Spring is here, and all kinds of flowers are blooming in order to reproduce. What you may not know is that in satellite remote sensing images, the pollen concentration of Salicaceae and Coniferaceae plants in the vast land north of the 35° north latitude in China is increasing at a rate of 15% to 30% per day. This is the most spectacular way of biological diffusion in nature every year.

Image source: Pixabay

When these tiny particles carrying the code of life swept across the earth with the spring breeze, many of us began to experience all kinds of strange allergies every year! You know, in the air that is difficult to see with the naked eye, there are tens of thousands of pollen particles floating in every cubic centimeter, quietly knocking on the nasal cavities and bronchi of millions of pollen allergic people. The code of life dancing in the spring breeze also turns into an invisible hand. When people are itchy, with the help of their fingers, they draw fine scratches on the skin, making the skin that has been in close contact with spring appear slightly red ripples.

1. What is pollen allergy

Pollinosis is a non-infectious inflammatory disease of the nasal mucosa mediated by IgE after atopic individuals come into contact with allergenic pollen. It is a type I hypersensitivity reaction. Its pathogenesis involves three key links:

1. Sensitization stage: When people with allergic constitution first come into contact with pollen antigens, the body is stimulated to produce specific IgE antibodies, which bind to the surface receptors of mast cells/basophils.

2. Stimulation phase: When exposed to the same antigen again, the antigen cross-links with IgE to trigger cell degranulation and release inflammatory mediators such as histamine and leukotrienes.

3. Effect phase: Inflammatory mediators cause vasodilation, increased permeability, and glandular hypersecretion, manifesting as symptoms such as sneezing and runny nose [1].

Typical symptom classification:

Mild: intermittent nasal itching, ≤4 sneezes per day, mild itching in exposed areas (face/neck/limbs)

Moderate: Persistent nasal congestion with decreased sense of smell, nocturnal symptoms that interfere with sleep, erythema/urticaria on the skin that worsens with scratching

Severe: symptoms persist for ≥ 4 weeks, accompanied by asthma or eye inflammation[2], generalized rash with severe itching, affecting quality of life

2. Pollen allergy in history

Humans' knowledge of pollen allergy can be traced back to the "ophthalmia" recorded in Mesopotamian clay tablets in 2600 BC. The "spring fever" described in the ancient Greek "On Epidemics" and the "Rose Friar's Cough" in the Middle Ages were both early clinical observations. In the 16th century, Vesalius discovered foreign body deposition in the nasal cavity through autopsy, opening the prelude to the study of allergy mechanisms. In the 19th century, British doctor John Bright first established the temporal and spatial correlation between pollen concentration and symptoms. Charles Blakely confirmed the allergenicity of willow pollen through autologous experiments and invented the first pollen counter. The discovery of the histamine release mechanism in the 20th century gave rise to anti-allergic drugs. The advent of diphenhydramine in 1952 ended the millennium-long rhinitis problem.

In modern times, Japanese scholars have used gas chromatography to analyze the diffusion patterns of cedar pollen, gene sequencing to identify the IL-13 allergy gene, and NASA satellite data to reveal the quantitative relationship between forest coverage and morbidity. Swiss laboratories have cultivated zero-allergenic transgenic poplars, and the Chinese team has built an AI satellite network monitoring system to achieve minute-level warnings with a 93% prediction accuracy during the Beijing Winter Olympics. From ancient Egyptian herbal soups to gene editing, this cognitive revolution spanning five thousand years has proven that only by combining Blakely's scientific exploration with the Amazon tribe's natural awe can we find the wisdom of survival in symbiosis with all things in the flying catkins.

3. Invisible enemies: major allergens

1. Classification of plant pollen

2. Differences in sensitization mechanisms

Artemisia pollen: contains Artemisia vulgaris antigenic epitopes, which cross-react with dust mites (with an overlap of sensitization rates of up to 43%) [3].

Ragweed pollen: Amb a 1 protein is a strong allergenic substance, with 1 gram of pollen containing 2 million allergen particles[4].

Cypress pollen: The main allergen in Northwest my country, with a short flowering period (30-45 days) but strong explosiveness.

Image source: Pixabay

4. Epidemiological characteristics of allergies

1. Global epidemic situation

Incidence: WHO data show that the global prevalence has reached 10% to 30%, and is continuing to rise in industrialized countries[5].

Economic Costs: Allergic rhinitis causes billions of dollars in lost productivity in the United States each year[6].

