Substance Info: (and synonyms)
Japanese cedar tree / Sugi tree / Japanese red cedar tree

Background Info:

Not to be confused with Cedar tree.

Japanese cedar, also called the Sugi tree, is an evergreen growing 30 to 50 metres tall. It grows in woods, often in pure stands, in rich deep soils in places sheltered from strong winds. Its needles shift from a pale opal in the summer to bright red towards the autumn. It is the most important timber tree in Japan, where about one third of the area under cultivation is devoted to it. There the tree is often planted in temple gardens and along roads leading to the temples. Japanese cedar pollen is the most common allergen for seasonal allergic rhinitis in Japan.

Japanese cedar is native to Japan and the coastal provinces of China, and often cultivated in Europe and North America.

The male Japanese Cedar tree flowers between February and April. However, Japanese children born during the winter months of November to January, and who were exposed to Japanese Cedar pollen within the first 6 months of life, demonstrated increased risk of sensitisation to this pollen (determined by serum-specific IgE), and especially severe sensitisation. A previous study demonstrated that the male Sugi flowers disperse a small amount of pollen in early January and that this may result in some Japanese Cedar pollinosis patients experiencing allergic symptoms as early as January.


Adverse Reactions:


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An Internet questionnaire survey of Japanese patients with Japanese cedar pollinosis was conducted in mid-May 2011 and responses were obtained from 3382 individuals who had potential symptoms of Japanese cedar pollinosis from February to early May 2011 and who had experienced such symptoms for at least two pollen seasons. According to PG-MARJ, 23.5% of the respondents had severest rhinitis, 29.4% severe rhinitis, 31.3% moderate rhinitis, 13.8% mild rhinitis and 2.0% asymptomatic rhinitis. According to ARIA, 67.2% of them had moderate/severe persistent rhinitis, 23.8% moderate/severe intermittent rhinitis, 4.4% mild persistent rhinitis and 4.6% mild intermittent rhinitis. (Gotoh 2013 ref.28756 7)

Gotoh M, Yuta A, Okano M, Ohta N, Matsubara A, Okubo K. Severity assessment of Japanese cedar pollinosis using the practical guideline for the management of allergic rhinitis in Japan and the allergic rhinitis and its impact on asthma guideline. Allergol Int 2013 Feb 25;

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These results suggest that both house dust mite allergen and outdoor allergens such as cedar pollen can be causes of allergic conjunctivitis during both spring and autumn in Japan. The Immfast Check J1 provides rapid measurement of specific IgE in tear fluid, which allows easy diagnosis of allergic conjunctivitis in an outpatient setting. (Mimura 2011 ref.26772 5)

Mimura T, Usui T, Mori M, Funatsu H, Noma H, Amano S. Specific tear IgE in patients with moderate-to-severe autumnal allergic conjunctivitis. Int Arch Allergy Immunol 2011 Aug 9;156(4):381-386

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Seasonal allergic rhinitis caused by Japanese cypress pollen is highly associated with that by Japanese cedar pollen, due to the similar antigen of the two pollens. Clinically, patients with cypress pollinosis complain of strong throat symptoms. Weekly nasal and throat symptoms during the pollen season in patients with Japanese cedar-cypress pollinosis were measured using a visual analog scale (VAS). VAS showed that nasal symptoms appeared parallel with pollen scattering, and that they were severe in the cedar season more than in the cypress season. On the other hand, throat discomfort and cough were worse in the cypress season, even though this study took place of during a year when there was only a small amount of cypress-pollen scattering. The severity of symptoms other than rhinoconjunctivitis in cedar pollinosis depended on the total amount of pollen, however, cypress pollinosis showed severe throat symptoms in both a small and a mass scattering year. Therefore although cypress and cedar pollinosis is considered as the same disease, cypress pollinosis showed more severe symptoms other than rhinoconjunctivitis. Throat symptoms in particular are more severe in cypress pollinosis, even in the year of a small amount of scattering. (Ogihara 2011 ref.26348 5)

