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<article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ali="http://www.niso.org/schemas/ali/1.0/" article-type="other" dtd-version="1.2" xml:lang="en"><front><journal-meta><journal-id journal-id-type="publisher-id">Russian Journal of Allergy</journal-id><journal-title-group><journal-title xml:lang="en">Russian Journal of Allergy</journal-title><trans-title-group xml:lang="ru"><trans-title>Российский Аллергологический Журнал</trans-title></trans-title-group></journal-title-group><issn publication-format="print">1810-8830</issn><issn publication-format="electronic">2686-682X</issn><publisher><publisher-name xml:lang="en">Publishing House ABV Press</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="publisher-id">17103</article-id><article-id pub-id-type="doi">10.36691/RJA17103</article-id><article-categories><subj-group subj-group-type="toc-heading" xml:lang="en"><subject>Case reports</subject></subj-group><subj-group subj-group-type="toc-heading" xml:lang="ru"><subject>Клинические случаи</subject></subj-group><subj-group subj-group-type="article-type"><subject></subject></subj-group></article-categories><title-group><article-title xml:lang="en">Drug allergy to folic acid - myth or reality?</article-title><trans-title-group xml:lang="ru"><trans-title>Лекарственная аллергия на фолиевую кислоту – миф или реальность?</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0009-0009-1349-7187</contrib-id><contrib-id contrib-id-type="spin">8867-9448</contrib-id><name-alternatives><name xml:lang="en"><surname>Klimanova</surname><given-names>Yulia М.</given-names></name><name xml:lang="ru"><surname>Климанова</surname><given-names>Юлия Михайловна</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><email>ulklim5@gmail.com</email><xref ref-type="aff" rid="aff1"/></contrib><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0002-1606-205X</contrib-id><contrib-id contrib-id-type="spin">2063-7973</contrib-id><name-alternatives><name xml:lang="en"><surname>Latysheva</surname><given-names>Elena A.</given-names></name><name xml:lang="ru"><surname>Латышева</surname><given-names>Елена Александровна</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><bio xml:lang="en"><p>Dr. Sci. (Medicine)</p></bio><bio xml:lang="ru"><p>д-р мед. наук</p></bio><email>ealat@mail.ru</email><xref ref-type="aff" rid="aff1"/></contrib><contrib contrib-type="author"><contrib-id contrib-id-type="orcid">https://orcid.org/0000-0001-8491-195X</contrib-id><contrib-id contrib-id-type="spin">4684-3112</contrib-id><name-alternatives><name xml:lang="en"><surname>Myasnikova</surname><given-names>Tatiana N.</given-names></name><name xml:lang="ru"><surname>Мясникова</surname><given-names>Татьяна Николаевна</given-names></name></name-alternatives><address><country country="RU">Russian Federation</country></address><bio xml:lang="en"><p>MD, Cand. Sci. (Med.)</p></bio><bio xml:lang="ru"><p>канд. мед. наук</p></bio><email>t_miasnikova@mail.ru</email><xref ref-type="aff" rid="aff1"/></contrib></contrib-group><aff-alternatives id="aff1"><aff><institution xml:lang="en">National Research Center — Institute of Immunology Federal Medical-Biological Agency of Russia</institution></aff><aff><institution xml:lang="ru">Государственный научный центр «Институт иммунологии»</institution></aff></aff-alternatives><pub-date date-type="preprint" iso-8601-date="2026-03-04" publication-format="electronic"><day>04</day><month>03</month><year>2026</year></pub-date><volume>23</volume><issue>2</issue><issue-title xml:lang="ru"/><history><date date-type="received" iso-8601-date="2025-12-16"><day>16</day><month>12</month><year>2025</year></date><date date-type="accepted" iso-8601-date="2026-02-27"><day>27</day><month>02</month><year>2026</year></date></history><permissions><copyright-statement xml:lang="en">Copyright ©; , ABV-press</copyright-statement><copyright-statement xml:lang="ru">Copyright ©; , ИД "АБВ-пресс"</copyright-statement><copyright-holder xml:lang="en">ABV-press</copyright-holder><copyright-holder xml:lang="ru">ИД "АБВ-пресс"</copyright-holder><ali:free_to_read xmlns:ali="http://www.niso.org/schemas/ali/1.0/" start_date="2028-03-04"/><license><ali:license_ref xmlns:ali="http://www.niso.org/schemas/ali/1.0/">https://rusalljournal.ru/raj/user</ali:license_ref></license></permissions><self-uri xlink:href="https://rusalljournal.ru/raj/article/view/17103">https://rusalljournal.ru/raj/article/view/17103</self-uri><abstract xml:lang="en"><p>Drug allergy is one of the most interesting and complex issues that a doctor of any speciality may encounter in their practice. Accordingly, the study of drug allergies remains a pressing concern in modern medicine, including allergology, taking into account the increase in the number of pharmacological drugs available on the market, the duration of drug use in global practice, and the development of pharmacotherapy for various nosologies. The main causative drugs of drug hypersensitivity are antibiotics and NSAIDs. Folic acid is a rare trigger of drug allergy. Currently, there are only a few reported cases of drug allergy to folic acid. This article presents a clinical case of immediate-type drug allergy to folic acid, confirmed by in vivo testing.</p></abstract><trans-abstract xml:lang="ru"><p>Лекарственная аллергия – один из самых интересных и, в тоже время, сложных вопросов, с которым может столкнуться врач любой специальности в своей практике. Соответственно изучение лекарственной аллергии остается актуальной проблемой современной медицины, в том числе аллергологии, с учетом увеличения количества фармакологических препаратов на рынке, длительностью использования лекарственных средств в общемировой практике, а также развитие фармакотерапии различных нозологий. Основными причинно-значимыми лекарственными препаратами лекарственной гиперчувствительности являются антибиотики, НПВП. Фолиевая кислота относится к редким триггерам лекарственной аллергии. В настоящее время описаны единичные случаи лекарственной аллергии на фолиевую кислоту. В статье представлен клинический случай подтвержденной в ходе тестирования in vivo лекарственной аллергии немедленного типа на фолиевую кислоту.</p></trans-abstract><kwd-group xml:lang="en"><kwd>drug allergy</kwd><kwd>anaphylaxis</kwd><kwd>folic acid</kwd><kwd>Vitamin B9</kwd><kwd>drug provocation testing</kwd></kwd-group><kwd-group xml:lang="ru"><kwd>лекарственная аллергия</kwd><kwd>анафилаксия</kwd><kwd>фолиевая кислота</kwd><kwd>витамин В9</kwd><kwd>тестирование с лекарственными препаратами</kwd></kwd-group><funding-group/></article-meta></front><body></body><back><ref-list><ref id="B1"><label>1.</label><citation-alternatives><mixed-citation xml:lang="en">1.	Khaitov R.M., Ilina N.I., eds. Allergology. Clinical Guidelines. Moscow: GEOTAR-Media; 2009:256</mixed-citation><mixed-citation xml:lang="ru">1.	Аллергология. Клинические рекомендации / Под ред. Р. М. Хаитова, Н.И. 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