Effect of transdermal botulinum toxin on sweat secretion in subjects with idiopathic palmar hyperhidrosis

Fractional CO2 laser-assisted Botulinum toxin type A delivery for the treatment of primary palmar hyperhidrosis

Intradermal injections of botulinum toxin type A (BTX-A) have been used successfully to treat patients with primary palmoplantar hyperhidrosis (PPH). However, problems with local injections of BTX-A for palmar hyperhidrosis include injection pain and reduced palmar muscle strength. This case series describes three patients with PPH. Patients were followed up for 3 months and assessed using the minor iodine starch test and the visual analog scale (VAS). Over two sessions within a 2-week interval, all patients received treatment on one palm, while the other palm served as the untreated control. Treated palms received fractional CO₂ laser therapy and immediate post-operative topical application of BTX-A solution for a total of 50 units. Sweat production was assessed based on the size of the sweat-producing area (measured by the minor iodine starch test) and subjective assessment of sweat production using the visual analog scale (VAS) at baseline, 2 weeks after the first treatment, and 1, 2, and 3 months after the second treatment. In the BTX-A-treated palm, the decrease in the mean sweat production was 51.6% at 2 weeks after the first treatment, and 88.5%, 67.8%, and 52.9%, at 1, 2, and 3 months after the final treatment when compared to the baseline. In the untreated palms, the decrease in the mean sweat production was 2% on all follow-ups when compared to the baseline. No adverse effect was observed in any patient. Fractional CO₂ laser is a safe technique for BTX-A delivery on the palm area and is demonstrated to be safe and effective in decreasing sweat secretion of hyperhidrosis palm.

Interventions for hyperhidrosis in secondary care: a systematic review and value-of-information analysis

BACKGROUND

Hyperhidrosis is uncontrollable excessive sweating that occurs at rest, regardless of temperature. The symptoms of hyperhidrosis can significantly affect quality of life. The management of hyperhidrosis is uncertain and variable.

OBJECTIVE

To establish the expected value of undertaking additional research to determine the most effective interventions for the management of refractory primary hyperhidrosis in secondary care.

METHODS

A systematic review and economic model, including a value-of-information (VOI) analysis. Treatments to be prescribed by dermatologists and minor surgical treatments for hyperhidrosis of the hands, feet and axillae were reviewed; as endoscopic thoracic sympathectomy (ETS) is incontestably an end-of-line treatment, it was not reviewed further. Fifteen databases (e.g. CENTRAL, PubMed and PsycINFO), conference proceedings and trial registers were searched from inception to July 2016. Systematic review methods were followed. Pairwise meta-analyses were conducted for comparisons between botulinum toxin (BTX) injections and placebo for axillary hyperhidrosis, but otherwise, owing to evidence limitations, data were synthesised narratively. A decision-analytic model assessed the cost-effectiveness and VOI of five treatments (iontophoresis, medication, BTX, curettage, ETS) in 64 different sequences for axillary hyperhidrosis only.

RESULTS AND CONCLUSIONS

Fifty studies were included in the effectiveness review: 32 randomised controlled trials (RCTs), 17 non-RCTs and one large prospective case series. Most studies were small, rated as having a high risk of bias and poorly reported. The interventions assessed in the review were iontophoresis, BTX, anticholinergic medications, curettage and newer energy-based technologies that damage the sweat gland (e.g. laser, microwave). There is moderate-quality evidence of a large statistically significant effect of BTX on axillary hyperhidrosis symptoms, compared with placebo. There was weak but consistent evidence for iontophoresis for palmar hyperhidrosis. Evidence for other interventions was of low or very low quality. For axillary hyperhidrosis cost-effectiveness results indicated that iontophoresis, BTX, medication, curettage and ETS was the most cost-effective sequence (probability 0.8), with an incremental cost-effectiveness ratio of £9304 per quality-adjusted life-year. Uncertainty associated with study bias was not reflected in the economic results. Patients and clinicians attending an end-of-project workshop were satisfied with the sequence of treatments for axillary hyperhidrosis identified as being cost-effective. All patient advisors considered that the Hyperhidrosis Quality of Life Index was superior to other tools commonly used in hyperhidrosis research for assessing quality of life.

LIMITATIONS

The evidence for the clinical effectiveness and safety of second-line treatments for primary hyperhidrosis is limited. This meant that there was insufficient evidence to draw conclusions for most interventions assessed and the cost-effectiveness analysis was restricted to hyperhidrosis of the axilla.

