Sweat gland morphology and periglandular innervation in essential palmar hyperhidrosis before and after treatment with intradermal botulinum toxin

Anatomical proposal of local anesthesia injection for median nerve block in treating hyperhidrosis with botulinum neurotoxin

INTRODUCTION

Hyperhidrosis, causing excessive sweat, can be treated with Botulinum neurotoxin injection. Botulinum toxin, an effective and safe treatment for hyperhidrosis, unfortunately involves significant pain due to multiple injections. This study aims to propose a more efficient and less painful approach to nerve blocks for relief, by identifying optimal injection points to block the median nerve, thereby enhancing palmar hyperhidrosis treatment.

METHODS

This study, involving 52 Korean cadaver arms (mean age 73.5 years), measured the location of the median nerve relative to the transverse line at the pisiform level to establish better nerve block injection sites.

RESULTS

In between the extensor carpi radialis and palmaris longus, the median nerve was located at an average distance of 47.39 ± 6.43 mm and 29.39 ± 6.43 mm from the transverse line at the pisiform level.

DISCUSSION

To minimize discomfort preceding the botulinum neurotoxin injection, we recommend the optimal injection site for local anesthesia to be located 4 cm distal to the transverse line of the pisiform, within the tendons of the palmaris longus and flexor carpi radialis muscles.

The Isolated Mouse Jejunal Afferent Nerve Assay as a Tool to Assess the Effect of Botulinum Neurotoxins in Visceral Nociception

For the past two decades, botulinum neurotoxin A (BoNT/A) has been described as a strong candidate in the treatment of pain. With the production of modified toxins and the potential new applications at the visceral level, there is a real need for tools allowing the assessment of these compounds. In this study, we evaluated the jejunal mesenteric afferent nerve assay to investigate BoNT/A effects on visceral nociception. This ex vivo model allowed the continuous recording of neuronal activity in response to various stimuli. BoNT/A was applied intraluminally during three successive distensions, and the jejunum was distended every 15 min for 3 h. Finally, samples were exposed to external capsaicin. BoNT/A intoxication was validated at the molecular level with the presence of cleaved synaptosomal-associated protein of 25 (SNAP25) in nerve terminals in the mucosa and musculosa layers 3 h after treatment. BoNT/A had a progressive inhibitory effect on multiunit discharge frequency induced by jejunal distension, with a significant decrease from 1 h after application without change in jejunal compliance. The capsaicin-induced discharge was also affected by the toxin. This assay allowed the description of an inhibitory effect of BoNT/A on afferent nerve activity in response to distension and capsaicin, suggesting BoNT/A could alleviate visceral nociception.

Techniques to Relieve Pain Associated With Botulinum Injections for Palmar and Plantar Hyperhidrosis

BACKGROUND

Palmar and plantar hyperhidrosis (HH) is a common condition characterized by excessive sweating of the palms and soles. Botulinum neurotoxin (BTX) is a very effective and safe treatment. However, the associated intense injection pain is a major limiting factor deterring patients from selecting this treatment.

OBJECTIVE

The aim of this study was to review the numerous techniques used to minimize pain accompanying injections for palmoplantar HH. Additionally, the advantages and limitations of each modality will be discussed.

MATERIALS AND METHODS

The authors performed a comprehensive literature search in PubMed/MEDLINE, Embase, Cochrane Central, and Google Scholar on randomized controlled trials, cohort studies, and case series on techniques to relieve pain of BTX injections for treatment of palmar and plantar HH.

RESULTS

Current available techniques in reducing botulinum injection with merits and drawbacks are nerve blocks, Bier blocks, cryoanalgesia, needle-free anesthesia, topical anesthetics, and vibration anesthesia.

CONCLUSION

Topical anesthesia, ice, and vibration are the safest and most convenient noninvasive available methods to relieve pain associated with botulinum injection. Nerve blocks, Bier block, and needle-free anesthesia provide better anesthesia but are limited by the need for training and equipment.

