Significance of Patch Test in Contact Dermatitis

Abstract

Contact dermatitis is a common condition. This allergic reaction of the skin is mediated by delayed hypersensitivity and accurs to a substance which comes in contact with the surface of the skin. Patch test is a very simple technique and helps in confirming the actual cause of the disease. Our study included randomly selected 36 known cases of contact dermatitis recruited from department of Dermatology Mayo Hospital Lahore who were patch tested with allergens of European standard series. Out of 36 patients, 19 presented a positive patch test and in 17 patients the patch test was negative. 11 patients (60%) showed sensitivity to 5% nickel sulphate, 4 patients (20%) presented a hypersensitive patch test to 5% nicked sulphate and 0.5% potassium dichromate simultaneously. One patient had sensitivity to 1% formaldehyde while 3 patients (16%) showed hypersensitivity to 8% fragrance mix. Out of 17 patients with negative patch test results 14 patients (82%) reported sensitivity to sunlight and their dermatitis aggravated and worsened in summers. 3 patients (18%) gave no history of sunlight sensitivity. In the light of our results we advocate patch test performance in every patient of contact dermatitis in order to prevent further exposures of the patients to causative agent.