The assessment of irritation using clinical methods and questionnaires

Sensory irritant responses to chemical exposures are measured by a variety of methods; however, studies can be influenced from biases associated with study design and subject responses. This article reviews the different meth ods used to quantitate irritation. These methods primarily focus on eye and nasal mucosal irritation. Although methods to evaluate mouth, throat mucos al, and dermal irritation are also relevant, they are seldom used in actual practice, Measurements for eye irritation include tear film stability, epi thelial damage, foam formation, blinking frequency, tear flow, inflammation , and hyperemia. Methods for detecting nasal mucosa irritation include meas uring swelling of the nasal mucosa, peak airflows through the nose, acousti c rhinometry, and rhinostereometry, which measures thickness of the anterio r nasal turbinate. Questionnaires are useful for defining a set of symptoms in an attempt to characterize dose-response relationships from controlled exposure studies or field studies, to compare rates of events in field stud ies, or to screen for disease. However, it is important to consider careful ly the study design, goal of utilization, and constraints surrounding their application. Whichever method is used in medical surveillance or to evalua te effectiveness of industrial hygiene or engineering controls in preventin g irritation effects from chemical exposure, the sensitivity, specificity, and predictive value of the irritation measurements are important factors i n interpreting the results. This article reviews these various issues and o ffers some advice.