Guides · 花粉症 · kafunshō
Hay Fever in Japan — Surviving Cedar Season Like a Local
Every February, a sizeable share of Japan starts sneezing at once. Newcomers who "never had allergies" are regularly ambushed in their second or third spring — hay fever can begin at any age, and the exposure here is unlike most places on earth. This is the one condition your Japanese colleagues will diagnose in you before any doctor does, and they'll probably be right.
Why it's so bad here
The dominant culprit is Japanese cedar (スギ, sugi) pollen from vast postwar timber plantations covering roughly a tenth of the country's land area, joined by hinoki cypress (ヒノキ) whose season follows immediately after. The scale of the problem is well documented: in the most recent nationwide epidemiological survey (2019), 38.8% of the population had cedar pollinosis — up from 16.2% in 1998 — and about half had some form of allergic rhinitis. This is a mainstream national condition with correspondingly mature infrastructure: pollen forecasts on the nightly weather report, entire drugstore aisles, and a dedicated word for everything.
The calendar, for most of Honshu: cedar from mid-February to early April, cypress from late March through early May (many people react to both — a continuous 3-month season), grasses in early summer, and ragweed/mugwort in autumn. Hokkaido largely escapes cedar (its spring nemesis is birch); Okinawa escapes almost everything.
First-line: the drugstore, legitimately
For typical symptoms — sneezing, watery nose, itchy eyes — starting at the drugstore is reasonable and is what most residents do. Modern second-generation antihistamines are available OTC in Japan under the same active ingredients you may know: fexofenadine (アレグラ), loratadine (クラリチン), epinastine (アレジオン), cetirizine. These are non-drowsy or minimally drowsy and evidence-backed. Avoid relying on older first-generation formulas (often sold in combination products) for daily use — the sedation is real and affects driving.
Two OTC additions with good evidence: antihistamine or cromoglicate eye drops, and — now OTC as well — nasal corticosteroid sprays (フルチカゾン/beclomethasone products), which treat congestion better than antihistamines do. The Japanese habit toolkit also genuinely helps at the margins: masks (a normal, unremarkable act here), glasses, checking the pollen forecast (飛散情報), and not line-drying laundry on high-pollen days.
When to see a doctor instead
Go to an ENT (耳鼻咽喉科) or allergy-savvy internist if OTC control is incomplete, symptoms disturb sleep or work, you're unsure it's actually allergy (one-sided symptoms, fever, or smell loss point elsewhere), or you're facing your first full season and want a proper diagnosis. A blood test panel (specific IgE, e.g. View39) can confirm which pollens and dust mites you react to — useful once, at ~¥5,000 as your 30% share.
Prescription treatment is cheap here and adds options OTC can't: stronger or better-tolerated antihistamines (bilastine, rupatadine), leukotriene antagonists for congestion, prescription-strength nasal steroids, and short courses of stronger eye drops. What a good doctor will not do is inject long-acting corticosteroids for the season — a practice you may find offered at the fringes; the risk-benefit is poor and Japanese allergy guidelines discourage it.
The actual fix: sublingual immunotherapy
Japan is one of the easiest countries in the world to get sublingual immunotherapy (舌下免疫療法, SLIT) — daily under-the-tongue tablets that retrain the immune response. Standardized tablets exist for the two big perennial enemies: cedar pollen (シダキュア) and house dust mite (ミティキュア), both covered by insurance — roughly ¥1,000–2,000 per month at 30% plus periodic visits.
The honest terms of the deal: the first dose is taken at the clinic under observation; treatment continues daily for 3–5 years; and in return, large trials and a decade of Japanese clinical experience show most patients get substantially milder seasons — a meaningful fraction becoming nearly symptom-free — with benefits persisting after stopping. It is the only treatment that changes the disease rather than muffling it. Enrollment for cedar SLIT typically opens outside pollen season (roughly June–November) — you cannot start during the spring you're suffering through, which is exactly why it's worth arranging in the calm months. Children can start from around age 5.
Two roommates of hay fever worth knowing
Pollen-food allergy syndrome: some birch- and alder-sensitized people (notably in Hokkaido) get mouth itching from raw apples, peaches or soy milk — mention it if you notice it. And "Kafunshō or COVID/flu?" comes up every February: itchy eyes and sneezing fits point to allergy; fever and sore throat do not. When unsure — especially with fever — test or see a doctor rather than assuming.
General information, not individual medical advice. Prevalence figures are from the 2019 national nasal allergy survey; treatment statements follow current Japanese allergic rhinitis guidelines. If you have asthma, uncontrolled symptoms, or are considering immunotherapy, the treatment decision belongs with your doctor.