The reliability and validity of a developed anxiety scale specific to primary focal hyperhidrosis symptoms.

Background: Patients with primary focal hyperhidrosis (hyperhidrosis) are known to have higher levels of anxiety induced by sweating than those who do not. However, in hyperhidrosis, no scale has been developed to measure anxiety specific to hyperhidrosis symptoms. Therefore, this study aimed to develop an anxiety scale specific to hyperhidrosis symptoms (ASSHS) and to verify its reliability and validity.

Methods: Based on previous studies on hyperhidrosis and a preliminary survey conducted with 26 university students who met the diagnostic criteria for hyperhidrosis, 40 items that adequately reflected anxiety specific to hyperhidrosis symptoms were obtained. A survey was done to examine the internal consistency and validity of the our developed ASSHS. In total, 1,207 participants (680 male and 527 female; mean age ± standard deviation 18.7 ± 0.9 years) were included. A second survey (re-survey) was conducted three weeks later to verify the reliability. It included 201 participants (85 male and 116 female; mean age ± standard deviation 18.6 ± 0.7 years). The survey items included (1) the diagnostic criteria for hyperhidrosis, (2) our anxiety scale developed for primary focal hyperhidrosis symptoms (ASSHS), (3) Hyperhidrosis Disease Severity Scale (HDSS), (4) State-Trait Anxiety Inventory (STAI), (5) Hospital Anxiety and Depression Scale (HADS), (6) Dermatology Life Quality Index (DLQI), and (7) presence of anxiety induced by sweating.

Results: The results of the factor analysis revealed 10 items with one factor, "anxiety specific to hyperhidrosis symptoms." The alpha coefficient of the ASSHS was α = 0.94. The correlation coefficient between the scores at re-test was r = 0.75. A moderate positive correlation was found between the ASSHS, HDSS (r = 0.53), and anxiety induced by sweating (r = 0.47) (all p < 0.001). Additionally, participants with hyperhidrosis symptoms had significantly higher ASSHS scores than did those without hyperhidrosis symptoms (p < 0.001). Those with mild/moderate hyperhidrosis and those with severe hyperhidrosis had significantly higher the ASSHS scores than did those without hyperhidrosis (p < 0.001).

Conclusions: This scale has sufficient reliability and validity as an instrument to measure anxiety specific to hyperhidrosis symptoms.