Ogihara H, Yuta A, Miyamoto Y, Kitano M, Takeo T, Takeuchi K. Increased throat symptoms in Japanese cypress pollinosis. [Japanese] Nippon Jibiinkoka Gakkai Kaiho 2011 Feb;114(2):78-83

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A 7-year-old monozygotic twin patients with atopic dermatitis. Both serum IgE levels and cedar pollen RAST scores were high in the twins (elder/younger sister: IgE: 5170/3980IU/ml and Japanese cedar pollen: >100/64.0) in contrast to low mite and food RAST scores. The patients showed positive immediate (20 min in both sisters) and delayed (24 hours in elder sister, 24, 48, 72 hours in younger sister) reactions to a scratch test with Japanese cedar pollen. Skin lesions on the face were aggravated and extended to the trunk and extremities during the Japanese cedar pollen season and gradually subsided in summer. Oral provocation with egg white or cow milk showed no exacerbations, and topical corticosteroid did not improve the eczema. In contrast, successful protection from severe scratching behaviors was achieved by use of topical anti-allergic eye drops and wearing nightgowns made by the mother. (Murakami 2011 ref.25958 2)

Murakami Y, Matsui S, Kijima A, Kitaba S, Murota H, Katayama I. Cedar Pollen Aggravates Atopic Dermatitis in Childhood Monozygotic Twin Patients with Allergic Rhino Conjunctivitis. Allergol Int 2011 Mar 25;

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The amount of airborne pollen may be predictive of both symptom severity and treatment outcome. (Takasaki 2008 ref.22134 7)

Takasaki K, Enatsu K, Kumagami H, Takahashi H. Relationship between airborne pollen count and treatment outcome in Japanese cedar pollinosis patients. Eur Arch Otorhinolaryngol 2009 May;266(5):673-6.

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Cedar and cypress pollinosis and allergic rhinitis (Sasaki 2009 ref.28737 7)

Sasaki K, Okamoto Y, Yonekura S, Okawa T, Horiguchi S, Chazono H, Hisamitsu M, Sakurai D, Hanazawa T, Okubo K. Cedar and cypress pollinosis and allergic rhinitis: quality of life effects of early intervention with leukotriene receptor antagonists. Int Arch Allergy Immunol 2009;149(4):350-8.

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The results indicate that pranlukast hydrate inhibits airway hyperresponsiveness in non-asthmatic patients with Japanese cedar pollinosis. (Sagara 2009 ref.28736 0)

Sagara H, Yukawa T, Kashima R, Okada T, Fukuda T. Effects of pranlukast hydrate on airway hyperresponsiveness in non-asthmatic patients with Japanese cedar pollinosis. Allergol Int 2009 Jun;58(2):277-87.

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In Japan, Japanese cedar (Cryptometria japonica) and Japanese cypress (Chamaecyparis obtusa) pollens are considered to be the major unique allergens and their extent of dispersal is quite large, travelling more than 100km and thus causing serious pollinosis. This study examined the number of Japanese cedar pollen specific memory Th cells in the peripheral blood of the patients and found that the cedar pollen specific IL-4-producing Th2 memory cells increased during the pollen season and decreased during the off-season. However, more than 60% of the cedar-specific memory Th2 cells survived up to 8 months after the pollen season. (Okamoto 2009 ref.23303 7)

Okamoto Y, Horiguchi S, Yamamoto H, Yonekura S, Hanazawa T. Present Situation of Cedar Pollinosis in Japan and its Immune Responses. Allergol Int 2009 Mar 25;58(2):

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The prevalence of Japanese cedar pollinosis is high to 26.5%, and it is properly remarked as 'national disease' in Japan. Papilla(R), commercial name of one kind of health foods, is a capsular packed with cedar pollen. A 49-year-old female patient presented with anaphylaxis after intake of Papilla(R) capsule. Special-IgE antibody and histamine release test were both positive to cedar pollen. Although Cry j 1, the major allergen in the Papilla(R) capsular was a small amount, the cause of anaphylaxis can not be attributed to anything except the pollen contents in this product. (No 2009 ref.23021 3)