Heart Rate Variability Assessment and Its Application for Autonomic Function Evaluation in Patients with Hyperhidrosis

BACKGROUND

Pathophysiology mechanism of primary focal hyperhidrosis (PFHH) is controversial. Heart rate variability (HRV) could explain if there is a systemic component present. We aimed to investigate the functions of the autonomic nervous system in patients diagnosed with PFHH compared to controls using the analysis of HRV in the domains of time, frequency, and nonlinearity, as well as analysis of the recurrence plots (RPs).

METHODS

We selected 34 patients with PFHH (29.4 ± 10.2 years) and 34 controls (29.2 ± 9.6 years) for HRV analysis. Heart beats were recorded with Polar RS800CX monitor (20 min, at rest, in supine position), and RR intervals were analyzed with Kubios Premium HRV software. RPs were constructed with Visual Recurrence Analysis software. Statistical analysis included unpaired t test (p < 0.05).

RESULTS

Our results showed that HRV parameters in the 3 domains evaluated did not show any differences between the groups. The same was observed with RPs.

CONCLUSIONS

The findings suggest that PFHH, from the pathophysiological point of view, may be caused by peripheral involvement of the sympathetic nervous system (glandular level or nerve terminals), as there was no difference between the groups studied. More specific studies should help elucidate this issue.

Neuronal selectivity of botulinum neurotoxins

Botulinum neurotoxins (BoNTs) are highly potent toxins responsible for a severe disease, called botulism. They are also efficient therapeutic tools with an increasing number of indications ranging from neuromuscular dysfunction to hypersecretion syndrome, pain release, depression as well as cosmetic application. BoNTs are known to mainly target the motor-neurons terminals and to induce flaccid paralysis. BoNTs recognize a specific double receptor on neuronal cells consisting of gangliosides and synaptic vesicle protein, SV2 or synaptotagmin. Using cultured neuronal cells, BoNTs have been established blocking the release of a wide variety of neurotransmitters. However, BoNTs are more potent in motor-neurons than in the other neuronal cell types. In in vivo models, BoNT/A impairs the cholinergic neuronal transmission at the motor-neurons but also at neurons controlling secretions and smooth muscle neurons, and blocks several neuronal pathways including excitatory, inhibitory, and sensitive neurons. However, only a few reports investigated the neuronal selectivity of BoNTs in vivo. In the intestinal wall, BoNT/A and BoNT/B target mainly the cholinergic neurons and to a lower extent the other non-cholinergic neurons including serotonergic, glutamatergic, GABAergic, and VIP-neurons. The in vivo effects induced by BoNTs on the non-cholinergic neurons remain to be precisely investigated. We report here a literature review of the neuronal selectivity of BoNTs.

Distribution characteristics of sweat gland nerve fibres in normal humans identified by acetylcholinesterase histochemical staining

OBJECTIVE

To quantitatively analyze distribution characteristics of sweat gland nerve fibres (SGNF) in normal Chinese individuals for obtaining a reference for early diagnosis of peripheral neuropathy.

PATIENTS AND METHODS

Skin biopsy samples were collected from 192 normal Chinese individuals and divided into six, four and two groups according to anatomic sites, age and gender, respectively. SGNF morphology was observed and SGNF density (SGNFD) was determined.

RESULTS

There was a significant difference in SGNFD among different anatomic sites, age and gender. A degressive tendency was observed from proximal to distal anatomic sites. SGNFD was the lowest in subjects in the 21-40-year-old age group, but was the highest in subjects in the >61-year-old age group. Overall, SGNFD fluctuated with age. SGNFD in males was significantly higher than that in females.

CONCLUSIONS

Distribution characteristics of SGNF in normal individuals may serve as a reference for early diagnosis of nerve fibre damage.

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.

