Alfred M. Allen

Allergic Contact Hypersensitivity to Nickel, Neomycin, Ethylenediamine, and Benzocaine: Relationships Between Age, Sex, History of Exposure, and Reactivity to Standard Patch Tests and Use Tests in a General Population

A study population of 1,158 paid adult volunteers was obtained. Prior to patch testing, a history of previous exposure to four allergens also was obtained. Prevalence of positive reactions to patch tests was nickel, 5.8%; neomycin, 1.1%; ethylenediamine, 0.43%; and benzocaine, 0.17%. Nine percent of women reacted to nickel compared with 0.9% of men. There was a strong correlation of nickel sensitivity with a history of pierced ears, earlobe rash, and jewelry rash. Ten of 12 neomycin-positive subjects used neomycin for one week or longer on an inflammatory dermatosis, compared with six of 36 age-, race-, and sex-matched controls. By history, 85% were exposed to benzocaine, 48% to neomycin, and 15% to Mycolog (ethylenediamine). Of 127 patients referred to clinics for evaluation of contact dermatitis, 11% yielded positive tests to nickel, 6.3% to neomycin, 3.1% to ethylenediamine, and 1.6% to benzocaine. Data obtained from testing contact dermatitis patients are not applicable to the general population.

Epidemiology of Skin Infections: Strategies Behind Recent Advances

Epidemiologic information on skin infections has increased greatly in both quantity and quality during the past decade. Prior to that time, quality suffered from poor populations sampling procedures and quantity was limited to the results of a few small surveys. As likely as not, “epidemiologic” knowledge was based on highly biased convenience samples of patients attending a clinic. No matter how good the microbiology, the results were of limited value in establishing the epidemiology of infection.