The reactivity of the back revisited. Are there differences in reactivity in different parts of the back?
BACKGROUND
In the contact dermatitis literature, it is regularly stated that the patch test reactivity on various areas of the back differs, which might have a large impact on the reproducibility of patch testing.


OBJECTIVE
To investigate the reproducibility of patch testing on the upper back with regard to the left as opposed to the right side, and the medial as opposed to the lateral part of the upper back. The reproducibility over time and with regard to the reactivity pattern was also investigated.


METHODS
Thirty-one subjects with contact allergy to the metals gold (n = 19) or nickel (n = 12) were patch tested with serial dilutions, in triplicate applications, on different locations on the upper back. The Friedman test was used for statistical calculations.


RESULTS
No significant differences in the reactivity of the back were found. In all gold-allergic patients and 11 of 12 nickel-allergic patients, the allergy could be reproduced with regard to previous patch testing, but the degree of reactivity differed.


CONCLUSIONS
When a high level of standardization of the patch test technique with the same test system was used, there were no differences in patch test reactions and sites of application on the upper back.
Department of Occupational and Environmental Dermatology, Skåne University Hospital, Lund University, 205 02, Malmö, Sweden.
Ann-Kristin
http://orcid.org/0000-0002-7764-6673
AK
Björk
Department of Occupational and Environmental Dermatology, Skåne University Hospital, Lund University, 205 02, Malmö, Sweden.
Magnus
M
Bruze
Department of Occupational and Environmental Dermatology, Skåne University Hospital, Lund University, 205 02, Malmö, Sweden.
Malin
M
Engfeldt
R&D Centre Skåne, Skåne University Hospital, 22185, Lund, Sweden.
Christel
C
Nielsen
Department of Occupational and Environmental Dermatology, Skåne University Hospital, Lund University, 205 02, Malmö, Sweden.
Cecilia
C
Svedman
D000485:Allergens / Q000009:adverse effects; D001415:Back; D017449:Dermatitis, Allergic Contact / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D006046:Gold / Q000009:adverse effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D009532:Nickel / Q000009:adverse effects; D010328:Patch Tests / Q000379:methods*; D015203:Reproducibility of Results
D000485:Allergens; D006046:Gold; D009532:Nickel
anatomical site; angry back; contact allergy; excited skin syndrome; patch test; reactivity; reproducibility; serial dilution