HYOGO, Apr 26, 2026 (News On Japan) - Allergies caused by pollen, house dust, eggs, wheat and other substances found in everyday life have become so widespread in Japan that they are now often described as a national condition, but medical specialists say nut allergies are drawing particular concern after increasing nearly tenfold over the past decade and showing a tendency to appear at younger ages.
At a clinic in Sanda, Hyogo Prefecture, an 11-month-old baby was seen undergoing a skin test to identify possible allergies to wheat, soybeans and eggs. Allergies occur when the immune system overreacts after a substance enters the body, sometimes damaging the body itself. Doctors say roughly one in two people now has some form of allergy, and the total number appears to be higher than in the past.
Among food allergies, eggs, wheat and milk have long been known as the three major causes. However, nut allergies have been rising at an unusually fast pace. In severe cases, they can cause not only itching and rashes but also anaphylaxis, a potentially life-threatening reaction.
The number of nut allergy cases has increased about tenfold over the past 10 years, and allergies caused by nuts are now said to rank second after eggs. At a clinic in Osaka, twin first-grade sisters were being treated for allergies to walnuts and hazelnuts. One of the sisters can eat only a small amount, while the other cannot eat them at all. Their mother recalled that the allergy was discovered after walnuts in a cookie caused itching in the mouth and a rash across the body.
A junior high school student who developed an allergic reaction after eating pistachios in third grade said he felt tightness in his chest and became unwell after eating them. Since then, he has avoided pistachios. Doctors warn that pistachios are now often used in cookies and chocolate, meaning foods with a greenish color may contain them and require caution.
Fujitani, head of the clinic, said nut allergies tend to cause relatively severe symptoms and are increasingly appearing at younger ages. One reason behind the rise, he said, may be the growing domestic consumption of nuts.
In response to the trend, Japan's Consumer Affairs Agency added walnuts from April 1st to the list of specified ingredients that must be labeled because they may cause allergies. Pistachios were also added to the list of ingredients for which labeling is recommended. However, because a two-year transition period is in place, some products may still lack labels, making continued caution necessary.
As food allergies can be fatal in the worst cases, more businesses are beginning to take consumer safety into account. At one bakery, none of the so-called major allergenic ingredients, including wheat, are used. The owner, who is allergic to wheat, said one of the most rewarding moments is seeing the expression on a child with allergies when their parent tells them they can choose anything in the shop.
Testing technology is also advancing. At one clinic, a blood allergy test that once took about a week can now check 45 items in just 15 minutes. Two program staff members underwent the test. One, who had never noticed allergy-like symptoms, was found to have a positive reaction to cedar pollen. Another, who had once required emergency treatment after eating tantanmen and suspected an allergy to peanuts used in the paste, was found to be in the most severe class for overall allergy tendency, with a strong positive reaction to peanuts. The test also revealed strong reactions to house dust, dust mites, cats and cedar, despite the person having had no awareness of some of them.
Doctors say such rapid tests can be useful in helping people understand their own risks and avoid danger before symptoms occur. Treatment methods are also changing. At the clinic, an 11-month-old boy who had been diagnosed with a milk allergy after developing hives from yogurt during baby food weaning was given milk as part of an oral food challenge test.
The doctor explained that children with milk allergies do not necessarily need to avoid milk completely. Many have a threshold amount they can tolerate, and continuing to consume that amount may help lead to improvement. In this case, a mild reaction appeared during the test, so the result was left pending, and the child was instructed to continue drinking the same amount each day.
While allergies were once widely viewed as lifelong conditions, specialists say some may improve with proper diagnosis and treatment. They advise patients to consult an allergy specialist, especially as knowing one's own allergens can help guide daily precautions and treatment.
Source: KTV NEWS