No authors listed A case presenting anaphylaxis shock after intake of capsule packing cedar pollen.. [Japanese] Arerugi 2009 Jan;58(1):39-44

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Oral allergy syndrome (OAS) to plant foods is often caused by cross-reactivity to pollen. This study investigated whether there was any significant correlation between sensitization to the pollen of alder and Japanese cedar flying off in spring and prevalence of OAS in Yokohama region. Specific IgE antibodies against alder and Japanese cedar in 337 outpatients with skin allergy in 2005 was assessed. Ratio of positive response to CAP against alder was 23.4% (79 cases) while that to CAP against Japanese cedar was 73.7% (244 cases). Response to CAP against rBet v 1 and rBet v 2 was tested in 55 cases, and the ratio of positive response to CAP against rBet v 1 was 43.6% (24 cases) while that to CAP against rBet v 2 was 27.3% (15 cases). Prevalence of OAS showed a significant positive correlation (p<0.001) with sensitization to alder, but no correlation with sensitization to Japanese cedar. Therefore is suggests that sensitization to alder pollen would be involved in prevalence of OAS in Yokohama region. (Morita 2008 ref.21413 2)

Morita A, Inomata N, Kirino M, Ikezawa Z. Correlation of oral allergy syndrome due to plant-derived foods with alder pollen, rbet v 1 and rbet v 2 sensitization in Yokohama region. [Japanese] Arerugi 2008 Feb;57(2):138-146

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Japanese cedar is the most common allergen in rhinitis in Japan but is controversial on whether it can provoke asthma. Adult patients who were sensitized only to the Japanese cedar (CAP-RAST > = 2) and had symptoms of asthma during the cedar season were studied. 6 adult asthma patients who fulfilled the two criteria were found. Five patients suffered from cedar pollinosis in addition to asthma, and 1 patient had no pollinosis. The cedar pollinosis preceded asthma in 3 cases and occurred at almost the same time in the other 2 cases. Pulmonary function was normal in these cases, with a high threshold value in the non-specific airway hypersensitivity test and low total IgE. In the allergen provocation test, 3 subjects showed both an immediate and late asthmatic reaction. The study concludes that Japanese cedar pollen could provoke not only pollinosis but also asthma in adults. (Maeda 2008 ref.22643 7)

Maeda Y, Akiyama K, Shida T. A Clinical Study of Japanese Cedar (Cryptomeria japonica) Pollen-Induced Asthma. Allergol Int 2008 Nov 1;57(4):413-417

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Airborne contact dermatitis after contact with Japanese cedar pollen [Japanese cedar pollen dermatitis (JCPD)] has been reported in Japan. A scratch-patch test, scratch test and assays for total immunoglobulin E (IgE) and specific IgE was performed in 13 patients suspected to have skin symptoms from Japanese cedar pollen, 5 patients with Japanese cedar pollinosis. 100% of the 13 patients with JCPD showed a positive scratch-patch-test reaction to Japanese cedar pollen extract. However, 20% of the patients with the Japanese cedar pollinosis without any eruptions showed a positive scratch-patch-test reaction. The percentage of positive results for specific IgE and the scratch test did not differ substantially between Japanese cedar pollionosis patients with a history of chronic erythema after contact with Japanese cedar pollen and those without such a history. Control subjects showed 7% positive reaction. Histological examination showed that eczematous change (spongiosis, intracellular oedema and acanthosis), and infiltration of lymphocytes and eosinophils were all observed at the scratch-patch-test-positive sites. We therefore concluded that the use of the scratch-patch test with Japanese cedar pollen extract was useful for accurately diagnosing JCPD. (Yokozeki 2007 ref.22143 3)

Yokozeki H, Satoh T, Katayama I, Nishioka K. Airborne contact dermatitis due to Japanese cedar pollen. Contact Dermatitis 2007 Apr;56(4):224-8.

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The occurrence of Japanese cedar pollinosis with rheumatoid arthritis. (Koizumi 2007 ref.22142 2)

Koizumi K, Okamoto H, Kamitsuji S, Sato E, Suzuki K, Yamanaka H, Hara M, Tomatsu T, Kamatani N. The occurrence of Japanese cedar pollinosis with rheumatoid arthritis. Clin Exp Rheumatol 2007 May-Jun;25(3):505-6.

