Seasonal Allergies

The Changes of Season – Herbs for Seasonal Allergies

Posted: August 2023

Author: Phil Rasmussen | M.Pharm., M.P.S., Dip. Herb. Med.; M.N.I.M.H.(UK), F.N.Z.A.M.H.

While allergic rhinitis is most often seen in springtime, it is not exclusively a springtime condition. As the seasons move into autumn then winter, our body’s also go through a significant adjustment period. During these changes, our immune systems, and physiological responses to the change in temperature and environment, can sometimes become dysregulated. Allergic rhinitis involves inflammation of the mucous membranes of the nasal passages, congestion of the nasal passages, watery nasal discharge, and a post-nasal drip.

It is observed to affect around one in five New Zealanders, and has a significant health burden, sometimes being associated with serious comorbidities including asthma, sinusitis, and conjunctivitis. Mast cells and basophils play a role in mediating the inflammatory responses by the immune system, leading to allergic rhinitis, sinusitis, and asthma. Binding of the allergen to IgE antibodies on the surface of basophils and mast cells induces these cells to undergo degranulation, which releases histamine and other inflammatory cytokines into the blood stream. This leads to vasodilation, increased vascular permeability, further recruitment of inflammatory cells, and an adaptive immune response.

With greater numbers of people travelling from one part of the world to another, and sometimes several times a year, the impact of these types of naso-respiratory conditions, can be significant. Patients with allergic rhinitis or a related condition can present between April and May in Aotearoa, New Zealand after their recent arrival from the northern hemisphere where spring is in full bloom. It is common with the sudden change in climate and exposure to new allergens challenging their immune systems.

Additionally, the pollen map of many countries including Aotearoa New Zealand is changing as plants and their habitats change through human practices such as plantation forestry and monoculture-based horticulture. A recent research programme in Auckland, which is monitoring pollen counts and types for the first time in many years, has obtained data suggesting the pollen season has extended by 75%, compared to its length in 1988.¹ Climate change is suspected as being a key reason for this extended pollen season.

Apart from seasonal rhinitis, related conditions such as asthma can also become more prevalent in autumn, particularly in children. ^{2, 3} Rates vary considerably from one geographical region to another though, suggesting the importance of environmental and seasonal allergens.

Dietary recommendations

A healthy diet with plenty of plant-based, flavonoid-rich foods and nutrients such as zinc and vitamins A and C, helps promote a healthy immune system. Fruits and vegetables are high in flavonoids, and many flavonoids including quercetin have been shown to have anti-allergic and anti-inflammatory activities. These actions include an ability to inhibit mast cell histamine release, as well as support a healthy gut microbiome. The increased prevalence of allergic rhinitis and asthma in recent decades, may also be related to lower intakes of organic fruits and vegetables and an increased intake of highly processed foods, causing decreased levels of antioxidant nutrients and fatty acids.

Avoiding so-called mucus-producing foods, such as excess gluten, wheat, dairy products, and processed foods, is also recommended where seasonal allergies are problematic. Including plenty of ginger or Alliaceae family vegetables such as onions, leeks, and garlic in the diet, and adding nasturtium, rocket, onionweed or rocket to the dinner plate, can also help reduce mucous membrane inflammation and catarrh production.

Some useful phytomedicines

Baical skullcap (Scutellaria baicalensis) is widely used in Chinese medicine to treat both acute and chronic inflammatory conditions. Indications for its use include allergic conditions such as asthma, eczema, and allergic rhinitis. It exhibits many anti-inflammatory, anti-allergic and immune-modulating effects, and baicalein, wogonin and an ethanol extract of Baical skullcap have been shown to alleviate allergic airway inflammation and to suppress mast cell degranulation and histamine release.⁴

Rehmannia (Rehmannia glutinosa) is another medicinal plant used in traditional Chinese medicine to treat allergies and autoimmune conditions. As part of a treatment formula, or in 10-20mL doses as a simple (by itself), it can produce both symptom relief as well as longer term immune modulation. It is also a key component of traditional Chinese formulations used for centuries to treat allergic asthma and shown to inhibit the infiltration of inflammatory cells into the airways and airway remodelling.⁵

While often regarded simply as an immune stimulant, alkylamide-rich root extracts of both Echinacea purpurea, and Echinacea angustifolia, have significant anti-inflammatory and immunomodulatory properties. Included in their complex influences on our immune systems, are anti-allergic properties, as shown by inhibitory effects on mast cell degranulation and calcium influx by an extract of Echinacea purpurea as well as isolated alkylamides.⁶ These and their wide ranging anti-inflammatory actions, complement the immune surveillance actions of good quality Echinacea preparations, thus enhancing resistance to a wide range of potentially infectious bacteria, viruses and other disease-producing microorganisms which can become problematic with the change of season.

Anti-Catarrhal phytomedicines

Several herbs have a gentle but significant decongestant action when consumed orally and can provide useful symptomatic relief in the management of allergic rhinitis or sinusitis. These are much safer for long term use, than drug-based decongestants such as xylometazoline or pseudoephedrine.

