Botulinum toxin in the treatment of palmar hyperhidrosis

Treatment options for hyperhidrosis

Hyperhidrosis is a disorder of excessive sweating beyond what is expected for thermoregulatory needs and environmental conditions. Primary hyperhidrosis has an estimated prevalence of nearly 3% and is associated with significant medical and psychosocial consequences. Most cases of hyperhidrosis involve areas of high eccrine density, particularly the axillae, palms, and soles, and less often the craniofacial area. Multiple therapies are available for the treatment of hyperhidrosis. Options include topical medications (most commonly aluminum chloride), iontophoresis, botulinum toxin injections, systemic medications (including glycopyrrolate and clonidine), and surgery (most commonly endoscopic thoracic sympathectomy [ETS]). The purpose of this article is to comprehensively review the literature on the subject, with a focus on new and emerging treatment options. Updated therapeutic algorithms are proposed for each commonly affected anatomic site, with practical procedural guidelines. For axillary and palmoplantar hyperhidrosis, topical treatment is recommended as first-line treatment. For axillary hyperhidrosis, botulinum toxin injections are recommended as second-line treatment, oral medications as third-line treatment, local surgery as fourth-line treatment, and ETS as fifth-line treatment. For palmar and plantar hyperhidrosis, we consider a trial of oral medications (glycopyrrolate 1-2 mg once or twice daily preferred to clonidine 0.1 mg twice daily) as second-line therapy due to the low cost, convenience, and emerging literature supporting their excellent safety and reasonable efficacy. Iontophoresis is considered third-line therapy for palmoplantar hyperhidrosis; efficacy is high although so are the initial levels of cost and inconvenience. Botulinum toxin injections are considered fourth-line treatment for palmoplantar hyperhidrosis; efficacy is high though the treatment remains expensive, must be repeated every 3-6 months, and is associated with pain and/or anesthesia-related complications. ETS is a fifth-line option for palmar hyperhidrosis but is not recommended for plantar hyperhidrosis due to anatomic risks. For craniofacial hyperhidrosis, oral medications (either glycopyrrolate or clonidine) are considered first-line therapy. Topical medications or botulinum toxin injections may be useful in some cases and ETS is an option for severe craniofacial hyperhidrosis.

Botulinum toxin for hyperhidrosis: a review

Primary focal hyperhidrosis is a disorder of idiopathic excessive sweating that typically affects the axillae, palms, soles, and face. The disorder, which affects up to 2.8% of the US population, is associated with considerable physical, psychosocial, and occupational impairments. Current therapeutic strategies include topical aluminum salts, tap-water iontophoresis, oral anticholinergic agents, local surgical approaches, and sympathectomies. These treatments, however, have been limited by a relatively high incidence of adverse effects and complications. Non-surgical treatment complications are typically transient, whereas those of surgical therapies may be permanent and significant. Recently, considerable evidence suggests that botulinum toxin type A (BTX-A) injections into hyperhidrotic areas can considerably reduce focal sweating in multiple areas without major adverse effects. BTX-A has therefore shown promise as a potential replacement for more invasive treatments after topical aluminum salts have failed. This article reviews the epidemiology, diagnosis, and management of primary focal hyperhidrosis, with an emphasis on recent research evidence supporting the use of BTX-A injections for this indication.

Treatment of hyperhidrosis with botulinum toxin

Focal idiopathic and episodic eccrine sweating of the axillae, palms, soles, and face troubles afflicted individuals with a social curse that can only be imagined by those whose hands or underarms dampen only occasionally. Although there is no accurate incidence in the epidemiology literature, it seems that about half of the patients who have presented to the author with this condition have at least one first-degree relative similarly affected. Social stigma, lack of understanding on the part of medical providers as to the cause and nature of the problem, and lack of effective therapy keeps most of these patients from seeking medical care. This article investigates the treatment of hyperhidrosis with botulinum toxin.

Hyperhidrosis and botulinum toxin A: patient selection and techniques

Focal idiopathic excessive eccrine sweating presents most commonly as an affliction of three anatomically distinct area: the axillae, the palms and soles, and the upper face. The true incidence is not known, but about half of the patients referred to us with this condition have at least one first-degree relative similarly affected. Only a fraction of patients afflicted are thought to seek medical care because of the social stigma, lack of understanding on the part of medical providers as to the cause and nature of the problem, and, until now, lack of effective nonsurgical therapy. A large social sample is required to accurately measure both the incidence and the exact nature of the genetic influence.