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A report on 16 cases of childhood OAS in a Japanese study. The rate of sensitization against four major pollens (Japanese cedar, orchard grass, short ragweed, alder) among 1067 pediatric patients with allergic diseases was investigated. OAS in childhood differs from that in adulthood in some ways. One is that childhood OAS does not always accompany with pollinosis. The most frequent allergen in this study was kiwi fruit followed by tomato, orange and melon. The sensitization rate against alder was equivalent as that against orchard grass and short ragweed, but less than that against Japanese cedar. The study concludes that Childhood OAS may have different mechanisms from adulthood OAS which almost always accompanies with pollinosis or latex allergy. (Sugii 2006 ref.16084 3)

Sugii K, Tachimoto H, Syukuya A, Suzuki M, Ebisawa M. Association between childhood oral allergy syndrome and sensitization against four major pollens (Japanese cedar, orchard grass, short ragweed, alder). [Japanese] Arerugi 2006 Nov;55(11):1400-1408

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Atopy patch testing with Japanese cedar pollen extract has been used to investigate patients with atopic dermatitis whose condition is exacerbated by contact with Japanese cedar pollen. Comparative atopy patch testing, scratch tests, and assays for total IgE and specific IgE were performed in 74 patients with atopic dermatitis, 5 patients with Japanese cedar pollinosis and 15 control subjects. Twenty-two of the 74 patients (30%) had a history of exacerbation every spring after contact with Japanese cedar. Of these patients 68% showed a positive reaction to Japanese cedar pollen extract, as did 21% of patients with atopic dermatitis without a history of exacerbation by Japanese cedar pollen, 20% of patients with Japanese cedar pollinosis without eruption and 7% of control subjects. In conclusion, atopy patch testing with Japanese cedar pollen extract is a useful method for investigating trigger factors for eczematous skin lesions in a subgroup of patients with atopic dermatitis. (Yokozeki 2006 ref.22148 7)

Yokozeki H, Takayama K, Katayama I, Nishioka K. Japanese cedar pollen as an exacerbation factor in atopic dermatitis: results of atopy patch testing and histological examination. Acta Derm Venereol 2006;86(2):148-51.

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Approximately 16.2% of the Japanese population suffer from cedar pollinosis, with various manifestations such as ophthalmic, laryngo-pharyngeal and skin symptoms in addition to nasal symptoms. Purified cedar pollen allergen Cry j1 was instilled in the left eye of 9 patients with Japanese cedar pollinosis who had no nasal or ocular symptoms. Allergen provoked not only ocular symptoms but also nasal symptoms in 77.8% of patients. Symptoms were itching and hyperemia of the palpebral conjunctiva, and itching lasted for more than 5 hours. (Dake 2006 ref.22146 0)

Dake Y, Enomoto T, Cheng L, Enomoto K, Shibano A, Ikeda H, Yoda S, Yajin S, Sakota T, Yamanishi E. Effect of antihistamine eye drops on the conjunctival provocation test with Japanese cedar pollen allergen. Allergol Int 2006 Dec;55(4):373-8.

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This study, using meta-regression analysis on population-based surveys in Japan, concludes that the prevalence of Japanese cedar pollinosis among adolescents was predicted to be 28.7% in metropolitan areas and 24.5% in the general population in urban areas in the year 2004, derived from the estimated sensitization rate and the relationship between sensitization rate and prevalence. The prevalence of Japanese cedar pollinosis increased 2.6-fold between 1980 and 2000, and the prevalence differed considerably according to age and degree of urbanization. (Kaneko 2005 ref.11414 7)

Kaneko Y, Motohashi Y, Nakamura H, Endo T, Eboshida A. Increasing prevalence of Japanese cedar pollinosis: a meta-regression analysis. Int Arch Allergy Immunol 2005 Mar 2;136(4):365-371

