(By Duan Wenli) A 15-year retrospective study with the world’s largest sample size in a single center led by Yin Jia, Jiang Nannan, Wen Liping and Li Hong from the Department of Allergy, PUMCH turns out the world’s first publication of sequenced causes to anaphylaxis among the Chinese people, as well as their distribution characteristics in different age groups. Published in The Allergy, Asthma & Immunology Research Journal, the study provides a “China list” to global research on anaphylaxis causes, fills the blank of epidemiological survey literature on anaphylaxis in China, and further testifies to the obvious regional difference in such causes.
Putting the 907 cases for further analysis in age groups, Yin Jia discovered that 68% of severe allergic reactions occur between the ages of 18-50, and the primary causes in different age groups are different. For 0-3 year-old infants, 62% of anaphylaxis is primarily caused by milk; for 4-9 year-old children, 59% is caused by fruits/vegetables. For teenagers and adults (above 10 years old) the primary cause is wheat, whose percentage rises with age. For example, wheat causes 20% of anaphylaxis among the 10-17 year group, but the percentage rises to 42% among the 18-50 year group. The lack of “gluten free” wheat products in China and genetic susceptibility may contribute to the high percentage of wheat-induced anaphylaxis in China, according to experts.
The study also found that food-induced anaphylaxis often occur together with pollen allergy, the most common one being mugwort pollen-food syndrome. Mugwort pollen sensitization was common in patients with anaphylaxis induced by spices, fruits/vegetables, legume/ peanuts, and tree nuts/seeds, with the prevalence rates of 75%, 67%, 61%, and 51%, respectively. Among 24 peach-related anaphylaxis cases, 17 (71%) were allergic to mugwort. Besides, the study also reported China-specific and rare food triggers, including chrysanthemum tea, bullfrogs, edible potherb, silkworm chrysalis, locusts and cicada.
Regarding the age at onset, the study reported that the occurrence of anaphylaxis in Chinese adults is much higher than in children, mostly among the 18-50 age group. According to Yin Jia, along with the process of industrialization and modernization, allergic diseases including anaphylaxis in China will display a tendency similar to those in western countries. Food-induced allergy in children may be a global trend.
The study also reported that 7% of anaphylaxis in Chinese people are drug induced. The first trigger is traditional Chinese medicine (37%), followed by antibiotics (24%), most commonly penicillin, and antipyretics and analgesics (16%).
According to the study, exercise is the most common aggravating factor. 39% of anaphylactic reactions occurred during exercise, 3.7% after orally taking aspirin, 1.4% occurred after alcohol consumption, 1.1% after taking non-steroidal anti-inflammatory drugs (NSAIDs) other than aspirin. Exercise involved in episodes triggered by foods (87%) as a co-factor. According to Yin, although drug-induced anaphylaxis is relatively few in number, more people are expected to take aspirin for a preventive purpose considering the rising of high blood pressure among Chinese people and its continuously proven effect in preventing stroke, Alzheimer's disease and anti-aging. Once clearly diagnosed as wheat-induced severe allergic reaction, aspirin and antipyretics and analgesics shall be an absolute contradiction; if aspirin or antipyretics and analgesics is necessary in treatment, then wheat-related food shall be an absolute contradiction.
According to the study, among the 640 with emergency treatment records, 72% were treated with corticosteroids and only 25% were treated with epinephrine; while the use of epinephrine in the United States reaches to 79%. Mastery of intramuscular injection of epinephrine may save oneself or others at a critical moment.