Eczematous skin reaction to atopy patch testing with cockroach in patients with atopic dermatitis.
BACKGROUND
Aeroallergens from house dust mite (HDM) may be an important trigger in a subgroup of patients with atopic dermatitis (AD). HDM and cockroach (CR) contain cross-reactive allergens, such as tropomyosin.


OBJECTIVE
To investigate the diagnostic value of patch testing with an aeroallergen and the role of CR allergen and HDM allergen in persons with AD.


METHODS
We performed skin prick tests (SPT) with a panel of common aeroallergens and total serum immunoglobulin (Ig)E and specific IgE tests for CR and HDM on 23 patients with AD and 9 nonatopic control participants. Atopy patch tests (APT) were performed with CR and HDM extracts on clinically uninvolved skin on the back, and evaluated after 48 and 72 hours.


RESULTS
A positive APT reaction to CR was found in 10/23 (43%) patients with AD. No positive reactions were observed in the nonatopic control participants. Positive APT reactions for CR showed no significant correlation with SPT or specific IgE levels for this allergen. Twelve of the 23 (52%) patients with AD were also sensitized to HDM. There was no significant correlation between positive results for SPT, APT, and specific IgE to CR and HDM.


CONCLUSIONS
We demonstrate that CR allergens can induce positive patch test reactions in patients with AD. The absence of a significant correlation to SPT and specific IgE antibodies suggests that T-cell- and IgE-sensitization may be mediated by different allergens. There was no significant relationship between CR and HDM sensitivity, thus indicating no major cross-reactivity.
Michel
S
S
University Clinic for Rheumatology and Clinical Immunology/Allergology, Inselspital, University of Bern, Switzerland.
Yawalkar
N
N
Schnyder
B
B
Fischer
B
B
Helbling
A
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D000485:Allergens / Q000276:immunology*; D000818:Animals; D002648:Child; D003058:Cockroaches / Q000276:immunology*; D003429:Cross Reactions / Q000276:immunology; D003876:Dermatitis, Atopic / Q000175:diagnosis / Q000276:immunology*; D004485:Eczema / Q000175:diagnosis / Q000276:immunology*; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D008297:Male; D008875:Middle Aged; D010328:Patch Tests; D039981:Pyroglyphidae / Q000276:immunology*; D011795:Surveys and Questionnaires; D055815:Young Adult
D000485:Allergens; D007073:Immunoglobulin E