Wheat allergy: a double-blind, placebo-controlled study in adults.
BACKGROUND
Wheat is believed to be an uncommon cause of food allergy in adults; the number of studies that address IgE mediated wheat allergy in adults is all too few.


OBJECTIVE
Determine how many subjects with a history of wheat allergy have real allergy by double-blind, placebo-controlled food challenge; identify the symptoms manifested during the challenge; determine the lowest provocation dose; determine the performance characteristics of wheat skin prick test and specific IgE; identify subjects with real wheat allergy for potential immunoblotting studies.


METHODS
Patients underwent skin test with commercial wheat extract; specific wheat IgE was determined. Subjects were challenged with 25 g wheat. Subjects who were positive to raw wheat challenge underwent cooked wheat challenge.


RESULTS
Thirty-seven double-blind placebo-controlled wheat challenges were performed on 27 patients. A total of 13 of 27 (48%) patients had a positive result. Eleven subjects with positive raw wheat challenge underwent cooked wheat challenge: 10 were positive. The provocation dose range was 0.1 to 25 g. Twenty-seven percent of the subjects allergic to wheat had a provocation dose that was < or =1.6 g.


CONCLUSIONS
Wheat causes real food allergy in adults. More than a quarter of the patients allergic to wheat reacted to less than 1.6 g wheat. Specific IgE was more sensitive than skin test for wheat; however, specificity and predictive values were low for both tests. Thus, these tests should not be used to validate diagnosis of wheat allergy.
Scibilia
Joseph
J
Unit of Allergology and Clinical Immunology, Azienda Ospedaliera Niguarda Hospital, Milan, Italy.
Pastorello
Elide A
EA
Zisa
Giuliana
G
Ottolenghi
Anna
A
Bindslev-Jensen
Carsten
C
Pravettoni
Valerio
V
Scovena
Elena
E
Robino
Anna
A
Ortolani
Claudio
C
D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000008:administration & dosage / Q000009:adverse effects* / Q000276:immunology; D003718:Denmark; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007558:Italy; D008297:Male; D008875:Middle Aged; D010919:Placebos; D011237:Predictive Value of Tests; D012882:Skin Tests; D014908:Triticum / Q000009:adverse effects* / Q000276:immunology; D021182:Wheat Hypersensitivity / Q000175:diagnosis* / Q000503:physiopathology*
D000485:Allergens; D010919:Placebos; D007073:Immunoglobulin E