Patch photopatch test at Manipal

Abstract

Patch and photopatch testing was performed on 55 patients with history of photosensitivity using Scandanavian photo patch test antigens obtained from Chemotechnique Diagnostics AB Sweden.
The commonest reactions were seen to perfume mix 4 (21.0%), PABA 3 (15.78%), promethazine hydrochloride 3 (15.78%), chlorpromazine hydrochloride 3 (15.78%), balsam of peru 2 (10.52%), usnic acid, hexachlorophane, musk ambrette and 6 methyl coumarin showed 1 positive reaction each (5.26%) suggesting either phototoxicity or photo sensitization. Patch and photo patch test positive reaction suggesting allergic sensitisation was seen to balsam of peru 3 (23.0%) perfume mix 3 (23.0%) promethazine hydrochloride 2 (15.3%) and PABA, 6 methyl coumarin, tribromosalicylanilide, atranorin and wood mix showed positive reaction in one case each (7.69%).
We conclude that photoxic or photo allergic reaction is a problem in India and patch photo patch test should be performed in all cases of idiopathic light eruptions to rule out photo sensitisation and in cases where photo sensitivity of exogenous origin is suspected.