Celery allergy confirmed by double-blind, placebo-controlled food challenge: a clinical study in 32 subjects with a history of adverse reactions to celery root.
BACKGROUND
Celery root is a frequent cause of food allergy in pollen-sensitized patients. Because of problems in blinding challenges with fresh vegetables and the risk of anaphylactic reactions, no double-blind, placebo-controlled, food challenges (DBPCFCs) with celery have been published so far.


OBJECTIVE
The aim of the study was to confirm the clinical relevance of celery as a food allergen by DBPCFCs and to evaluate current diagnostic procedures in patients with true allergy.


METHODS
DBPCFCs were performed in 32 patients with a history of an allergic reaction to celery. The patients underwent skin prick tests (SPTs) with celery extracts, crude celery, and different pollen extracts. Specific IgE for celery was determined by using the CAP method.


RESULTS
Twenty-two of 32 patients had a positive DBPCFC result. Two patients reacted to placebo, and 8 patients did not respond to the challenge. Of the nonresponders, 4 reacted to an open provocation with celery. The sensitivity of CAP determination for specific IgE (> or =0.7 kU/L) to celery in patients with a positive DBPCFC result was 73%, 48% to 86% for SPTs (> or =3 mm) with commercial extracts, and 96% for prick-to-prick tests with crude celery. The positive predictive value of the SPT and CAP tests was between 87% and 96%, whereas the specificity and negative predictive values were poor.


CONCLUSIONS
This study confirms the importance of celery as a food allergen for use in DBPCFCs. The SPT and CAP methods proved to be reliable for the diagnosis of a relevant allergy to celery in regard to sensitivity and positive predictive value but not to specificity and negative predictive value.
Allergy Unit, Department of Dermatology, University Hospital, Zürich, Switzerland.
B K
BK
Ballmer-Weber
S
S
Vieths
D
D
Lüttkopf
P
P
Heuschmann
B
B
Wüthrich
D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000276:immunology; D052179:Antigens, Plant; D019661:Apiaceae / Q000009:adverse effects*; D004311:Double-Blind Method; D005260:Female; D005512:Food Hypersensitivity / Q000175:diagnosis / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010940:Plant Proteins / Q000276:immunology; D011058:Pollen / Q000276:immunology; D012882:Skin Tests
D000485:Allergens; D052179:Antigens, Plant; C096695:Api g 1 protein, Apium graveolens; D010940:Plant Proteins