Elderflower (Sambucus nigra) is of course a classical remedy here, whose traditional applications include for the common cold and influenza, allergic rhinitis, sinusitis, nasal and sinus congestion. It is rich in anti-inflammatory flavonoids including rutin, quercetin, and phenolic acids.

Eyebright (Euphrasia officinalis) is another European plant which has traditionally been used for both eye conditions including inflammation and redness, as well as for seasonal allergies. Taken internally, eyebright has a useful astringent and tonifying effect on the mucous membranes and can thus help to reduce the over-secretion of mucus from the upper respiratory tract.

Ribwort (Plantago lanceolata) is an ideal tonic for the mucous membranes as it has astringent, anti-inflammatory and anti-catarrhal properties.⁷ While overall it is a relatively gentle and nourishing herb, it can work remarkably well for seasonal naso-respiratory tract conditions, when taken regularly and in reasonable doses. As a relatively pleasant tasting and mucilage containing extract, it is also particularly useful for treating upper respiratory tract conditions in children.

New Zealand grown Horseradish (Armoracia rusticana) root can also be a powerful and pungent warming herb to include in an autumn tonic. It is especially useful where protection against infectious or inflammatory conditions of the upper respiratory tract is wanted. Antimicrobial actions are prominent features of horseradish extracts, and significant antibacterial activity has been shown against a wide range of pathogenic microbes.^{8, 9} It also has a symptomatic decongestant action and expectorant properties which can encourage the expulsion of excess mucus from the sinuses and bronchial tract. Its circulatory and digestive stimulant properties can also provide benefits where a weak or sluggish constitution is apparent or these functions go into an excessive element of hibernation, with the onset of winter.

Finally, our native Horopito (Pseudowintera colorata), is somewhat like horseradish in that it is both warming and has a tradition of use for chest infections, colds and asthma.¹⁰ Antibacterial and anti-inflammatory activities of polygodial and other sesquiterpenes found in these fiery plants, ^{11, 12} may contribute to their use as stimulating expectorants, and like horseradish, concomitant benefits on the gut are also likely. Anti-allergic and anti-anaphylactic properties have also been reported for polygodial,^{11, 13} suggesting potential applications also for asthma and allergic rhinitis, and I have used it successfully for these conditions.

References:

1. Extended pollen season picked up in pollen data. Pharmacy Today, 1 March 2024. The Health Media, Auckland. ISSN 1170-1927
2. Koster ES, Raaijmakers JA, Vijverberg SJ, van der Ent CK, Maitland-van der Zee AH. Asthma symptoms in pediatric patients: differences throughout the seasons. J Asthma. 2011;48(7):694-700.
3. Gerhardsson de Verdier M, Gustafson P, McCrae C, Edsbäcker S, Johnston N. Seasonal and geographic variations in the incidence of asthma exacerbations in the United States. J Asthma. 2017 Oct;54(8):818-824.
4. Bui TT, Piao CH, Song CH, Lee CH, Shin HS, Chai OH. Baicalein, wogonin, and Scutellaria baicalensis ethanol extract alleviate ovalbumin-induced allergic airway inflammation and mast cell-mediated anaphylactic shock by regulation of Th1/Th2 imbalance and histamine release. Anat Cell Biol. 2017;50(2):124-134.
5. Kao ST, Wang SD, Lin CC, Lin LJ. Jin Gui Shen Qi Wan, a traditional Chinese medicine, alleviated allergic airway hypersensitivity and inflammatory cell infiltration in a chronic asthma mouse model. J Ethnopharmacol. 2018 Dec 5;227:181-190.
6. Gulledge TV, Collette NM, Mackey E, et al. Mast cell degranulation and calcium influx are inhibited by an Echinacea purpurea extract and the alkylamide dodeca-2E,4E-dienoic acid isobutylamide. J Ethnopharmacol. 2018;212:166-174.
7. Rasmussen PL, Effects of human pollutants on plants: the case of Ribwort. www.herbblurb.com April 12, 2019
8. Goos KH, et al, Efficacy and safety profile of a herbal drug containing nasturtium herb and horseradish root in acute sinusitis, acute bronchitis and acute urinary tract infection in comparison with other treatments in the daily practice/results of a prospective cohort study]. Arzneimittelforschung. 2006;56(3):249-257
9. Hoch CC, Shoykhet M, Weiser T, et al. Isothiocyanates in medicine: A comprehensive review on phenylethyl-, allyl-, and benzyl-isothiocyanates. Pharmacol Res. 2024;201:107107.
10. Rasmussen PL, Pseudowintera spp (Horopito): a monograph. Aust J Herbal Med 2014; 26:150-154.
11. da Cunha FM, Fröde TS, Mendes GL, et al. Additional evidence for the anti-inflammatory and anti-allergic properties of the sesquiterpene polygodial. Life Sci. 2001;70(2):159-169.
12. Kubo I, Fujita K, Lee SH, Ha TJ. Antibacterial activity of polygodial. Phytother Res. 2005;19(12):1013-1017.
13. Kuroiwa K, Shibutani M, Inoue K, Lee KY, Woo GH, Hirose M. Subchronic toxicity study of water pepper extract in F344 rats. Food Chem Toxicol. 2006;44(8):1236-1244