Allergies on the rise – why?
Herbalists are seeing steadily increasing numbers of people presenting with allergies, including food allergies, in their clinical practices. People are having stronger symptoms and more hypersensitivity reactions. Various allergic diseases such as asthma, hay fever, urticaria, atopic dermatitis and allergic rhinitis are now affecting nearly 20% of the population across the world, and children are more affected than adults. (1)
There seem to be several external and internal factors contributing to this rise in allergies.
The outwards picture – External factors
The general consensus is, unfortunately, that climate change and environmental factors stemming from it, such as air and chemical pollution, pesticides, insecticides, heavy metals, wildfires, soil quality degradation, longer flowering seasons due to heatwaves (hence longer exposure to pollen), all contribute to the rise seen in allergies in the recent decades. (2, 3, 4) Interestingly, plants growing in polluted areas with higher exposure to carbon dioxide also release more pollen. (4)
Air pollution is implicated in worsening allergic reactions in city dwellers especially, when the grasslands and thus the exposure to grass pollens in the cities are reducing in the last two decades. Cross-reactivity reactions predispose sensitive individuals to pollen and certain food allergies. (5)
The inwards picture – Internal factors
Toxicity and oxidative stress
As external factors befall on wide population, it is clear that internal factors play a major and most likely the decisive role in individual susceptibilities in developing various allergies. Exposure to toxins and allergens creates oxidative stress in the body, immune dysregulation and consequent inflammatory response. (6) For those individuals who have lowered antioxidant status in their tissues (because of lack of nutrients due to poor diet or genetic predisposition in detoxifying chemicals, toxins and heavy metals) this would add to their load of risk factors.
Gut, lungs and skin microbiome disturbances
Herbalists have always paid attention to gut integrity and the latest scientific research confirms the importance of gut microbiome in many inflammatory conditions, including allergies and asthma. (7) The significance of more recently discovered skin and lungs microbiome and its protective effects is also been investigated. (8)
Dysbiosis â a disturbed gut microflora, is the epicentre of immune and inflammatory imbalances leading to allergic reactions. (9) Gut microflora in children can be affected by a variety of components, such as use of antibiotics, the use of probiotics, dietary fats and fibre, and more. The rise in C-section births might be a possible risk factor in some children for developing allergies. (10) On the other hand, the protective effect of breastfeeding (especially for 6 weeks to 6 months) is also well documented. (11) In adults, the use of antacids (PPIs), antibiotics, NSAIDs and other medications is hugely disruptive to microbiome and the gut lining integrity, leading to dysbiosis and increased permeability of the intestines (‘leaky gut’). Food allergies are also linked with dysbiosis. (12) The main culprits are peanuts, cow milk, wheat, egg, soy, fish, shellfish and tree nuts.
The importance of healthy mucosal layer and its protective function is well known, but recently its immune function also has been recognised. (13)
Immune dysregulation and inflammation
As previously mentioned, the imbalances in gut microbiome lead to immune dysregulation, which in turn creates inflammation. Allergies are driven by T helper (Th) 2 responses, mast cell activation and the release of numerous inflammatory cytokines, such as IL-4 and IL-13 and histamine. (14) Adding fermented foods or probiotics and eating plenty of dietary fibre has a huge protective role in gut health. Prebiotics are also very important. Commensal gut bacteria ferments fibre into short-chain fatty acids (SCFA), which supports gut lining integrity and regulates immune system response via gut-associated lymphatic tissue (GALT). (15, 16) The latest research shows that regulatory T cells (Treg) have an important balancing effect on immune system and can dampen an allergic response triggered by T helper (Th) 2 cells. (17)
The bigger picture – Biodiversity hypothesis
The older concept of âhygiene hypothesisâ introduced by David Strachan in 1989 has been explored for several decades and suggests that increased hygiene and smaller families (less siblings) lead to reduced exposure to infections and can predispose children to developing allergies later on. (18) This partly can be explained by a lack of protective bacteria. Furthermore, research shows that decreased intestinal microbial diversity is an important risk factor for increased susceptibility to allergies. (19)
The newer biodiversity hypothesis has expanded the understanding of various internal and external factors affecting the microbiome. (20) As the biodiversity in nature surrounding us (our external microbiome) is reducing and changing, so is our inner microbiome becomes diminished, its diversity reduced, and it has to adapt to changes. The immune system (and the nervous system, for sure!) is trying to catch up and this leads to rise in allergies and immune dysregulation.
