Comparison of the use of standardized diagnostic criteria and intuitive clinical diagnosis in the diagnosis of common viral warts (verrucae vulgaris).

OBJECTIVE To assess the diagnostic value of standardized diagnostic criteria compared with the clinical intuitive diagnosis for verrucae vulgaris. DESIGN A blind comparison with cross-over of experienced dermatologists using either intuitive clinical diagnosis or else recording the presence of standardized diagnostic criteria in verrucae vulgaris. SETTING Clinical outpatient department in a major teaching hospital. PATIENTS Fifteen patients aged 6 to 60 years with 21 verrucae vulgaris and 24 control lesions. INTERVENTION Dermatologists examined the lesions and recorded either the diagnosis by the usual clinical intuitive method or else whether standardized diagnostic criteria were present in the lesion of each patient. Each dermatologist did 1 only of the 2 methods for each lesion with the other doing the alternative method for the same lesion, neither of them having previously been aware of any of the diagnoses. MAIN OUTCOME MEASURE The sensitivity, specificity, and positive predictive, negative predictive, and relative values for each diagnostic approach were compared. RESULTS Use of intuitive clinical diagnosis resulted in 100% specificity, sensitivity, and positive predictive, negative predictive, and relative values for both the verrucae vulgaris and the control lesions. Recording the presence of the diagnostic criteria reduced to a varying extent all the parameters of diagnostic accuracy with site--fingers and hands, elbows, and knees--being the most efficacious of the criteria. CONCLUSIONS These data indicate that care is required in relying too much on standardized criteria as the basis for clinical diagnosis, even for a lesion as simple as a wart. They also reinforce the value of clinical experience obtained from repeated exposure to multiple variants of a disease in the traditional bedside teaching model.