Botulinum toxin-B and the management of hyperhidrosis

A new serotype of botulinum toxin has recently arrived in the US. Botulinum toxin type B (BTX-B), known as Myobloc in the United States and as Neurobloc in Europe, is one of seven different antigenic members of the botulinum toxin family, five of which the human nervous system is susceptible to. Like botulinum toxin type A (BTX-A), BTX-B has been used for a myriad of both dermatologic and nondermatologic problems since its recent approval by the FDA for the treatment of cervical dystonia in December 2000. It is currently not approved however, for a cosmetic use but has been used for this purpose in an "off-label" fashion. It has followed in the therapeutic footsteps of BTX-A in the prevention and treatment of facial wrinkles such as crow's feet and glabellar frown lines. In addition, one of its current and popular uses is in the management of hyperhidrosis, a disease in search of a long needed treatment. This past year researchers have been investigating the efficacy as well as defining the dosing and application regiments of BTX-B in the treatment of hyperhidrosis. In addition, recent studies have been examining its side effect profile, which may be very different than that seen with BTX-A. There are only a handful of studies in the literature examining the cosmetic applications of BTX-B. This chapter will review what is currently known about BTX-B and its current use in regards to the treatment of hyperhidrosis.

A review of peripheral nerve blockade as local anaesthesia in the treatment of palmar hyperhidrosis

Injection of botulinum toxin type A (BTX-A) is an effective method of controlling palmar hyperhidrosis. It is, however, an uncomfortable procedure without adequate anaesthesia. We outline the techniques used, the reasons for them and potential pitfalls that can be avoided, with an outline of the neural anatomy relevant to the palmar injection of BTX-A. We have been using peripheral nerve blockade as local anaesthesia during BTX-A treatment of palmar hyperhidrosis for the last few years, and have found it an effective method of providing pain relief during the procedure, giving greater anaesthesia than that given by topical anaesthetic cream under occlusion and ice. It has been our experience that patients prefer wrist blockade to topical anaesthesia and ice when receiving BTX-A injections for treatment of palmar hyperhidrosis.

[Sialorrhea, hyperhidrosis and botulinum toxin]

OBJECTIVE

The first clinical studies indicate that Botox provides effective treatment for hyperhidrosis and sialorrhea. The aim of this work is to sum up current evaluation of this use.

METHOD

A systematic literature search was conducted on the Pub Med database, along with on chapters in other publications. The most interesting articles in relation to our own personal experience were chosen.

RESULTS

Despite recent use of BT to treat focal hyperhidrosis, there have been numerous publications since 1997. However, the injected areas have not been listed so frequently. Axillary hyperhidrosis has been studied most; it is also in this case and in the case of gustatory sweating that the best results have been obtained. Publications about palmar and especially plantar hyperhidrosis are much rarer, almost anecdotic. It has been demonstrated to a lesser extent that BT injections are effective in these cases. Literature about sialorrhea is just beginning. However, the reduction of the production of saliva following intra parenchymatic injection of toxin into the parotid and submandibular glands, thus rarifying drooling, has been demonstrated. For each of the pathological indications, both the injection techniques and the optimal doses remain to be determined.

DISCUSSION

Because BT blocks all cholinergic transmission, including the autonomous nervous system, it was plausible to expect a reduction in sweating and salivation on local injection of the product. In fact, the first publications indicated such efficiency without serious side effects. For hyperhidrosis, there has developed a consensus for making intracutaneous injections only. Of the injections in axillary areas, the palms of the hands, the plantar regions, the face or other cutaneous areas, palmoplantar hyperhidrosis is the least accessible, in any case causes the most technical problems, because of difficulty in pain management. For sialorrhea and the drooling that accompanies certain chronical neurological diseases, BT seems to have very promising effects. However, it has not been precisely determined whether to inject the parotid gland, the submandibular gland, or both. Necessary and sufficient means of targeting are still imprecise. It also remains to be determined the number of sites per gland and the doses to be injected.

Efficacy and safety of botulinum toxin type a in the treatment of palmar hyperhidrosis: a double-blind, randomized, placebo-controlled study

BACKGROUND

Recent studies demonstrate that botulinum toxin type A (BTX-A) decreases palmar hyperhidrosis.

OBJECTIVE

To evaluate the efficacy and safety of BTX-A for palmar hyperhidrosis.

METHODS

Patients (n = 19) received injections of placebo (normal saline) in one hand and BTX-A in the other. Assessments included gravimetric measurement of sweat production and physician's and patient's rating of severity. Safety evaluations included measuring grip strength. Preliminary 28-day results are reported.

RESULTS

The mean percentage decrease in gravimetric measurement at day 28 was significantly greater with BTX-A versus placebo. One hundred percent of 17 patients rated the treatment as successful, while only 12% (2/17) rated placebo injection successful. Grip and hand strength were unchanged with either treatment. Only 21% (4/19) reported mild adverse events.

CONCLUSION

BTX-A injections produce significant improvements in palmar hyperhidrosis without a concomitant decrease in grip or dexterity, or the occurrence of serious adverse events.