How can herbal medicine help?
It is widely recognised that herbal medicine can help to address the above-mentioned complexities and to correct the arising imbalances in the body. To meet and correct the imbalances arising from such above-mentioned complexities the multifaceted approach employing complex herbal medicines is needed. Obviously, the herbalists look at the individualâs constitution and their presenting symptoms, which will direct their choice of herbs. Here some possible, more general herbal choices used in treating allergies will be discussed. The list of herbs is not complete and other choices can be made as required.
Allergic rhinitis (AR)
Main signs & symptoms are runny nose with clear mucus, congestion and sneezing. Eyes can also be affected.
In traditional western herbalism, according to Matthew Wood (2004), this energetic picture of AR could be described as a predominantly damp and cold tissue state, with deficiency underneath. The use of warming, aromatic, spicy, clearing, astringent herbs is indicated to reduce catarrh (damp), clear congestion, reduce allergic response, support the mucosal lining.
Herbs:
Urtica dioica – Nettles
Clinical experiences shared by many herbalists and scientific analyses of the plant, as well as traditional uses across many countries brings nettle into forefront of a group of herbs used for allergies. (22, 23, 24) Sambucus nigra â elderberries and elderflowers are traditionally also used to support immunity, to reduce catarrh, clear congestion, reduce inflammation. (22) Zingiber officinalis – ginger is a warming, aromatic, pungent spice, which helps to reduce catarrh and nasal congestion. (25) Curcuma longa – turmeric is probably one of the most researched herbs. Traditional and scientific research shows a strong anti-inflammatory effect, useful in allergies and other inflammatory conditions. (26)
Urtica dioica folia, Sambucus nigra (flos & fructus), Zingiber officinalis, Curcuma longa
Vitamin C (citrus, peppers, broccoli, blackcurrants) and quercetin (onions, apples, citrus, green leaves) can be added as supplements or through foods. Black pepper is great to clear runny nose and is traditionally used in Ayurvedic medicine to clear catarrh. Warm aromatic and astringent teas – ginger, cinnamon, green tea, can be very useful.
In chronic AR or prevent recurrent episodes, immune modulating herbs such as Astragalus membranaceus can be added to the mix or used in between the flare ups (27).
Urticaria/ hives
Main signs & symptoms are red itchy wheals – rash on the skin.
In traditional western herbalism, this energetic picture of urticaria could be described as a predominantly a hot tissue state. The stagnation of the tissues (especially the liver and lymph) might be present. Stress is often a strong aggravator, as well as eating allergenic foods.
The use of cooling, detoxifying herbs, having a traditional âalterativeâ action on the tissues â cleansing and clearing, to help to reduce inflammation, modulate the immune response, support the integrity of the gut and the function of the liver. Nervous system support is often needed in this condition.
Herbs:
Matricaria recutita â German camomile is traditionally used in Europe as a tea for allergies, congestion, to reduce inflammation and pain. It also has an anxiolytic and calming effect (28) Caution- sensitivity to Asteraceae family can cause allergic reactions. Albizzia julibrissin â Albizzia or silk tree is traditionally used in TCM and Ayurvedic medicine to help to reduce allergic reactions and ameliorate symptoms such as itching or wheezing. (29) It is also has a calming, anxiolytic and antidepressant effect, as indicated in ethnobotanical studies and traditional uses. So it can be very useful in various acute and stressful allergic conditions, including urticaria.
