Dermatology and vascular specialists in NSW want PBS and MBS listings for botulinum toxin injections extended to include  palmar hyperhidrosis.

Despite the condition impacting quality of life just as much as axillary hyperhidrosis – for which treatment with botox is PBS and MBS listed – many with excessive sweating of the palms and feet can’t access the therapy, which researchers argue is ‘a strong treatment option [that] should be given greater priority rather than used as a treatment of last resort’.

Researchers led by Sydney dermatologist Dr Robert Rosen say patients with the affliction report significant levels of social embarrassment, difficulty carrying out activities of daily living and employment, and physical discomfort.

In mild disease treatment includes topical aluminium chloride hexahydrate – antiperspirants – followed by second line therapy with either botulinum toxin A to inhibit the release of acetylcholine or iontophoresis, which involves  an electrical current bing passed through skin soaked in tap water,  saline, or a solution containing an anticholinergic medication over multiple sessions.

Fear of pain that may be associated with botox injections as well as uncertainly around efficacy have both been cited by patients as reason for foregoing the treatment and investigators say out of pocket cost also factors into a decision.

Inadequate treatment

In a bid to establish treatment efficacy and side effect profile of botulinum toxin injection for palmer hyperthdrosis, the team carried out a retrospective review of some 30 patients who received the treatment  – the largest Australian cohort to date.

Patients received 100 units of botulinum toxin A divided equally between the palms with ice, vibration and topical local anaesthetic used for analgesia.

According to investigators 20% of pattens had co-morbidities, 11% reported a family history of palmer hyperhidrosis and 77% had hyperhidrosis at other sites – a finding that suggests the disease can have ‘a high morbidity and require more than one treatment modality’.

Meanwhile 70% of patients had previously tried other treatments, note investigators adding that 93% of patients reported being botulinum toxin naïve.

“The fact that 70% of patients had failed previous treatments affirms that several patients receive inadequate treatment for their condition and that botulinum injections are considered as a treatment of last resort. In comparison, only 16.5% of our axillary hyperhidrosis patients had failed other treatments, which indicates the increased popularity of botulinum injections.”

Post-therapy, 93% of patients reported experiencing a reduction in sweating as measured on the Hyperhidrosis Disease Severity Scale (HDSS), which provides a measure of the impact of the condition on daily activities.

A 1-point improvement in HDSS score is associated with a 50% reduction in sweat production and a 2-point improvement with an 80% reduction.

With treatment proving to be  ‘highly effective’ for palmar hyperhidrosis, as well as axillary hyperhidrosis, researchers said they were now hopeful there may be scope for review of the Medicare subsidies.

The team also reported strong evidence for effect with multiple treatments, with the mean duration of effect increasing by 9 weeks between first and last treatments (P = 0.03).

And in five patients a dose higher than the standard 100 units (120–130 units) occurred, corresponding to an increase in duration of efficacy of an average 3.3 months in three of these patients. Investigators say that finding raises the question of whether all patients should receive a higher dose.

Few side effects were reported – the main being reduced hand strength, which occurs in 20–45% of patients but is often transient reportedly resolving after a few weeks.

Interestingly, 13 patients reported plantar hyperhidrosis in addition to palmar disease with five of these patients reporting a reduction in plantar sweating post palmar injections.

The finding suggests clinicians should consider treating palmar disease first, before attempting painful and expensive treatment of plantar disease, said the researchers. 

Epidemic

Writing in a linked editorial, Associate Professor Karl Ng,  neurologist and neurophysiologist at the North Shore Hospital and the University of Sydney said the condition was becoming a problem of ‘epidemic proportions’

Addressing treatment efficacy he said the study reinforced an experience that many injectors have noticed – that duration appears to increase when more treatments are rendered and usually, a longer duration of more than four months. But without a Medicare rebate and MBS item billing number, such durations will likely put the treatment well out of reach for many patients.

He also noted that many patients rate the injections as painful without adequate analgesia, which may contribute to their reticence to have regular treatment. Describing topical anaesthetic creams, ice and vibration interferential modalities as ‘somewhat cumbersome’ he suggests the use of methoxyflurane-inhaled anaesthesia to be a ‘safe and effective way to deliver toxin in an acceptable fashion’.

“It would be desirable if there is greater public and policy-making recognition soon that palmar and plantar HH are just as much a curse as axillary HH, and that could pave the way for a much-needed future listing of toxin treatment on the PBS/MBS,” he concluded.

The study and editorial are published in Internal Medicine Journal.