Side-effects of intradermal injections of botulinum A toxin in the treatment of palmar hyperhidrosis: a neurophysiological study

Focal palmar hyperhidrosis can be effectively abolished by intradermal injections with botulinum toxin. Muscle weakness of finger grip has been reported as a reversible side-effect of this new treatment. The objective of this work was to measure muscular side-effects after treatment of palmar hyperhidrosis with botulinum toxin. As botulinum toxin has been used in the treatment of pain, we studied whether the toxin might influence afferent thin-fibre function by measuring temperature perception thresholds. Thirty-seven patients treated with botulinum toxin (Botox, Allergan Pharmaceuticals, Irvine, CA, USA) showed a decrease in compound muscle action potential (CMAP) for both abductor pollicis brevis (APB) and abductor digiti minimi (ADM) compared with pre-injection values on average by 64 and 36%, respectively, at 3 weeks which returned nearly to normal at 37 weeks. Muscle power for both finger abduction and finger opposition decreased to a lesser extent. Repetitive nerve stimulation and single fibre electromyography (EMG) showed a disturbed neuromuscular transmission. Thus, despite careful technique with small doses of botulinum toxin injected intradermally, the toxin diffuses to underlying muscles. With regard to the present results, one should be careful in using higher doses of Botox than 0.8 mU/cm(2) in the palmar skin above intrinsic muscles. No influence on thin-fibre function was seen.

Treatment of focal hyperhidrosis with botulinum toxin type A: long-term follow-up in 61 patients

BACKGROUND

The blocking action of botulinum toxin type A (BTX-A) on cholinergically innervated sweat glands has been used successfully to treat patients with focal hyperhidrosis.

OBJECTIVES

To investigate the long-term efficacy and safety of intradermal injections of BTX-A.

METHODS

We performed an open-label study in 61 patients treated over a period of 3 years for axillary or palmar hyperhidrosis. A total dose of 400 mU BTX-A (Dysport) was injected into both axillae or 460 mU BTX-A (Dysport) into both palms. The injections were repeated after relapse. Objective quantification of sweat production was performed using digitized ninhydrin-stained sheets.

RESULTS

Four weeks after BTX-A treatment the median reduction in sweat production was 71% compared with baseline (P < 0.001) in the axillary group and 42% (P = 0.005) in the palmar group. Subjective assessment of sweat production by the patients using a visual analogue scale (0, no sweating; 100, the most severe sweating) showed a significant reduction in both the axillary (P < 0.001) and palmar groups (P < 0.001). Secondary disturbances due to focal hyperhidrosis interfering with daily activities were markedly improved in both groups. The median time interval between the sets of injections was 34 weeks for axillary hyperhidrosis and 25 weeks for palmar hyperhidrosis. The treatment of palmar hyperhidrosis was complicated by transient but not disabling weakness of the small hand muscles in nine of 21 patients.

CONCLUSIONS

Repeated intradermal injections of BTX-A in patients with axillary and palmar hyperhidrosis are as effective as first treatments.

Treatment of palmar hyperhidrosis with botulinum toxin

Excessive sweating of the palms, axillae, and soles can be managed with intradermal injections of botulinum toxin as an alternative to more aggressive surgical therapies such as sympathectomy and less effective techniques including topical antiperspirants. The dosage and injection techniques can be optimized to provide several months of freedom from this troubling disorder.

Pharmacology of botulinum toxin

BACKGROUND

Botulinum toxin has a well-defined role among dermatologists for the treatment of facial wrinkling, brow position, and palmar and axillary hyperhidrosis.

OBJECTIVE

The purpose of this study is to educate dermatologists on the pharmacology of botulinum toxin.

METHODS

A retrospective review of the literature on botulinum toxin from 1962 to the present was conducted. We examined the clinical applications of botulinum toxin, cholinergic neuromuscular transmission, the toxin's structure and molecular actions, drug and disease interactions at the neuromuscular junction, toxin assays, determinants of clinical response, and adverse side effects.

RESULTS

Botulinum toxin blocks the release of acetylcholine from the presynaptic terminal of the neuromuscular junction. Several drugs and diseases interfere with the neuromuscular junction and the effects of botulinum toxin. The mouse bioassay, the most sensitive and specific measurement of toxin activity, is the gold standard for botulinum toxin detection and standardization. The major determinants of clinical response to treatment are the toxin preparation, individual patient's anatomy, dose and response relationships, length of toxin storage after reconstitution, and immunogenicity. To minimize potential antibody resistance, one should use the smallest effective dose, utilize treatment intervals of more than 3 months, and avoid booster injections. Uncommon adverse effects include ptosis, ectropion, diplopia, bruising, eyelid drooping, hematoma formation, and temporary headaches.

CONCLUSION

Botulinum toxin is a safe and effective treatment. Knowledge of the pharmacologic basis of therapy will be useful for standardizing techniques and achieving consistent therapeutic results in the future.