Validation of new items for diagnosing primary hyperhidrosis and the prevalence of primary hyperhidrosis.

Background: The Multi-Specialty Working Group on the Recognition, Diagnosis, and Treatment of Primary Focal Hyperhidrosis developed evidence-based consensus criteria for diagnosing primary hyperhidrosis.

Objectives: To validate new questionnaire items for self-reported classification of primary hyperhidrosis based on the consensus criteria and to estimate the prevalence of primary hyperhidrosis.

Methods: This is a cross-sectional diagnostic accuracy study. Questionnaires containing the index tests and reference tests were distributed to blood donors at blood centers between June and December of 2021 in Region Zealand, Denmark. The index tests were the two questions 'Have you had troublesome sweating?' and 'Have you ever had troublesome sweating?', which were used to create six single-item algorithms for classifying primary hyperhidrosis. The reference test was the consensus criteria.

Results: Overall, 1,071 (95.9%) of 1,083 eligible blood donors completed the index tests. The reference test classified 59 participants as having primary hyperhidrosis and 980 as not having primary hyperhidrosis, generating a prevalence of 5.7% (95% confidence interval 4.4-7.3%). The algorithms with the highest combined sensitivity and specificity were algorithm 2 with a sensitivity of 0.94 (95% confidence interval 0.77-0.99) and a specificity of 0.94 (confidence interval 0.92-0.95), and algorithm 5 with a sensitivity of 0.94 (95% confidence interval 0.80-0.99) and a specificity of 0.92 (confidence interval 0.90-0.94).

Conclusions: With high diagnostic accuracy, these items allow for the identification of individuals with and without primary hyperhidrosis, which may prove useful in epidemiological research. Validation in the general population is warranted.