Correlation of photopatch positivity with clinical profile in patients with photoallergic dermatitis

Abstract

Photopatch test (PPT) is designed to diagnose Photoallergic Contact Dermatitis (PACD) using specific dose and wavelength of irradiation. This study is a retrospective analysis of patients with photosensitivity who have undergone photopatch testing. To find the Correlation of photo patch positivity with clinical profile in patients with photoallergic dermatitis. Photo patch testing helps in determining the sensitizing potentials of commonly used day to day agents containing the allergen. Thirty-seven patients who had patch tested between July 2022and June 2023 were analyzed. The patch test antigens comprising 20 common photoallergens from Indian Standard Series were photopatch tested. Of all the patients tested the overall positivity rate was (67.56%). All patients had a characteristic clinical picture of photodermatitis for an variable duration. All patients were engaged in various occupations that involved working outdoors. The exacerbating factors were summer season in 15 (40.54%) patients, insecticides spraying in three (8.1%) and exposure to plant in ten (27%). History of contact with cement was present in six (16.21%) patients. The patients who showed positivity after irradiation was 5 (13.51 %), before and after irradiation was 7 (18.91%), and exacerbated grading after irradiation was 13 (35.13%). The commom allergen showing positivity were parthenium (29.72%), potassium dichromate (13.51%), PPD (10.81%). Apart from these allergens’ fragrance mix, paraben, neomycin sensitivity was also noted in few patients. Significant number of cases belongs to photodermatitis, thereby, finding the cause and the measures to alleviate the symptoms are paramount important. For proper diagnosis, photopatch test is essential and our study emphasis the same which can aid in appropriate management. Cosmetics, sunscreens and drugs like NSAID are found to be the emerging cause for PACD and photopatch series with relevence to above allergen is the need of the hour.