Urticaria dioica folia, Matricaria recutita, Albizzia julibrissin, Arctium lappa radix
Externally creams are used in the herbal clinical practice with Stellaria media â chickweed or Aloe vera to help to reduce itchiness and soothe skin irritations. Vitamin C and quercetin supplements could be useful too, as well as pre- & probiotics (if not further causing more histamine release) to support gut microbiome.
Asthma
Main symptoms are wheezing, cough, tightness of chest, shortness of breath, which might be aggravated on physical exertion, exposure to cold air, on exposure to allergens or with emotional stress.
Asthma is a complex inflammatory disease. Depending on the severity of it, whether it is chronic or acute, and on the constitutional individualâs type, in traditional western herbalism the energetic picture of asthma could be described as a deficient and stagnant condition with an accumulation of damp, heat, cold or/and dryness in the tissues.
The use of herbs to help to reduce inflammation (heat), reduce cough, expel mucus (damp), relax bronchospasm, modulate the immune response, support the integrity of the gut and microbiome. Nervous system support is also often needed in this condition and herbs traditionally called nervines can be very helpful.
Herbs:
Curcuma longa, Inula helenium, Thymus vulgare, Verbascum thapsus, Glycyrrhiza glabra (31)
Herbs to feed gut microbiome, to support biodiversity of microflora and gut health, to support digestion and intestinal absorption, such as Arctium lappa radix and Inula helenium are traditionally used by herbalists. Mucosal membranes and epithelial integrity can be supported by using mucilage – rich herbs such as Althea offcinalis, Aloe vera or Glycyrrhiza glabra.
Additional advice
As allergies always have an inflammatory component, increasing anti-inflammatory unprocessed plant-based foods in the diet is important, as well as feeding the microbiome with plenty of fibre and staying hydrated to support elimination processes.
References
- Bantz SK, Zhu Z, Zheng T., 2014. The atopic march: progression from atopic dermatitis to allergic rhinitis and asthma. Journal of Clinical & Cellular Immunology. 5:202
- Mattila T, Santonen T, Andersen HR, et al., 2021. Scoping Review-The Association between Asthma and Environmental Chemicals. International Journal of Environmental Research and Public Health. 1;18(3):1323.
- DâAmato G & Akdis CA, 2020. Global warming, climate change, air pollution and allergies. European Journal of Allergy and Clinical Immunology. https://doi.org/10.1111/all.14527
- Chatkin J, Correa L, Santos U., 2021. External Environmental Pollution as a Risk Factor for Asthma. Clinical Reviews in Allergy & Immunology. 12;1-18.
- DâAmato G, 2007. The UCB Institute of Allergy; Pollen Allergy in Europe. Available online: https://www.ucb.com/_up/tuioa_com/images/PollenAllergy-DAmato-simplified-V2-070910_PP.pdf.
- Schaumann F, FrĂśmke C, Dijkstra D., 2014. Effects of ultrafine particles on the allergic inflammation in the lung of asthmatics: results of a double-blinded randomized cross-over clinical pilot study. Particle and Fibre Toxicology. 1:39
- Aguilera, A. C., Dagher, I. A., & Kloepfer, K. M. (2020). Role of the Microbiome in Allergic Disease Development. Current allergy and asthma reports, 20(9): 44.
- Ver Heul A, Planer J, Kau AL., 2019. The human microbiota and asthma. Clinical Reviews in Allergy & Immunology. 57(3):350-363.
- Yang, L., Fu, J., & Zhou, Y., 2020. Research Progress in Atopic March. Frontiers in Immunology. 11:1907
- Kristensen K & Henriksen L., 2016. Cesarean section and disease associated with immune function. Journal of Allergy & Clinical Immunology. 137:587â90
- Taylor-Robinson DC, Williams H, Pearce A et al., 2016. Do early life exposures explain why more advantaged children get eczema? Findings from the U.K. Millennium Cohort Study. British Journal of Dermatology. 174:569â578
- Suther C, Moore MD, Beigelman A, et al., 2020. The Gut Microbiome and the Big Eight. Nutrients. 12(12):3728
- Frey A, Lunding LP, Ehlers JC et al., 2020. More Than Just a Barrier: The Immune Functions of the Airway Epithelium in Asthma Pathogenesis. Frontiers in Immunology. 28;11:761.
