Clean rooms and itchy faces.

Seventy-one male employees whose working environment was a temperature and dust controlled low-humidity 'Clean Room' and 144 male employees working in a natural factory environment were compared by means of period percentage prevalences of occurrence, severity and frequency of subjective symptoms of facial dermatitis. Using a cross-sectional interviewer-administered questionnaire it was possible to assess the percentage prevalence of each of 3 facial dermatitis symptoms among both low humidity exposed and non-exposed workers. The two prevalences were compared by calculating a ratio (the percentage prevalence ratio or PPR) of the prevalence of symptoms in the exposed, to that in the non-exposed workforce. A confidence interval (CI) for the PPR was also calculated. For the symptom of itching, the PPR was 1.65 (CI 1.32-2.07) in favour of the study group, whilst for the symptoms of redness and urticaria the PPRs were 1.96 (CI 1.54-2.48) and 2.53 (CI 1.40-4.59) respectively. The occurrence of a greater prevalence of all symptoms in the low-humidity exposed workforce confirms the clinical and laboratory reports of previous workers. A comparison was also made between the two groups of workers of both the severity, and the frequency of occurrence of symptoms. Whilst there was no statistically significant difference between the exposed and non-exposed groups for prevalence of one symptom, among those who had experienced two symptoms there was a PPR of 2.43 (CI 1.37-4.30) between the two groups. Furthermore, among those workers who had experienced all 3 symptoms of facial dermatitis there was a PPR of 3.38 (CI 1.18-8.93) in favour of the low-humidity exposed workforce.(ABSTRACT TRUNCATED AT 250 WORDS)