FUTURE WORK

Based on anecdotal evidence and inference from evidence for the axillae, participants agreed that a trial of BTX (with anaesthesia) compared with iontophoresis for palmar hyperhidrosis would be most useful. The VOI analysis indicates that further research into the effectiveness of existing medications might be worthwhile, but it is unclear that such trials are of clinical importance. Research that established a robust estimate of the annual incidence of axillary hyperhidrosis in the UK population would reduce the uncertainty in future VOI analyses.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42015027803.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

The etiology, diagnosis, and management of hyperhidrosis: A comprehensive review: Therapeutic options

Hyperhidrosis (HH) is a chronic disorder of excess sweat production that may have a significant adverse effect on quality of life. A variety of treatment modalities currently exist to manage HH. Initial treatment includes lifestyle and behavioral recommendations. Antiperspirants are regarded as the first-line therapy for primary focal HH and can provide significant benefit. Iontophoresis is the primary remedy for palmar and plantar HH. Botulinum toxin injections are administered at the dermal-subcutaneous junction and serve as a safe and effective treatment option for focal HH. Oral systemic agents are reserved for treatment-resistant cases or for generalized HH. Energy-delivering devices such as lasers, ultrasound technology, microwave thermolysis, and fractional microneedle radiofrequency may also be utilized to reduce focal sweating. Surgery may be considered when more conservative treatments have failed. Local surgical techniques, particularly for axillary HH, include excision, curettage, liposuction, or a combination of these techniques. Sympathectomy is the treatment of last resort when conservative treatments are unsuccessful or intolerable, and after accepting secondary compensatory HH as a potential complication. A review of treatment modalities for HH and a sequenced approach are presented.

The Expanding Therapeutic Utility of Botulinum Neurotoxins

Botulinum neurotoxin (BoNT) is a major therapeutic agent that is licensed in neurological indications, such as dystonia and spasticity. The BoNT family, which is produced in nature by clostridial bacteria, comprises several pharmacologically distinct proteins with distinct properties. In this review, we present an overview of the current therapeutic landscape and explore the diversity of BoNT proteins as future therapeutics. In recent years, novel indications have emerged in the fields of pain, migraine, overactive bladder, osteoarthritis, and wound healing. The study of biological effects distal to the injection site could provide future opportunities for disease-tailored BoNT therapies. However, there are some challenges in the pharmaceutical development of BoNTs, such as liquid and slow-release BoNT formulations; and, transdermal, transurothelial, and transepithelial delivery. Innovative approaches in the areas of formulation and delivery, together with highly sensitive analytical tools, will be key for the success of next generation BoNT clinical products.

Peptide-mediated transdermal delivery of botulinum neurotoxin type A reduces neurogenic inflammation in the skin

Release of inflammatory pain mediators from peripheral sensory afferent endings contributes to the development of a positive feedback cycle resulting in chronic inflammation and pain. Botulinum neurotoxin type A (BoNT-A) blocks exocytosis of neurotransmitters and may therefore block the release of pain modulators in the periphery. Subcutaneous administration of BoNT-A (2.5, 5 and 10U) reduced plasma extravasation (PE) caused by electrical stimulation of the saphenous nerve or capsaicin in the rat hindpaw skin (ANOVA, Post hoc Tukey, p<0.05, n=6). Subcutaneous BoNT-A also reduced blood flow changes evoked by saphenous nerve stimulation (ANOVA, Post hoc Tukey, p<0.05, n=6). Subcutaneous BoNT-A had no effect on PE induced by local injection of substance P (SP) or vasodilation induced by local CGRP injection. Although BoNT-A is an effective treatment for a wide range of painful conditions, the toxin's large size necessitates that it be injected at numerous sites. We found that a short synthetic peptide (TD-1) can facilitate effective transdermal delivery of BoNT-A through intact skin. Coadministration of TD-1 and BoNT-A to the hindpaw skin resulted in a significant reduction in PE evoked by electrical stimulation. The findings show that BoNT-A can be administered subcutaneously or topically with a novel transdermal delivery peptide to reduce inflammation produced by activating nociceptors in the skin. Peptide-mediated delivery of BoNT-A is an easy and non-invasive way of administering the toxin that may prove to be useful in clinical practice.