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In Japan, many patients with pollinosis have specific IgE to both pollens of Japanese cypress and Japanese cedar. The sequences between Cha o 1 and Cry j 1, the major allergens of Japanese cypress and Japanese cedar pollens, respectively, are 80% identical. The presence of both T cells reactive to T cell epitopes common to Cha o 1 and Cry j 1 and T cells specific to T cell epitopes unique to Cha o 1 in patients with pollinosis contributes to prolonged symptoms after the cedar pollen season in March and the following cypress pollen season in April. (Sone 2005 ref.11720 5)

Sone T, Dairiki K, Morikubo K, Shimizu K, Tsunoo H, Mori T, Kino K. Identification of human T cell epitopes in Japanese cypress pollen allergen, Cha o 1, elucidates the intrinsic mechanism of cross-allergenicity between Cha o 1 and Cry j 1, the major allergen of Japanese cedar pollen, at the T cell level. Clin Exp Allergy 2005;35(5):664-71.

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Serum samples from 88 patients about 15 years ago (past group) and those from 91 current patients (present group) were randomly selected, and their Japanese Cedar (JC) specific IgE were measured. Sensitivity rate (class 2 or more) for JC of the present group was 65.9%, which was significantly higher than that of the past group, which was 46.6%. However, there was no significant difference between these two groups for children aged 6 or younger. For children aged 7 or older, the sensitivity rate of the present group was significantly higher than that of the past group. (Kusunoki 2004 ref.11088 7)

Kusunoki T, Miyanomae T, Inoue Y, Itoh M, Yoshioka T, Okafuji I, Nishikomori R, Heike T, Nakahata T. Changes in Japanese cedar sensitization rates of Japanese allergic children during the last 15 years. [Japanese] Arerugi 2004;53(10):1066-70.

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Serum samples from 88 patients about 15 years ago were compared with those from 91 randomly selected current patients. Sensitivity rate (class 2 or more) for Japanese cedar of the present group was 65.9%, which was significantly higher than that of the past group, which was 46.6%. However, there was no significant difference between these two groups for children aged 6 or younger. For children aged 7 or older, the sensitivity rate of the present group was significantly higher than that of the past group. The authors conclude that protection against Japanese cedar sensitization, especially during early childhood, should be given serious attention. (Incorvaia 2004 ref.11086 5)

Incorvaia C, Senna G, Mauro M, Bonadonna P, Marconi I, Asero R, Nitti F. Prevalence of allergic reactions to Hymenoptera stings in northern Italy. Allergie et immunologie 2004;36(10):372-4.

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These results suggest that Japanese cedar pollens play an important role in the aggravation of infantile AD in spring by inducing IL-5 production. (Kimura 2004 ref.22153 5)

Kimura M, Obi M, Saito M. Japanese cedar-pollen-specific IL-5 production in infants with atopic dermatitis. Int Arch Allergy Immunol 2004 Dec;135(4):343-7.

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These results suggest that the incidence of sinusitis in patients with Japanese cedar pollinosis tended to increase with exposure to extensive pollen dispersion and to be suppressed by initial treatment. (Hama 2002 ref.22160 7)

Hama T, Miyazaki M, Dejima K, Hisa Y, Fujieda S, Saito H, Imanaka M, Kawata R, Takenaka H. Clinical study of the paranasal sinuses of patients with Japanese Cedar pollinosis. [Japanese] Nippon Jibiinkoka Gakkai Kaiho 2002 Oct;105(10):1078-86.

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Japanese cedar pollinosis is a risk factor for bronchial asthma in Japanese adult asthmatics. (Ueno 2002 ref.22164 8)

Ueno K, Minoguchi K, Kohno Y, Oda N, Wada K, Miyamoto M, Yokoe T, Hashimoto T, Minoguchi H, Miyamoto M, Yokoe T, Hashimoto T, Minoguchi H, Tanaka A, Kokubu F, Adachi M. Japanese cedar pollinosis is a risk factor for bronchial asthma in Japanese adult asthmatics. [Japanese] Arerugi 2002 Jul;51(7):565-70.

