthma and Immunology.

Comparative table of the diverse plants according to there allergy potency

Species Family Allergy potency
Maple* Aceraceae Moderate
Alder* Betulaceae High
Birch* High
Hornbeam* High
Hop-Hornbeam Low/Null
Hazel* High
Eastern Baccharis Composate Moderate
Cade Cupressaceae High
Mediterranean Cypress High
Arizona Cypress High
Juniper Low/Null
Whitecedar* Low/Null
False Acacia* Fabaceae Low/Null
Chestnut* Fagaceae Low/Null
Beech* Moerate
Oak* Moderate
Walnut* Juglandaceae Low/Null
Paper Mulberry* Moraceae High
White Mulberry* Low/Null
Ash* Oleaceae High
Olive High
Privet* Moderate
Pine* Pinaceae Low/Null
Plane** Platanaceae Moderate**
Poplar* Salicaceae Low/Null
Willow* Moderate
Yew* Taxaceae Low/Null
Japanese Red Cedar Taxodiaceae High
Lime* Tilliaceae Moderate
Elm* Ulmaceae Low/Null

*several species
** plane pollen is has a low allergy potency.

But, microneedles contained in the linters coming from the degradation of female capitulums of the previous year are extremely irritative.

Spontaneous Herbaceous
Species Family Allergy potency
Gosefoot* Chenopodiaceae Moderate
(Salsola kali)
Ragweed* Composate High
Mugwort* High
Oxeye daisy* Low/Null
Dandelion* Low/Null
Mercuries* Euphorbiaceae Moderate
Plantain* Plantaginaceae Moderate
Grasse Poaceae high
Sorrel* (Rumex) Polygonaceae Moderate
Nettle* Urticaceae Low/Null
Pellitory High
*several species
Ornamental Grasses
Species Family Allergy potency
Reed canary grass Poaceae High
Reed grass Moderate
Tufted hairgrass High
Sand Ryegrass Moderate
Fescue* High
Oatgrass High
Hare's tail Moderate
Giant feather grass Moderate
*several species

Genus of plants

«Hymenoclea» redirects here.

For the genus of moth, see Hymenoclea (moth).

For other uses, see Ragweed (disambiguation).

Ragweeds are flowering plants in the genus Ambrosia in the aster family, Asteraceae. They are distributed in the tropical and subtropical regions of the Americas, especially North America,[2] where the origin and middle of diversity of the genus are in the southwestern United States and northwestern Mexico.[3] Several species own been introduced to the Ancient World and some own naturalized and own become invasive species.[2] Ragweed species are expected to continue spreading across Europe in the near future in response to ongoing climate change.[4]

Other common names include bursages[5] and burrobrushes.[6] The genus name is from the Greekambrosia, meaning «food or drink of immortality».[2]

Ragweed pollen is notorious for causing allergic reactions in humans, specifically allergic rhinitis.

Up to half of every cases of pollen-related allergic rhinitis in North America are caused by ragweeds.[7]

The most widespread species of the genus in North America is Ambrosia artemisiifolia.

Pollen count

How do scientists know how much pollen is in the air? They set a trap. The trap — generally a glass plate or rod coated with adhesive — is analyzed every few hours, and the number of particles collected is then averaged to reflect the particles that would pass through the area in any 24-hour period. That measurement is converted to pollen per cubic meter.

Mold counts work much the same way.

A pollen count is an imprecise measurement, scientists confess, and an arduous one — at the analysis stage, pollen grains are counted one by one under a microscope. It is also highly time-consuming to discern between types of pollen, so they are generally bundled into one variable. Given the imprecise nature of the measurement, entire daily pollen counts are often reported simply as low, moderate or high.

The American Academy of Allergy, Asthma & Immunology provides up-to-date pollen counts for U.S.



The symptoms of allergic rhinitis may at first feel love those of a freezing. But unlike a freezing that may incubate before causing discomfort, symptoms of allergies generally appear almost as soon as a person encounters an allergen, such as pollen or mold.

Symptoms include itchy eyes, ears, nose or throat, sneezing, irritability, nasal congestion and hoarseness.

People may also experience cough, postnasal drip, sinus pressure or headaches, decreased sense of smell, snoring, sleep apnea, fatigue and asthma, Josephson said. [Oral Allergy Syndrome: 6 Ways to Avoid an Itchy, Tingling Mouth]

Many of these symptoms are the immune system’s overreaction as it attempts to protect the vital and sensitive respiratory system from exterior invaders. The antibodies produced by the body hold the foreign invaders out, but also cause the symptoms characteristic of allergic responses.

People can develop hay fever at any age, but most people are diagnosed with the disorder in childhood or early adulthood, according to the Mayo Clinic.

Symptoms typically become less severe as people age.