Botulinum neurotoxin A injection for the treatment of epiphora with patent lacrymal ducts

HEADINGS

Retrospective longitudinal study to evaluate the efficacy of botulinum neurotoxin A (BoNT/A) therapy for epiphora with patent lacrimal ducts.

BACKGROUND/PURPOSE

BoNT/A has been used since 2000 in axillary hyperhidrosis to reduce sweat secretion. Some isolated cases of hyperlacrimation or crocodile tear syndrome have been treated with BoNT/A on this basis. We report our experience in the treatment of tearing despite patent lacrimal ducts by BoNT/A injection into the lacrimal gland.

METHODS

We reviewed qualitative and quantitative criteria to evaluate the degree of improvement of epiphora after BoNT/A injections in the palpebral lobe of the lacrimal gland in patients referred for epiphora despite patent lacrimal ducts between 2009 and 2016. Epiphora was graded using a functional questionnaire, Munk score and Schirmer test performed before and after the injections. Side effects were recorded.

RESULTS

Sixty-five palpebral lacrimal glands of forty-two patients with epiphora despite patent lacrimal ducts, of mean age 65 years, sex ratio 0.8, were treated with BoNT/A (IncobotulinumtoxinA, XEOMIN^®, MERZ Pharma France) from April 2009 to April 2016. The etiology of the epiphora was represented by 56 paroxysmal lacrimal hypersecretion, 2 crocodile tear syndrome and 7 facial palsies. No conventional medical or surgical treatment had been effective in these cases. The technique of injection, dilution and dosage of BoNT/A were specific. We re-injected 33/65 cases a second time upon patient request due to recurrence of epiphora, 16/65 cases three times, 8/65 cases four times, 6/65 cases five times and 3/65 six times. The Schirmer's test measured a decrease of lacrimal secretion in 51/65 glands (78%) after the first botulinum neurotoxin injection. Side effects were limited to ptosis in 2 cases (3%) and six patients (9%) with rapidly regressing diplopia. Two patients experienced immediate lacrimal gland hematoma (3%) with no sequelae. The authors describe the injection techniques, the dosage, the volume and concentration of BoNT/A.

CONCLUSION

Patients with intractable epiphora despite patent lacrimal ducts can be effectively treated with BoNT/A (IncobotulinumtoxinA) injection into the palpebral lobe of the lacrimal gland. Most of the patients (80%) were very satisfied with few side effects (hematoma, ptosis or mild diplopia lasting from 3 days to 3 weeks). More studies are needed to delineate which types of epiphora can be treated with BoNT A.

Treatment of Chronic Migraine with OnabotulinumtoxinA: Mode of Action, Efficacy and Safety

Background: Chronic migraine is a common, highly disabling, underdiagnosed and undertreated entity of migraine. It affects 0.9%–2.2% of the general adult population. The present paper overviews the preclinical and clinical data regarding the therapeutic effect of onabotulinumtoxinA in chronic migraineurs. Methods: A literature search was conducted in the database of PubMed up to 20 May 2015 for articles related to the pathomechanism of chronic migraine, the mode of action, and the efficacy, safety and tolerability of onabotulinumtoxinA for the preventive treatment of chronic migraine. Results: The pathomechanism of chronic migraine has not been fully elucidated. The mode of action of onabotulinumtoxinA in the treatment of chronic migraine is suggested to be related to the inhibition of the release of calcitonin gene-related peptide and substance P in the trigeminovascular system. Randomized clinical trials demonstrated that long-term onabotulinumtoxinA fixed-site and fixed-dose (155–195 U) intramuscular injection therapy was effective and well tolerated for the prophylactic treatment of chronic migraine. Conclusions: Chronic migraine is a highly devastating entity of migraine. Its exact pathomechanism is unrevealed. Two-third of chronic migraineurs do not receive proper preventive medication. Recent clinical studies revealed that onabotulinumtoxinA was an efficacious and safe treatment for chronic migraine.