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Skin specific IgE
Serum specific IgE

Of 934 patients born and raised in an area (Matsusaka, Japan) with nose and/or throat allergies, 35.2% had Japanese cedar pollen-specific immunoglobulin E in their serum, and 23.2% for cypress pollen. (Yamagiwa 2002 ref.7844 4)

Yamagiwa M, Hattori R, Ito Y, Yamamoto S, Kanba M, Tasaki T, Ueda K, Nishizumi T. Birch-pollen sensitization in an area without atmospheric birch pollens. Auris Nasus Larynx 2002;29(3):261-6

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Japanese cedar pollinosis is an important allergic rhinoconjunctivitis in Japan in spring. The relationship between the amount of pollen in the air and the prevalence of the disease and sensitization to Japanese cedar pollen was investigated. Specific IgE to Japanese cedar pollen (JCP-IgE) was determined and rhinoconjunctival symptoms surveyed. Prevalence rates of Japanese cedar pollinosis were 13.8-22.9%. Prevalence rates of being JCP-IgE >or=1.5 IU/ml were 39.0-50.1%, and those of being JCP-IgE >or=15.01 IU/ml were 11.4-23.2%. All prevalence rates were significantly related to the amount of pollen in the air. (Ozasa 2002 ref.5989 7)

Ozasa K, Dejima K, Takenaka H. Prevalence of Japanese Cedar Pollinosis among Schoolchildren in Japan. Int Arch Allergy Immunol 2002;128(2):165-7

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The prevalence and clinical characteristics of Japanese cedar pollinosis was investigated by questionnaire in 50,086 Japanese schoolchildren. Sensitisation to this allergen was 5.2%. The prevalence was higher in older children, and in those born in autumn and winter. Prevalence of CP in southern urban area was significantly higher (p < 0.001) than that in northern rural area. Among children with Atopic Dermatitis, there was statistically significant correlation between the severity of AD and the presence of Cedar Pollen (CP), i.e. those with CP tended to have more severe AD symptoms. On the other hand, the severity of asthma was not affected by the presence of CP (p = 0.323). (Kusunoki 2002 ref.5335 5)

Kusunoki T, Korematsu S, Nakahata T, Hosoi S. Cedar pollinosis in Japanese schoolchildren: results from a large questionnaire-based survey. [Japanese] Arerugi 2002;51(1):15-9

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The Japanese cedar pollen (JCP) is a major allergen with respect to pollinosis in Japan. The most common sensitizing allergens in this Korean urban and rural population in order of decreasing frequency were Dermatophagoides pteronyssinus (26.6%), Dermatoplagoides farinae (22.7%), citrus red mite (CRM) (14.2%), cockroach (11.3%), and Japanese cedar pollen (9.7%) among the rural children, but the sensitization rates to CRM and Japanese cedar pollen were 1.3% and 0.2% among the control children, respectively. (Lee 2001 ref.4228 3)

Lee MH, Kim YK, Min KU, Lee BJ, Bahn JW, Son JW, Cho SH, Park HS, Koh YY, Kim YY. Differences in sensitization rates to outdoor aeroallergens, especially citrus red mite (Panonychus citri), between urban and rural children. Ann Allergy Asthma Immunol 2001;86(6):691-5

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Oral allergy syndrome induced by spices with systemic symptoms - also with OAS induced by fruits and birch, alder and Japanese cedar pollinosis. (Taniguchi 2001 ref.9326 2)

Taniguchi H, Nishizawa A, Sasaki Y, Shono M. Oral allergy syndrome (OAS) induced by spices with systemic symptoms--also with OAS induced by fruits and birch, aler and Japanese cedar pollinosis. [Japanese] Arerugi 2001;50(1):29-31

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In 76 Japanese children under 6 years old, this study showed that the percentage of positive CAP-RAST to Japanese cedar pollen was 27.6%. These children had symptoms of asthma and atopic dermatitis. The youngest child who has been sensitized to pollen was 1-year 8-month-old boy. Of a further 27 children with Japanese cedar pollinosis attending the Otorhinolaryngology clinic, the majority complained of rhinorrhea and/or eye symptoms and some of them complained cough, snoring, or epistaxis. About 40% were sensitized to Japanese cedar and/or cupressaceae pollen alone, 60% were also sensitized to house dust mite. (Masuda 2000 ref.4486 5)

