title: A Case of Recurrent Urticaria Due to Formaldehyde Release from Root-Canal Disinfectant.
abstract: Although formaldehyde is well known to cause type 4 hypersensitivity, immunoglobulin E (IgE)-mediated hypersensitivity to formaldehyde is rare. Here, we report a case of recurrent generalized urticaria after endodontic treatment using a para-formaldehyde (PFA)-containing root canal sealant and present a review of previous studies describing cases of immediate hypersensitivity reactions to formaldehyde. A 50-year-old man visited our allergy clinic for recurrent generalized urticaria several hours after endodontic treatment. Prick tests to latex, lidocaine, and formaldehyde showed negative reactions. However, swelling and redness at the prick site continued for several days. The level of formaldehyde-specific IgE was high (class 4). Thus, the patient was deemed to have experienced an IgE-mediated hypersensitivity reaction caused by the PFA used in the root canal disinfectant. Accordingly, we suggest that physicians should pay attention to type I hypersensitivity reactions to root canal disinfectants, even if the symptoms occur several hours after exposure.
authors.affiliation: Department of Internal Medicine, Inje University Haeundae Paik Hospital, Busan, Korea.
authors.forename: Ji Hoon
authors.initials: JH
authors.lastname: Jang
authors.affiliation: Department of Internal Medicine, Inje University Haeundae Paik Hospital, Busan, Korea.
authors.forename: Seung Hyun
authors.initials: SH
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Inje University Haeundae Paik Hospital, Busan, Korea.
authors.forename: Hang Jea
authors.initials: HJ
authors.lastname: Jang
authors.affiliation: Department of Internal Medicine, Inje University Haeundae Paik Hospital, Busan, Korea.
authors.forename: Sung Geun
authors.initials: SG
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Inje University Haeundae Paik Hospital, Busan, Korea.
authors.forename: Jin Han
authors.initials: JH
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Inje University Ilsan Paik Hospital, Ilsan, Korea.
authors.forename: Jae Won
authors.initials: JW
authors.lastname: Jeong
authors.affiliation: Department of Internal Medicine, Inje University Haeundae Paik Hospital, Busan, Korea. chansun@paik.ac.kr.
authors.forename: Chan Sun
authors.initials: CS
authors.lastname: Park
mesh_terms: D004202:Disinfectants / Q000009:adverse effects*; D005557:Formaldehyde / Q000009:adverse effects*; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000139:chemically induced*; D007073:Immunoglobulin E / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D012008:Recurrence; D012882:Skin Tests; D013997:Time Factors; D014581:Urticaria / Q000139:chemically induced* / Q000175:diagnosis; D015035:Zinc Oxide-Eugenol Cement / Q000737:chemistry*
chemical_list: D004202:Disinfectants; D015035:Zinc Oxide-Eugenol Cement; C112894:canals sealer; D005557:Formaldehyde; D007073:Immunoglobulin E
keywords: Formaldehyde; type 1 hypersensitivity; urticaria