Seasonal and Other Factors Affecting Patch Testing Integrity in a Tropical Climate Country

Abstract

KUMPANGSIN T*, LIMPHOKA P*, SUKAKUL T**, BOONCHAI W*, BUNYAVAREE M*. SEASONAL AND OTHER FACTORS AFFECTING PATCH TESTING INTEGRITY IN A TROPICAL CLIMATE COUNTRY. THAI J DERMATOL 2021;37:1-9.

^*DEPARTMENT OF DERMATOLOGY, FACULTY OF MEDICINE SIRIRAJ HOSPITAL, MAHIDOL UNIVERSITY, BANGKOK, THAILAND.

**DEPARTMENT OF OCCUPATIONAL AND ENVIRONMENTAL DERMATOLOGY, LUND UNIVERSITY, SKÅNE UNIVERSITY HOSPITAL, MALMÖ, SWEDEN.

Background: Patch testing, the gold standard for allergic contact dermatitis diagnoses, is a multiple-visit procedure whose interpretation can be affected by several factors. While the patches need to remain in place undisturbed for 48 hours, certain factors may affect patch adhesion.

Objective: To establish the prevalence of imperfect chamber strip adhesion and identify the factors associated with patch test integrity.

Materials and Methods: This prospective study was performed between June 2018 and May 2019 at the Contact Dermatitis Clinic, Siriraj Hospital, Bangkok, Thailand. Patients undergoing patch testing as per standard guidelines were recruited. Details of meteorological factors (temperature and relative humidity) and patients’ characteristics were collected.

Results: In all, 420 patch-tested patients were enrolled. Imperfect strip adhesions were reported for 28.33% of the cohort. Being a student, heavy sweating, a history of water exposure on the patch, sleeping on one’s side, and testing in the rainy season were significantly associated with defective strip adhesion.

Conclusion: Patch-test-strip adhesion was significantly affected by patients’ characteristics and behaviours as well as whether the tests were performed in the rainy season. However, other meteorological factors (UV index, temperature and humidity) did not disturb patch-test-strip adhesion. Applying additional adhesive tape is recommended for patients at risk.