Patch test of eczema and dermatitis: An analysis of 669 cases

Objective To study the contact allergens in patients with chronic eczema and dermatitis and their characteristics. Methods Patch test was performed to detect contact allergens in 669 patients with chronic eczema and dermatitis. Results Of the 669 patients with chronic eczema and dermatitis,312 were positive for patch test.Of these 312 patients,164,78,44,19 and 7 were positive for 1,2,3,4 and over 5 allergens,respectively.The positive rate to nickel sulfate was the highest（17.19%）,followed by cobalt chloride,potassium dichromate,aromatic mixture,colophane,parabens,formaldehyde and paraphenylenediamine. Conclusion Nickel sulfate,cobalt chloride,potassium dichromate,and aromatic mixture are the important contact allergens for eczema and dermatitis in our area.