Masuda S, Terada A, Fujisawa T, Iguchi K. Japanese cedar pollinosis in infants in the allergy clinic. [Japanese] Arerugi 2000;49(12):1138-1145

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Asthma, hay fever and conjunctivitis. Laryngeal symptoms. (Naito 1999 ref.6129 0)

Naito K, Iwata S, Yokoyama N. Laryngeal symptoms in patients exposed to Japanese cedar pollen: allergic reactions and environmental pollution. [Letter] Eur Arch Otorhinolaryngol 1999;256(4):209-11

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This 1996 study recorded that the prevalence rate of allergy to Japanese cedar pollen in Tokyo was 25.7% in Akiruno city, 21.1% in Chofu city, and 17.7% in Ota The prevalence was highest in the age group of 30 to 44. (Nishihata 1999 ref.4500 6)

Nishihata S, Inouye S, Saiga T, Sahashi N, Suzuki S, Murayama K, et al. Prevalence rate of allergy to Japanese cedar pollen in Tokyo--from field investigation in 1996 by Tokyo Japanese Cedar Pollen Allergy Measurements and Review Committee. [Japanese] Arerugi 1999;48(6):597-604

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In this study, 48.5% of 97 patients with atopic dermatitis showed aggravation of dermatitis during the pollination season and 85% of them had Japanese cedar pollinosis, whereas only 44% of AD patients without the aggravation had the pollinosis. The levels of specific IgE antibodies to both allergens in the group with the pollinosis were significantly higher than in the group without the pollinosis. This study suggests that some other factors, e.g. Japanese cedar pollen -specific T cells, might play an important roll in addition to the Japanese cedar pollen -specific IgE. (Aihara 1999 ref.4496 0)

Aihara M, Takahashi S, Oosuna I, Yasueda H, Tsubaki K, Ikezawa Z. A study of aggravation of atopic dermatitis during Japanese cedar pollen season--correlation with grades of dermatitis on face and Cry j 1 specific IgE. [Japanese] Arerugi 1999;48(10):1172-1179

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In this study, 1321 individuals who were more than 16 years of age and who live in Wakayama Prefecture, had specific IgE antibodies to Japanese cedar pollen measured. The results showed a positive sera class 2 or higher in 30.9%. This was higher in males and highest in the 20-29 years old group. Compared to previous studies, the authors conclude that the incidence of Japanese cedar pollinosis has been increasing each year in Japan. (Enomoto 1999 ref.4495 3)

Enomoto T, Sakoda T, Dake Y, Shibano A, Saitoh Y, Takahashi M, et al. The positivity rate of specific IgE antibody to Japanese cedar pollen in Wakayama Prefecture. [Japanese] Nippon Jibiinkoka Gakkai Kaiho 1999;102(12):1311-1317

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The positive frequencies of Japanese cypress and Japanese cedar in 267 patients were 50.1% and 74.7%, respectively. (Ito 1995 ref.4513 2)

Ito H, Nishimura J, Suzuki M, Mamiya S, Sato K, Takagi I, Baba S. Specific IgE to Japanese cypress (Chamaecyparis obtusa) in patients with nasal allergy. Ann Allergy Asthma Immunol 1995;74(4):299-303

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Cry j I was still detected in house dust collected two weeks after airborne Japanese cedar pollen had disappeared. Thus some symptoms of Japanese cedar pollinosis patients after Japanese cedar pollen disappeared from the air may be caused by pollen which had attached to clothes and been brought indoors. (Takahashi 1994 ref.4521 2)

Takahashi Y, Miyazawa H, Sakaguchi M, Inouye S, Katagiri S, et al. Protracted (lasting) presence of Japanese cedar pollen allergen (Cry j I) in house dust. [Japanese] Arerugi 1994;43(2 Pt 1):97-100


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