Repetitive injections of botulinum toxin A continuously increase the duration of efficacy in primary axillary hyperhidrosis: a retrospective analysis in 101 patients

BACKGROUND AND OBJECTIVES

Botulinum toxin type A is an effective, well-tolerated, albeit temporary treatment for primary axillary hyperhidrosis. However, little is known about the influence of repetitive injections on the duration of efficacy.

PATIENTS AND METHODS

139 patients with primary axillary hyperhidrosis were injected with 50 units of botulinum toxin per axilla. In 101 patients, who received at least three treatments, the duration of efficacy after the first, second, and last treatment was evaluated.

RESULTS

The median duration of efficacy was 4.0 months, 4.5 months, and 5.0 months after the first, second, and last injection, respectively. Overall, the duration of efficacy was significantly longer after the last injection compared to the duration of efficacy after the first injection (p = 0.0055, Wilcoxon matched-pairs signed-rank test). Likewise, the difference between the first and second injection (p = 0.0302) as well as the difference between the second and the last injection (p = 0.0381) were significant. In 25.7 % of patients, the duration of efficacy remained unchanged over the entire treatment period.

CONCLUSIONS

Repetitive botulinum toxin treatments led to a significantly increased duration of efficacy in axillary hyperhidrosis. While the average duration of efficacy continued to increase with each treatment, there were considerable interindividual differences.

Evaluation of trace elements, calcium, and magnesium levels in the plasma and erythrocytes of patients with essential hyperhidrosis

BACKGROUND

Essential hyperhidrosis is a disease that expresses itself with excessive sweating in palmar, plantar, axillary, and craniofacial regions. The etiopathogenesis of the disease, which has particular importance because of leading to psychosocial morbidity, could have not been completely elucidated. In previous studies, it has been shown that oxidative stress might play a role in the pathogenesis.

AIMS

Assessing the levels of trace elements such as Se, Zn, Cu, Fe, and Mg that have an important role in oxidative stress, as well as Ca and Mg that have an important role in membrane physiology, in patients with essential hyperhidrosis.

MATERIALS AND METHODS

Blood samples taken from the patient group with essential hyperhidrosis (42) and the control group (37) were separated into plasma and erythrocytes, and the levels of the bioelements were measured by use of ICP-OES device.

RESULTS

Erythrocyte levels of Se, Fe, Cu, Zn, Ca, and Mg were detected significantly higher in patients with essential hyperhidrosis. Furthermore, plasma levels of Cu, Ca, and Mg were significantly lower in patients with essential hyperhidrosis. Plasma levels of Se, Fe, and Zn showed no statistical difference between two groups.

DISCUSSION

It was thought that the high levels of Cu and Fe in erythrocytes may play a role in increased intracellular oxidative stress, whereas the increase in Se and Zn levels may be secondary to increased oxidative stress. Low extracellular concentrations of Ca and Mg raise the thought that they play a role either enhancing the membrane excitability of eccrine sweat glands or influencing the autonomic nerve system.

CONCLUSION

The levels of trace elements, which were determined to be different from the control group, may play a role in the pathogenesis of essential hyperhidrosis either in direct relation with or without oxidative mechanisms.

The secretory clear cell of the eccrine sweat gland as the probable source of excess sweat production in hyperhidrosis

Primary hyperhidrosis is characterized by excessive sweating in palmar, plantar and axillary body regions. Gland hypertrophy and the existence of a third type of sweat gland, the apoeccrine gland, with high fluid transporting capabilities have been suggested as possible causes. This study investigated whether sweat glands were hypertrophied in axillary hyperhidrotic patients and if mechanisms associated with fluid transport were found in all types of axillary sweat glands. The occurrence of apoeccrine sweat glands was also investigated. Axillary skin biopsies from control and hyperhidrosis patients were examined using immunohistochemistry, image analysis and immunofluorescence microscopy. Results showed that glands were not hypertrophied and that only the clear cells in the eccrine glands expressed proteins associated with fluid transport. There was no evidence of the presence of apoeccrine glands in the tissues investigated. Preliminary findings suggest the eccrine gland secretory clear cell as the main source of fluid transport in 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 in the treatment of sweat-worsened foot problems in patients with epidermolysis bullosa simplex and pachyonychia congenita

