The Illness Intrusiveness Rating Scale: a measure of severity in individuals with hyperhidrosis.
OBJECTIVE: We estimated the reliability and validity of the Illness Intrusiveness Ratings Scale (IIRS) in hyperhidrosis, using an electronic mail form of administration. METHODS: Recent contributors to an electronic mail discussion group on hyperhidrosis responded to the IIRS, questions about surgical history, items designed to assess severity, and demographic questions, on two occasions four weeks apart. A variety of hypotheses regarding the relationships between these variables were constructed a priori. RESULTS: Sixty-eight people replied on two occasions. Internal consistency was high (Cronbach's alpha 0.88), as was test-retest reliability (kappa 0.89). The total IIRS score correlated with a global severity question (0.61; p < 0.001). Total IIRS score was lower in participants who had previously had surgery for hyperhidrosis, compared with those who had not (47 vs. 36; p = 0.02), and changed dramatically in the direction of diminished severity in four patients who underwent surgery during the course of the study (54 vs. 17; p = 0.01). Weak-to-moderate correlations were observed between total score and use of topical preparations, use of medications, number of clothing changes during a day, and limitations in choice of wardrobe. CONCLUSIONS: The IIRS is both reliable and valid in the assessment of patients with hyperhidrosis. A novel form of administration does not appear to affect its properties.