Are patients better than the laboratory in assessing sweating? Validation study.

BACKGROUND: Primary focal hyperhidrosis is a hereditary condition characterized by excessive sweating affecting a variety of areas, including the palms. In most cases, the decision to treat a patient is based only on the patient's own description of the symptoms because laboratory tests have not been established in clinical practice. OBJECTIVE: To validate a subjective self-assessment scale for sweating in comparison with an objective method of quantifying evaporation from the skin surface. METHODS: We studied palmar sweating in 20 patients with primary focal hyperhidrosis and 20 age- and gender-matched controls. Four times in each subject, we obtained measurements of the evaporation in palms and the self-evaluation scale (SES) scores on a proportional scale from 0 (no sweating) to 10 (worst imaginable sweating). RESULTS: Good correlation was found between the SES score and evaporation assessment (R = .65). The SES score was easier to obtain and provided better diagnostic sensitivity and specificity. They leveled out at over 80% when a score of 3 was used as the threshold level; for evaporimetry, sensitivity equalled specificity at 70% at the threshold 90 mg -2h(-1). CONCLUSION: We confirm the usefulness of the SES in assessing palmar sweating and discuss the current restrictions in its use in clinical diagnosis. We propose that the scale can be added effortlessly to research or clinical protocols to provide the necessary validation in wider spectra of patients.