2.2 Prevalence characteristics in China

3. Risks for special groups

Children: The younger the age of exposure, the higher the risk of developing persistent asthma (OR=2.34) [10].

Occupational exposure: The serum specific IgE levels of garden workers are 3 to 5 times higher than those of the general population [11].

Impact of climate change: Increased CO₂ concentrations can increase ragweed pollen production by 60%[12].

5. Multidimensional Treatment Strategy

1. Stepwise drug therapy

4. Innovation in immunotherapy

Cluster immunotherapy: shortens the traditional 15-week treatment course to 6 weeks.

Intralymphatic immunotherapy: Injection directly into the lymph nodes, with a 50% lower dose.

Recombinant allergen vaccine: removes allergenic protein fragments, improving safety by 3 times.

5. TCM special treatments

Yupingfeng Granules: Regulate Th1/Th2 balance and reduce the recurrence rate by 22%.

Acupoint application: Apply plasters on the lung and kidney points during the dog days of summer to improve allergic constitution.

Acupuncture intervention: Stimulating the Yingxiang and Hegu points can immediately relieve nasal congestion symptoms.

6. All-weather protection strategy

1. Environmental Control Matrix

Pollen season: Protect yourself indoors by using an air purifier and installing anti-pollen screens.

During commuting: For outdoor protection, wear an N99 mask and spray your hair with clean water to reduce pollen adhesion.

At home: air purification, 24-hour fresh air system, ultraviolet disinfection.

2. Dietary intervention

Recommended foods: Foods rich in quercetin (onions, apples) and Omega-3 (deep-sea fish).

Taboo foods: photosensitive foods such as nettles and celery (may aggravate symptoms).

Probiotic supplementation: Lactobacillus/Bifidobacterium can reduce IgE levels by 18%[13].

Supplement vitamin D (studies have found that skin sensitivity increases 2.7 times in those with vitamin D deficiency).

3. Sports protection

Avoid exercising outdoors in the early morning (6-8 am) and late evening (17-19 pm).

Pre-treat with sodium cromoglycate (nasal spray) before exercise.

Wear goggles + waterproof breathable mask during high-intensity exercise.

Shower promptly after exercise (to reduce pollen adhesion).

7. Clarification of cognitive misunderstandings

1. Myth: Pollen allergies only occur in spring

The truth: The disease can occur year-round, with ragweed pollen lasting from fall until November.

2. Myth: Taking cold medicine can relieve symptoms

The truth: Pseudoephedrine may aggravate nasal mucosal edema, and antihistamines are safer.

3. Myth: A negative allergen test can rule out the diagnosis

The truth: About 20% of patients suffer from "local allergic reactions", which require a nasal provocation test for diagnosis.

4. Myth: Using hot water to wash can relieve itching

The truth: High temperature destroys the skin barrier, leading to a vicious cycle of itching and scratching (cold compress + topical moisturizer is recommended).

References

[1] Principles of Immunology, 4th edition, edited by Cao Xuetao, Science Press

[2] “Guidelines for the diagnosis and treatment of allergic rhinitis (2022 revised edition)”

[3] Li et al. Allergy 2020;75(3):624-633

[4] Wang Zhengang et al. Chinese Journal of Otorhinolaryngology Head and Neck Surgery, 2021, 56(5): 521-526

[5] WHO Global Atlas of Allergic Rhinitis and Chronic Rhinosinusitis

[6] Bousquet et al. J Allergy Clin Immunol 2018;141(3):863-873

[7] Chinese Center for Disease Control and Prevention, Institute of Environment, “Air Pollution and Allergic Disease Monitoring Report (2023)”

[8] Shanghai Children’s Medical Center, “Ten-year cohort study of childhood allergic diseases”

[9] Qinghai Provincial People’s Hospital, “Epidemiological Survey on Pollinosis in the Qinghai-Tibet Plateau”

[10] New England Journal of Medicine 2022;386(12):1145-1156

[11] Journal of Occupational Health and Injury, 2023, 38(2): 134-138

[12] PNAS 2021;118(15):e2024323118

[13] Chinese Journal of Traditional Chinese Medicine, 2023;38(7):2892-2897

Source: Chongqing Science Writers Association

Written by: Gao Xu, a 2020 preventive medicine major at the School of Public Health of Chongqing Medical University, Wang Ya, deputy chief physician, Zou Jingbo, chief technician, and Jiang Xuefei, deputy chief physician at the Chongqing Yongchuan District Center for Disease Control and Prevention

Audit expert: Li Hanbin

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