Pollens and Autumn allergies

Mon, 10/06/2014 - 14:45
Pollens and Autumn allergies

The appearance of crocus in the fields marks the end of summer. Students start returning to school, and the worst is over for people allergic to grass. The hay is cut. However, some people continue to have hay fever symptoms into the fall. They are sensitive to herbaceous plant pollen.

Allergy-causing plants and pollens in the fall

Allergy-causing pollens are light, locally abundant and carried by the wind: they are anemophilous. In contrast, entomophilous plants are pollinated by insects. More attractive, these plants rarely cause allergies. Even the crocus mentioned at the beginning does not cause allergies: it is a hermaphrodite!

 Herbaceous plants are a heterogeneous family and include plants with high sensitizing ability.  They are also called weeds, and their peak pollen production occurs between August and October, depending on the region and species.

Some useful information on the main plants:

Pollens and Autumn allergies

The plantain flower

The ribwort plantain (plantago lanceolata) is a weed that grows in fields or in grass. It is said that their leaves are shaped like spearheads or hares' ears. Its role in allergy symptoms is hidden by that of grass.

 

Pollens and Autumn allergies

Parietaria

The lichwort, or Parietaria, is part of the nettle family; its red stalks spread and hang on the ancient walls of the Midi canal. This plant causes many severe allergic reactions during its pollination period, since it coincides with the period when vacationers are traveling

 

Pollens and Autumn allergies

Mugwort in bloom

Mugwort, or Artemisia,  has many species and gets its name from the moon goddess Artemis, who, according to legend, was the first to discover it. Mugwort or artemisia vulgaris is the most common herbeaceous plant in the Northern Hemisphere. Its pollination period lasts for 4 to 6 weeks, and each milligram of mugwort contains approximately 160,000 pollen grains! This plant prefers nitrate-rich soils, open areas, rubble and the sides of roads. According to popular belief, mugwort has the power of quickening women's menstruation and helping with childbirth... Desired and sometimes cultivated are aromatic mugworts: genepi, which is gathered at an altitude of 3000 m, is part of the secret recipe behind the Chartreuse liqeur; tarragon is used in cooking poultry and yields the Choron sauce; absinthe is more toxic than allergy-causing...

 

Pollens and Autumn allergies

Common ragweed

Common ragweed, or Ambrosia artemisiifolia, is a plant that comes from North America. It is invasive species and has taken over the Rhône valley. This undemanding plant immediately invades all abandoned areas, growing in paths bulldozers leave behind.  Not only is it currently found in the Lyon region, but it has spread to both rural and urban settings.

This plant is a significant public health problem which parliamentarians are studying (cf. map below; dark colors represent the areas where the problem is very significant)

 

2011 Ragweed map
contact@parlementaires-ambroisie.fr

Clinical symptoms of autumn allergies

 

Symptoms may appear at any moment. Although they are most likely to appear during a stroll in the countryside, they may also occur in the city and at home, often taking the form of the common cold.

Rhinitis: all symptoms of allergic rhinitis are grouped together under the name PAREO in French, which evokes the holidays:

    P: Pruritus: the nose itches
    A: Anosmia: loss of smell. It is rare in children and is a disability among adults; it is a sign of a very strong allergy
    R: rhinorrhea: the nose is runny; children sniff
    E: sneezing, often repeated and in volleys
    O: obstruction: the nose is blocked; often this is the symptom hardest to treat

Conjunctivitis: It accompanies rhinitis. Often, allergic rhino-conjunctivitis is also mentioned. The affected child will complain of itching, it stinging, and discomfort. The child feels as if there is sand beneath the eyelids.  Conjunctivitis develops according to the weather; it improves (as with other symptoms) with rain. The child's condition further improves when the child wears tinted glasses whenever he or she goes out.

Coughing : Minor coughing caused by allergies and associated with rhino-conjunctivitis may also be present. However, vigilance must be exercised if the fits are nocturnal; efforts must be made when crossing an abandoned area.  The cough might be spasmodic, an asthmatic cough.  All coughing children might be carrying pollen and must undergo pulmonary function testing (PFT) to diagnose asthma

Asthma: signs of coughing, wheezing and respiratory difficulties. The nose guards against allergic aggressors: it defends the system, obstructs the allergen. The nose begins to run since it blocks pollens from entering.  Sometimes it is overwhelmed, especially in children with antecedents of bronchiolitis or recurring coughing. The initial cold is complicated by mucosa and bronchial tree inflammations. The allergen sets off an asthma attack. This is where the expression "ça lui est tombé sur les bronches [it spread to the bronchi]" comes from.

In the fall, people allergic to grass during spring experience the same symptoms: hay fever

 

Traps in clinical interpretation of autumn allergies

As we stated earlier, September marks the beginning of the school year. It is also marks the start of the season for common cold and lower respiratory infections. Allergy and infection symptoms are similar.  Both allergies and infections cause inflammation: a blocked nose, coughing and breathing difficulties. We have observed the diagnosis of roaming ragweed-induced allergies in children.  Remember that

 

Fever is not a symptom of an allergy. Rather, it may appear at the early stage of infection.
In allergic rhinitis, sneezing occurs in volleys, and the eyes experience frequent tingling. histamine">Antihistamines significantly decrease the intensity of such discomfort.
Since the pollination of herbaceous plants ends in late October, the symptoms should be gone.  
You can easily track pollination peaks through the RNSA's [national aerobiology monitoring network] pollenic bulletin: www.pollens.fr  

In September, as nights become cooler, people remain in their apartments and close their windows, while the central heating system is sometimes turned on at the end of the month. At the same time, dust mites begin reproducing...
If in doubt about the causes, talk to an allergist. The skin-prick testing is a 15-minute painless process that provides valuable predictions.  

