Botulinum toxin type A should be PBS listed for treatment of palmar hyperhidrosis

To the Editor: Hyperhidrosis is uncontrollable, excessive sweating. Severe primary focal palmar hyperhidrosis is a significant disability. It interferes with many activities of daily living and induces social avoidance behaviours that can lead to symptoms of social anxiety disorder. Symptoms begin in childhood or around puberty and affect both sexes equally.1

There are a number of treatments for palmar hyperhidrosis, which have varying degrees of success. Medical treatments are temporary and include topical aluminium chloride and tap water iontophoresis. Surgical sympathectomy is a longer-term option with intrinsic risks.

Botulinum toxin type A (BTX-A) is an effective treatment for palmar hyperhidrosis. BTX-A acts by blocking acetylcholine release at the neuro-muscular junction, inhibiting the transmission of nerve signals that trigger sweating.2 It lasts for about 6 months, although it has been reported to last for up to 12 months.3 It has relatively few side effects, and is long lasting in comparison with other medical treatments.

BTX-A treatment is available under the Pharmaceutical Benefits Scheme (PBS) for axillary hyperhidrosis, but not for palmar hyperhidrosis.

Recently two patients with palmar hyperhidrosis underwent BTX-A treatment at the Royal Darwin Hospital. BTX-A was injected into multiple injection sites over the palm, palmar surface of the fingers and thumb, and along the ulnar border of the dominant hand in the subepidermal plane (Box). The patients completed the Dermatology Life Quality Index (DLQI) before treatment and 2 weeks afterwards. Both patients had a substantial improvement in their DLQI score. One patient wrote an unsolicited letter detailing the benefits she found after treatment.

A patient’s constant awareness of such a condition affecting them impacts on all domains of their life: functional, social, personal and emotional. Our patients described a multitude of difficulties with practical tasks as well as social interaction when living with palmar hyper-hidrosis. It is a condition that can be ameliorated with subepidermal BTX-A treatment. It is disappointing that BTX-A is not available on the PBS for palmar hyperhidrosis, when such a straightforward procedure can have immense impact on the quality of life of those affected by this condition.

Markings showing 72 sites for botulinum toxin injection into the palmar surface, fingers and ulnar border of the dominant hand