- Galli, S. J., & Tsai, M. (2012). IgE and mast cells in allergic disease. Nature medicine, 18(5), 693â704.
- Kim, J. E., & Kim, H. S. (2019). Microbiome of the Skin and Gut in Atopic Dermatitis (AD): Understanding the Pathophysiology and Finding Novel Management Strategies. Journal of clinical medicine, 8(4), 444.
- Bunyavanich, S., & Berin, M. C. (2019). Food allergy and the microbiome: Current understandings and future directions. The Journal of Allergy & Clinical Immunology, 144(6), 1468â1477.
- Wang W, Wei C, Cheng Z et al., 2020. Aberrant Th2 Immune Responses Are Associated With a Reduced Frequency of IL-35-Induced Regulatory T Cells After Allergen Exposure in Patients With Allergic Asthma. Allergy, Asthma & Immunology Research. 12(6):1029-1045.
- Penders J, Gerhold K, Thijs C et al., 2014. New insights into the hygiene hypothesis in allergic diseases: mediation of sibling and birth mode effects by the gut microbiota. Gut Microbes. 5(2):239-44.
- Abrahamsson TR, Jakobsson HE, Andersson AF et al. (2014). Low gut microbiota diversity in early infancy precedes asthma at school age. Clinical and Experimental Allergy. 44:842â50.
- Haahtela T, 2019. A biodiversity hypothesis. Allergy. 74(8):1445-1456.
- Matthew Wood, 2004. The Practice of Traditional Western Herbalism: Basic Doctrine, Energetics and Classification. North Atlantic Books, Berkeley, California
- Sayin, I., Cingi, C., Oghan, F. et al (2013). Complementary therapies in allergic rhinitis. ISRN allergy, 2013: 938751. https://doi.org/10.1155/2013/938751
- Roschek B Jr, Fink RC, McMichael M, et al., 2009. Nettle extract (Urtica dioica) affects key receptors and enzymes associated with allergic rhinitis. Phytotherapy Research. 23:920â6.
- Kregiel D, Pawlikowska E, Antolak H., 2018. Urtica spp.: Ordinary Plants with Extraordinary Properties. Molecules. 9;23(7):1664
- Yamprasert, R., Chanvimalueng, W., Mukkasombut, N., et al (2020). Ginger extract versus Loratadine in the treatment of allergic rhinitis: a randomized controlled trial. BMC complementary medicine and therapies, 20(1), 119.
- Debjit Bhowmik C, Kumar KS, Chandira M, et al. 2009. Turmeric: a herbal and traditional medicine. Archives of Applied Science Research. 1 (2)86-108
- Matkovic Z, Zivkovic V, Korica M, et al. 2010. Efficacy and Safety of Astragalus membranaceus in the Treatment of Patients with Seasonal Allergic Rhinitis. Phytotherapy Research. 24: 175â18
- Srivastava JK, Shankar E & Gupta S., 2010. Chamomile: A herbal medicine of the past with a bright future (Review). Molecular Medicine Reports. 3: 895-901.
- He Y, Wang Q, Ye Y, et al, 2020. The ethnopharmacology, phytochemistry, pharmacology and toxicology of genus Albizia: A review. Journal of Ethnopharmacology. 257:112677
- Manarin G, Anderson D, Silva JME, et al, 2019. Curcuma longa L. ameliorates asthma control in children and adolescents: A randomized, double-blind, controlled trial. Journal of Ethnopharmacology. 238:111882.
- Kelly-Pieper K, Patil SP, Busse P,et al., 2009. Safety and Tolerability of an Antiasthma Herbal Formula (ASHMIâ˘) in Adult Subjects with Asthma: A Randomized, Double-Blinded, Placebo-Controlled, Dose-Escalation Phase I Study. Journal of Alternative and Complementary Medicine. 15(7):735-43.