Pollens and Autumn allergies

Skin-prick testing

Autumn pollen and cross allergies

To understand cross allergies, we will use an example from below:

  • The allergist noticed that, over a long period of time, all his patients allergic to birch sneezed frequently in March. However, some of these patients experienced tingling in the mouth when they bit into an apple; sometimes, dizziness or hives followed.
  • The botanist does not see any connection between the birch fruit and pollen. We are very clear on this as well
  • The biologist found consensus: there was a structural connection (proteins resembled one another without being identical) between a birch allergen (named Betv1) and an apple allergen (Mald1). The patient's immune system takes note of this resemblance and fights both the fruit and pollen allergens, causing patient discomfort...

Since then, many publications have described and classified these cross allergies. We now know that patients allergic to pollen have three times as many food allergies as others; these allergies specifically involve fruits and vegetables.
The main types of cross allergies involving herbaceous plant pollens documented in scientific literature are the following:

  • Mugwort pollen and dill, carrots, caraway celery, cilantro, fennel, parsley
  • Common ragweed and banana, cantaloup, watermelon, lychee
  • Plantain pollen and cantaloup

These are the most common combinations; however, these combinations are not always found in the same individual. Some studies have shown that up to 50% of individuals allergic to mugwort pollen are sensitive to celery (tested positive)
Symptoms of the oral syndrome due to ingesting cross-allergy inducing foods include itchy lips and mouth, sometimes swelling of the lips and even of the throat. Simple anti-allergy treatments (histamine">antihistamines) are required to treat these symptoms. If a significant amount of the allergen has been ingested or the patient is known to be asthmatic, the reactions may be quick and violent, ranging from an acute severe asthma attack, widespread hives with mucosal edema (also called Quincke's edema) to life-threatening phylactic shock">anaphylactic shock. Adrenalin treatment is required. A child or an adult allergic to mugwort/celery must always carry some adrenalin with them.

 

Treatment advice

Avoid overexposure to pollen

The best way of treating all allergies is allergen eviction, but it is impossible to eliminate all pollens. However, overexposure still may be reduced:

  • The little boy from the Rhône-Alpes will delay returning from his vacation at Grandma's for as long as he can!
  • Caution should be exercised during hot and sunny days; picnics should be avoided, and rooms should only be aired at night.
  • The windows should be up when driving; they function as pollen filters
  • If possible, head south to the sea for the holidays. If not, the local pool is a good alternative for windy days and for when pollen production reaches its peak (pollen sticks to the water's surface)

Relieve symptoms

Orally-administered histamine">antihistamines (or H1-histamine">antihistamines) comprise basic treatment. Currently, they are used as daily preventive treatment; their dosage can be doubled (in the morning and evening) if the patient's situation worsens.
They are complemented by local treatment:

  • histamine">Antihistamine or anti-degranulating eye drops. Children may use hydrocortisone eye drops for treating allergic conjunctivitis only with a strict prescription from a specialist
  • Corticosteroid nasal sprays may be used if H1-histamine">antihistamines alone do not facilitate nasal decongestion.  They may be used on children.

Treating the disorder

Hyposensibilization is the only available allergy-specific treatment.  This treatment is sublingually administered (the drops are placed below the tongue) before the allergy season starts (i.e. before pollen season). The hyposensibilization treatment lasts a minimum of 3 years. Significant improvements are observed in the first year of treatment.
This treatment seeks to induce progressive tolerance to pollens in the environment.

Tools for at-risk patients with allergies

The first-aid kit for children with pollen allergies must include adrenalin if:

  • the child has persistent asthma and food allergies
  • the child has a disorder that combines herbaceous plant-induced rhinoconjunctivitis and a food allergy to celery, spices or cantaloup.

Pollens and Autumn allergies

 ANAPEN® :  Children weighing between 15kg to 30 kg, 0.15 mg, yellow pen                                                          

  Children weighing more than 30 kg, 0.30 mg, green pen

Remember this when injecting into the thigh: "I remove all that is black and I press on the red for 10 seconds"

After the herbaceous plants

October draws out, and autumn's colors adorn the landscape; the plants become dormant and their reproduction will wait until the new year. The last tree to release a large quantity of pollen is the Lebanon cedar. It releases a shower of heavy, non-allergy causing pollen on car hoods. When "all the leaves are falling down, orange, yellow, red and brown," the patient allergic to ragweed starts to breathe and sleep better. As an allergist, I can say that the blooms return after the snowflakes of Christmas; in February, the hazelnut tree coats its catkins with golden pollen before leaving them for the wind to disperse. Thus, the species' next generation is ensured.

Pollens and Autumn allergies

Pediatric allergist
Therapeutic education consultant for atopic dermatitis