BACKGROUND

Painful foot blistering is a common problem in patients with epidermolysis bullosa simplex (EBS) and pachyonychia congenita (PC). Hyperhidrosis, a condition which can be effectively blocked by plantar injections of botulinum toxin (Btx), often exacerbates the blistering.

OBJECTIVES

A retrospective evaluation of the effects of Btx injections in 14 patients with EBS and PC with foot blisters and painful callosities.

METHODS

After informed consent, patients with EBS (n = 6) and PC (n = 8), aged 7-66 years, who had received Btx therapy at our centre since 2003, were included. The treatment consisted of multiple plantar injections of Btx A or Btx B after prior regional or general anaesthesia. Patients were interviewed about the treatment effect and were asked to score the improvement from 0 to 5, where 5 is 'excellent'. One patient with PC with painful callosities was studied by magnetic resonance (MR) spectroscopic microimaging before and after Btx injections to disclose any underlying blisters.

RESULTS

In total, 76 treatments were evaluated (one to 19 sessions per patient). Thirteen patients (93%) reported reduced plantar blistering and pain; the improvement score was ≥ 4 in four of six patients with EBS and six of eight patients with PC. The mean effect duration was 3 months. No adverse events, apart from mild anticholinergic side-effects in two patients, were noted. MR spectroscopic microimaging showed disappearance of intraepidermal blistering after Btx therapy.

CONCLUSIONS

Plantar injection of Btx is an efficient, long-lasting and safe treatment of painful blistering and callosities in EBS and PC that can be given repeatedly without loss of efficacy.

Bacterial toxins and the nervous system: neurotoxins and multipotential toxins interacting with neuronal cells

Toxins are potent molecules used by various bacteria to interact with a host organism. Some of them specifically act on neuronal cells (clostridial neurotoxins) leading to characteristics neurological affections. But many other toxins are multifunctional and recognize a wider range of cell types including neuronal cells. Various enterotoxins interact with the enteric nervous system, for example by stimulating afferent neurons or inducing neurotransmitter release from enterochromaffin cells which result either in vomiting, in amplification of the diarrhea, or in intestinal inflammation process. Other toxins can pass the blood brain barrier and directly act on specific neurons.

CGRP receptor antagonism and migraine

Calcitonin gene-related peptide (CGRP) is expressed throughout the central and peripheral nervous systems, consistent with control of vasodilatation, nociception, motor function, secretion, and olfaction. alphaCGRP is prominently localized in primary spinal afferent C and ADelta fibers of sensory ganglia, and betaCGRP is the main isoform in the enteric nervous system. In the CNS there is a wide distribution of CGRP-containing neurons, with the highest levels occurring in striatum, amygdala, colliculi, and cerebellum. The peripheral projections are involved in neurogenic vasodilatation and inflammation, and central release induces hyperalgesia. CGRP is released from trigeminal nerves in migraine. Trigeminal nerve activation results in antidromic release of CGRP to cause non-endothelium-mediated vasodilatation. At the central synapses in the trigeminal nucleus caudalis, CGRP acts postjunctionally on second-order neurons to transmit pain signals centrally via the brainstem and midbrain to the thalamus and higher cortical pain regions. Recently developed CGRP receptor antagonists are effective at aborting acute migraine attacks. They may act both centrally and peripherally to attenuate signaling within the trigeminovascular pathway.

Is active sweating during heat acclimation required for improvements in peripheral sweat gland function?

