Therapeutic effectiveness of botulinum toxin type A based on severity of palmar hyperhidrosis

A dose of 60 units (U) of botulinum toxin type A (BT-A) has been confirmed to have efficacy for patients with palmoplantar hyperhidrosis. However, the effectiveness of this dose is limited in severe cases defined as sweat production of 2 mg/cm(2) per min or more (measured by the ventilated capsule method) and a Hyperhidrosis Disease Severity Scale (HDSS) grade of 3 or 4. An increased dose of 90 U of BT-A was found to reduce sweating for approximately 7 months. In a comparison of patients with sweat production of more than 2.5 mg/cm(2) per min and an HDSS grade of 4 and patients with sweat production of 2.5 mg/cm(2) per min or less and an HDSS grade of 3, there was no difference in the reduction of sweat production at 5 months, but the duration of the reduced sweating was shorter for the former group. This suggests that there are limits to the efficacy of BT-A for severe forms of the disease with sweat production of more than 2.5 mg/cm(2) per mL.