A Case of Recurrent Urticaria Due to Formaldehyde Release from Root-Canal Disinfectant

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.

Pathogenesis of allergic conjunctivitis and trends in its treatment

Allergic conjunctivitis is characterized by specific immunologic responses known as type 1 hypersensitivity, resulting in corneal and conjunctival inflammation. Histamine plays an important role in the pathophysiologic mechanism of allergic conjunctivitis. Five subtypes of allergic conjunctivitis have been defined according to specific signs and symptoms: seasonal allergic conjunctivitis, perennial allergic conjunctivitis, vernal keratoconjunctivitis, atopic keratoconjunctivitis and giant papillary conjunctivitis. Above all, avoidance of the offending antigen is the primary behavioral modification used to treat all types of allergic conjunctivitis. However, this may be difficult for practical reasons; therefore, a range of medical treatment options, such as topical antihistamines, mast cell stabilizers, non-steroidal anti-inflammatory drugs, and corticosteroids are prescribed in clinical practice.

Isolation of Human scFv Antibodies Specific for House Dust Mite Antigens from an Asthma Patient by Using a Phage Display Library

BACKGROUND: In order to characterize human antibodies with specificity for mite allergens at the molecular level, a scFv phage display library was constructed using peripheral blood mononuclear lymphocytes from an asthma patient allergic to mite as Ig gene sources. METHODS: Immunoglobulin VH and V gene fragments were obtained by polymerase chain reaction, and randomly combined in pCANTAB-5E vector. The resulting human scFv phage display library had 3 X 10(4) independent clones, and biopanning was performed with house dust mite extracts. RESULTS: Four scFv clones specific for house dust mite extract were isolated. Immunoblot assay showed that our clones reacted to 25 kDa and 50~60 kDa proteins with unknown identity in mite extracts. Sequence analysis indicated that two clones (b7 and c15) are identical, and all clones belong to human VH3 subgroup. On the other hand, light chain usage was different in that two clones (a2 and b7/c15) belonging to V kappa 4 subgroup, but a4 used V kappa 1 light chain gene. CONCLUSION: Our approach should facilitate provision of useful information on the antibody responses against allergens at the molecular level in humans.

A Case of Contact Urticaria from a Latex Glove Occurred to an Operationg Room Nurse

The prevalence of latex allergies has been on the increase along with the greater use of rubber products in daily life, medical, dental and occupational settings. Allergic reactions to latex can take two clinical forms of either contact dermatitis or immediate hypersensitivity reactions, which are provoked by the natural latex proteins or chemical additives used in the manufacturing process, respectively. A 25-year-old female, an operating room nurse, complained of recurrent pruritic erythematous wheals on both hands after the wearing of latex rubber gloves. The prick test and the usage Mlit't to the latex gloves were positive, and the RAST was class 3. To the best of our knowledge, is the first case report of contact urticaria from latex rubber gloves in Korean dermatologic literature.