Delayed Patch-Test Reading After 5 Days: An Update From the Mayo Clinic Contact Dermatitis Group
Hafsa M Chaudhry1, Lisa A Drage, Rokea A El-Azhary
1From the *Mayo Clinic School of Medicine, Mayo Clinic College of Medicine and Science; and †Division of Clinical Dermatology, Mayo Clinic, Rochester, MN; ‡Department of Dermatology, Mayo Clinic, Jacksonville, FL; §Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN; and ∥Division of Clinical Dermatology, Mayo Clinic, Scottsdale, AZ.
Background:
Patch-test readings after day 5 have previously been used to identify delayed reactions to metals and topical antibiotics.
Objective:
The aims of this study were to identify allergens for which late readings (beyond day 5) would be most valuable and to compare our results with our previous study on delayed patch-test readings.
Methods:
This was a retrospective study of 298 patients who underwent metal and corticosteroid series patch testing from January 1, 2007, through December 31, 2013. Patch-test readings were conducted on days 3 and 5 and at least once sometime between days 7 and 14. All reactions were examined at each reading.
Conclusions:
These results were concordant with our previous findings that additional readings after day 7 are particularly useful for identifying reactions to metals (gold, cobalt, beryllium, palladium), specific preservatives (dodecyl gallate, propolis), and the topical antibiotic neomycin. New delayed reactions to bacitracin, p-phenylenediamine, and topical corticosteroids were not seen in this cohort.
Insights
Late patch-test readings after day 7 are valuable for identifying delayed allergic reactions to specific metals and preservatives. This study confirms their utility, especially for metals like gold and cobalt, and preservatives such as dodecyl gallate.
Area of Science:
- Dermatology
- Allergology
- Contact Dermatitis
Background:
- Delayed patch-test readings beyond day 5 have been used to detect reactions to metals and topical antibiotics.
- Previous research indicated the value of extended patch-test reading intervals.
Purpose of the Study:
- To determine which allergens benefit most from late patch-test readings (after day 5).
- To compare current findings on delayed patch-test reactions with prior studies.
Main Methods:
- A retrospective analysis of 298 patients undergoing metal and corticosteroid series patch testing.
- Patch tests were read on days 3, 5, and between days 7–14, with all reactions documented at each interval.
Main Results:
- Late readings (after day 7) were particularly useful for identifying reactions to metals (gold, cobalt, beryllium, palladium).
- Specific preservatives (dodecyl gallate, propolis) and the antibiotic neomycin also showed utility with late readings.
- No new delayed reactions were observed for bacitracin, p-phenylenediamine, or topical corticosteroids in this cohort.
Conclusions:
- Extended patch-test reading intervals are beneficial for detecting delayed hypersensitivity to certain metals and preservatives.
- The findings align with previous research, reinforcing the importance of late readings for specific allergens.
- Further investigation into delayed reactions to other substances may be warranted.
More Related Videos
07:26Conducting Maximal and Submaximal Endurance Exercise Testing to Measure Physiological and Biological Responses to Acute Exercise in Humans
Published on: October 17, 2018
11:10Antibody Binding Specificity for Kappa (Vκ) Light Chain-containing Human (IgM) Antibodies: Polysialic Acid (PSA) Attached to NCAM as a Case Study
Published on: June 29, 2016