Often, children may first experience food allergies and eczema, or itchy skin, before developing hay fever, Josephson said. «This then worsens over the years, and patients then develop allergies to indoor allergens love dust and animals, or seasonal rhinitis, love ragweed, grass pollen, molds and tree pollen.»

Hay fever can also lead to other medical conditions. People who are allergic to weeds are more likely to get other allergies and develop asthma as they age, Josephson said. But those who get immunotherapy, such as allergy shots that assist people’s bodies get used to allergens, are less likely to develop asthma, he said.

Tests & diagnosis

A physician will consider patient history and act out a thorough physical examination if a person reports having hay-fever-like symptoms.

If necessary, the physician will do an allergy test. According to the Mayo Clinic, people can get a skin-prick test, in which doctors prick the skin on a person’s arm or upper back with diverse substances to see if any cause an allergic reaction, such as a raised bump called a hive. [7 Strange Signs You’re Having an Allergic Reaction]

Blood tests for allergies are also available. This test rates the immune system’s response to a specific allergen by measuring the quantity of allergy-causing antibodies in the bloodstream, according to the Mayo Clinic.

Common allergens

The most common allergen is pollen, a powder released by trees, grasses and weeds that fertilize the seeds of neighboring plants.

As plants rely on the wind to do the work for them, the pollination season sees billions of microscopic particles fill the air, and some of them finish up in people’s noses and mouths.

Spring bloomers include ash, birch, cedar, elm and maple trees, plus numerous species of grass. Weeds pollinate in the tardy summer and drop, with ragweed being the most volatile.

The pollen that sits on brightly colored flowers is rarely responsible for hay fever because it is heavier and falls to the ground rather than becoming airborne. Bees and other insects carry flower pollen from one flower to the next without ever bothering human noses.

Mold allergies are diverse.

Mold is a spore that grows on rotting logs, dead leaves and grasses. While dry-weather mold species exist, numerous types of mold thrive in moist, rainy conditions, and release their spores overnight. During both the spring and drop allergy seasons, pollen is released mainly in the morning hours and travels best on dry, warm and breezy days.

Hay fever treatments

Dr. Sarita Patil, an allergist with Massachusetts General Hospital’s Allergy Associates in Boston, talked to Live Science about strategies for outdoor lovers with seasonal allergies.

Patil suggested figuring out exactly what type of pollen you’re allergic to, and then avoiding planning outdoor activities during peak pollinating times in the months when those plants are in bloom.

Numerous grasses, for example, typically pollinate in tardy spring and early summer and release most of their spores in the afternoon and early evening.

Her other strategies: Be capable to identify the pollen perpetrator by sight; monitor pollen counts before scheduling outdoor time; go exterior at a time of day when the plants that make you go achoo are not pollinating; and wear protective gear love sunglasses, among other tips. [7 Strategies for Outdoor Lovers with Seasonal Allergies]

Allergy sufferers may also select to combat symptoms with medication designed to shut below or trick the immune sensitivity in the body.

Whether over-the-counter or prescription, most allergy pills work by releasing chemicals into the body that bind naturally to histamine — the protein that reacts to the allergen and causes an immune response — negating the protein’s effect.

Other allergy remedies attack the symptoms at the source. Nasal sprays contain athletic ingredients that decongest by soothing irritated blood vessels in the nose, while eye drops both moisturize and reduce inflammation. Doctors may also prescribe allergy shots, Josephson said.

For kids, allergy medications are tricky.

A 2017 nationally representative poll of parents with kids between ages 6 and 12 found that 21% of parents said they had trouble figuring out the correct dose of allergy meds for their child; 15% of parents gave a kid an adult form of the allergy medicine, and 33% of these parents also gave their kid the adult dose of that medicine.

Doctors may also recommend allergy shots, a neti pot that can rinse the sinuses, or a Grossan Hydropulse — an irrigating system that cleans the nose of pollens, infection and environmental irritants, Josephson said.

Alternative and holistic options, along with acupuncture, may also assist people with hay fever, Josephson said.

People can also avoid pollen by keeping their windows closed in the spring, and by using air purifiers and air conditioners at home.

Probiotics may also be helpful in stopping those itchy eyes and runny noses. A 2015 review published in the journal International Forum of Allergy and Rhinology found that people who suffer from hay fever may benefit from using probiotics, or «good bacteria,» thought to promote a healthy gut. Although the jury is still out on whether probiotics are an effective treatment for seasonal allergies, the researchers noted that these gut bacteria could hold the body’s immune system from flaring up in response to allergens — something that could reduce allergy symptoms.

[5 Myths About Probiotics]

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This article was updated on April 30, 2019, by Live Science Contributor Rachel Ross.

Updated on 16/07/2018