We investigated whether the eccrine sweat glands must actively produce sweat during heat acclimation if they are to adapt and increase their capacity to sweat. Eight volunteers received intradermal injections of BOTOX, to prevent neural stimulation and sweat production of the sweat glands during heat acclimation, and saline injections as a control in the contralateral forearm. Subjects performed 90 min of moderate-intensity exercise in the heat (35 degrees C, 40% relative humidity) on 10 consecutive days. Heat acclimation decreased end-exercise heart rate (156 +/- 22 vs. 138 +/- 17 beats/min; P = 0.0001) and rectal temperature (38.2 +/- 0.3 vs. 37.9 +/- 0.3 degrees C; P = 0.0003) and increased whole body sweat rate (0.70 +/- 0.29 vs. 1.06 +/- 0.50 l/h; P = 0.030). During heat acclimation, there was no measurable sweating in the BOTOX-treated forearm, but the control forearm sweat rate during exercise increased 40% over the 10 days (P = 0.040). Peripheral sweat gland function was assessed using pilocarpine iontophoresis before and after heat acclimation. Before heat acclimation, the pilocarpine-induced sweat rate of the control and BOTOX-injected forearms did not differ (0.65 +/- 0.20 vs. 0.66 +/- 0.22 mg x cm(-2) x min(-1)). However, following heat acclimation, the pilocarpine-induced sweat rate in the control arm increased 18% to 0.77 +/- 0.21 mg x cm(-2) x min(-1) (P = 0.021) but decreased 52% to 0.32 +/- 0.18 mg x cm(-2) x min(-1) (P < 0.001) in the BOTOX-treated arm. Using complete chemodenervation of the sweat glands, coupled with direct cholinergic stimulation via pilocarpine iontophoresis, we demonstrated that sweat glands must be active during heat acclimation if they are to adapt and increase their capacity to sweat.

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.

Is nitric oxide involved in the pathophysiology of essential hyperhidrosis?

BACKGROUND

Essential hyperhidrosis (EH) is a disorder of excessive, bilateral, and relatively symmetric sweating occurring in the axillae, palms, soles, or craniofacial region without obvious etiology. The expression of endothelial nitric oxide synthase (eNOS) in eccrine clear cells, reported by an immunohistochemical technique, has suggested that nitric oxide (NO) may play a role in the physiology of production and/or excretion of sweat in the human skin eccrine gland.

AIM

To determine plasma NO levels in patients with EH and healthy controls.

METHODS

We assessed the levels of plasma NO in patients with EH (n = 31) in comparison with those in age- and sex-matched healthy controls (n = 28). Total nitrite (nitrite + nitrate) was measured by a spectrophotometer at 545 nm after the conversion of nitrate to nitrite by copperized cadmium granules.

RESULTS

Plasma NO levels were found to be significantly increased in EH patients in comparison with the control group (P = 0.0001).

CONCLUSIONS

These findings indicate a possible role of increased plasma NO levels in the pathophysiology of EH.

Botulinum toxin: Clinical use

Since its development for the use of blepharospasm and strabismus more than 2.5 decades ago, botulinum neurotoxin (BoNT) has become a versatile drug in various fields of medicine. It is the standard of care in different disorders such as cervical dystonia, hemifacial spasm, focal spasticity, hyperhidrosis, ophthalmological and otolaryngeal disorders. It has also found widespread use in cosmetic applications. Many other indications are currently under investigation, including gastroenterologic and urologic indications, analgesic management and migraine. This paper is an extensive review of the spectrum of BoNT clinical applications.

Erythrocyte Oxidant/Antioxidant Status in Essential Hyperhidrosis

Essential hyperhidrosis is a disorder of excessive, bilateral, and relatively symmetric sweating occurring in the axillae, palms, soles, or craniofacial region without obvious etiology. Nitric oxide may play a physiological part in the production and/or excretion of sweat in skin eccrine glands. Tempol, a SOD mimetic, increases the half-life of NO and results in vasodilatation, hypotension, and reflex activation of sympathetic nervous system. Reactive oxygen species (ROS) may directly activate both central and peripheral sympathetic nervous system activity. We assessed the levels of malondialdehyde (MDA), the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) of red blood cells in patients with essential hyperhidrosis (n = 31) compared to age-and sex-matched healthy controls (n = 28). Erythrocyte activities of SOD and level of MDA were detected significantly higher (p = 0.020, p = 0.004 and respectively) and activities of CAT and GSH-Px were significantly lower (p = 0.0001, p = 0.0001 respectively) in patients than controls. Our results support the hypothesis that oxidative damage resulting from increased ROS production along with insufficient capacity of antioxidant mechanisms may be involved in pathogenesis of EH.

Treatment of pachyonychia congenita with plantar injections of botulinum toxin

Pachyonychia congenita (PC) is a rare genodermatosis which may be associated with painful, focal hyperkeratosis on the soles. Plantar sweating at high ambient temperatures increases the blistering of the callosities. We report three patients with PC who had great problems in walking, especially during summer time. They were treated with intracutaneous plantar injections of botulinum toxin type A (Dysport, 100 U mL(-1); Ipsen, Slough, U.K.) after prior intravenous regional anaesthesia of the foot with a low tourniquet and 25 mL prilocaine (5 mg mL(-1)). Within a week all three patients experienced dryness and a remarkable relief of pain from plantar pressure sites. The effect duration was 6 weeks to 6 months. Repeated injections over a 2-year period confirmed the good results, with no side-effects or tachyphylaxis noted.

Expanding use of botulinum toxin

Botulinum toxin type A (BTX-A) is best known to neurologists as a treatment for neuromuscular conditions such as dystonias and spasticity and has recently been publicized for the management of facial wrinkles. The property that makes botulinum toxin type A useful for these various conditions is the inhibition of acetylcholine release at the neuromuscular junction. Although botulinum toxin types A and B (BTX-A and BTX-B) continue to find new uses in neuromuscular conditions involving the somatic nervous system, it has also been recognized that the effects of these medications are not confined to cholinergic neurons at the neuromuscular junction. Acceptors for BTX-A and BTX-B are also found on autonomic nerve terminals, where they inhibit acetylcholine release at glands and smooth muscle. This observation led to trials of botulinum neurotoxins in various conditions involving autonomic innervation. The article reviews the emerging use of botulinum neurotoxins in these and selected other conditions, including sialorrhea, primary focal hyperhidrosis, pathological pain and primary headache disorders that may be of interest to neurologists and related specialists.

Hyperhidrosis: evolving therapies for a well-established phenomenon

The socially embarrassing disorder of excessive sweating, or hyperhidrosis, and its treatment options are gaining widespread attention. In order of frequency, palmar-plantar, palmar-axillary, Isolated axillary, and cranlofacial hyperhidrosis are distinct disorders of sudomotor regulation. A common link among these disorders is an excessive, nonthermoregulatory sweat response often to emotional stimuli in body regions influenced by the anterior cingulate cortex as opposed to the thermoregulatory sweat response regulated by the preoptic-anterior hypothalamus. Diagnosis of these mechanistically ambiguous disorders is primarily from patient history and physical examination, whereas results of laboratory studies performed with indicator powder reveal the distribution and severity of resting hyperhidrosis and document the integrity of thermoregulatory sweating. Treatment options lie on a continuum based on the severity of hyperhidrosis and the risks and benefits of therapy. In general, therapy begins with antiperspirants or anticholinergics. Iontophoresis is available for palmar-plantar and axillary hyperhidrosis. Botulinum toxin type A or local excision/curettage is effective for isolated axillary hyperhidrosis not responsive to topical application of aluminum chloride. Endoscopic thoracic sympathectomy may be used for severe cases of palmar-plantar and palmar-axillary hyperhidrosis. No sole therapy of choice has emerged for craniofacial sweating. The long-term sequelae of hyperhidrosis and its treatment also are discussed.