Botox (OnabotulinumtoxinA) for Treatment of Migraine Symptoms: A Systematic Review

Non-cosmetic use of botulinum toxin in surgical conditions

Botulinum toxin (BTX) is a neurotoxin that has an ability to create a fully reversible relaxation of muscles through decreased release of acethylcholin. It also has an effect on the cholinergic autoimmune nervous system, and it can reduce pain sensitization. BTX is widely used in cosmetic treatments. In recent years, BTX has increasingly been used to treat several medical and surgical conditions. In many cases, this is despite weak evidence and without approval from the European Medicine Agency (EMA). This narrative review describes how BTX is used in the different surgical specialties and provides a brief overview of the use of BTX for non-cosmetic surgical conditions.

Quality and reliability analysis of migraine Botox treatment information on YouTube

YouTube (YT) is one of the world's most well recognized video-sharing platforms that appeals to large audiences and is used by individuals to educate themselves on disease diagnosis and treatment alternatives and to distribute health-related information. Videos were searched by typing the terms "migraine botox" and "botox treatment for migraine" on the YT search bar in English. A total of 50 videos were evaluated for each term. Two independent researchers viewed the videos and documented pertinent descriptive attributes of each video, such as the upload date, number of comments, number of dislikes, number of likes, and views. The videos were analyzed and the DISCERN Global Quality Scale (GQS), Journal of the American Medical Association (JAMA) quality, and reliability scores were recorded. A total of 100 videos were assessed. The mean DISCERN score was 3.09, the mean JAMA score was 2.11, and the mean GQS score was 3.25. According to the source, 32% of the videos were uploaded by university/nonprofit physicians or professional organizations. In addition, when the DISCERN, GQS, and JAMA scores of the videos uploaded by health professionals were examined, a statistically significant difference was observed (P = .002, P = .015, and P = .002, respectively). However, no statistically significant relationship was found for the Video Popularity Index score. The reliability and quality scores of the evaluated videos uploaded by healthcare professionals for migraine Botox treatment were high, but the frequency of viewership was low. In our analysis of migraine Botox treatment videos on YT, we observed that the information on migraine Botox treatment had a wide spectrum, high-quality content, and that there were videos that may mislead viewers. In conclusion, we believe that the platform is not sufficient in its entirety, and that it should be supported with renewed, fact-checked, easy-to-understand language, and video-duration optimized videos.

A qualitative exploration of migraine in students attending Irish Universities

INTRODUCTION

The complex neurological disorder of migraine is prevalent (19%) and burdensome in university students. Qualitative research exploring the lived experience of migraine in students has yet to be conducted.

METHODS

Students clinically diagnosed with migraine were recruited (purposive sampling) from a sample of Irish third-level institutions for a one-time anonymized Zoom focus group or individual interview. Focus group questions were sent to participants in advance. Interviews were iterative. Participants were also invited to submit a drawing. The interviews were audio-recorded, transcribed, and sent to participants for triangulation. Reflexive thematic content analysis was undertaken, data was imported to Microsoft Excel, initial codes were generated, and themes and sub-themes were derived from the codes. The Standards for Reporting Qualitative Studies Checklist (S1 File) ensured study rigour.

RESULTS

Twenty students from three Irish universities participated (mean age 23.8 years). The four key themes identified were (i) Migraine Characteristics, (ii) Migraine Self-Management, (iii) Migraine Clinical Management, and (iii) Migraine Impacts. Migraine was described as not just a headache but a debilitating sensory experience. A notable high level of self-management satisfaction indicated hopeful coping strategies. However, many participants said medications were ineffective and had side effects, and clinical management could be improved. Additionally, there was a marked academic and social impact of migraine, psychological issues abounded, and several participants worried about finances.

CONCLUSIONS

Migraine is impactful in a cohort of students attending Irish third-level institutions, with students carrying a wide range of debilitating migraine burdens. Students demonstrate an attitude of resilience and determination despite these challenges. Migraine awareness and education campaigns on university campuses are warranted.

The safety and efficacy of onabotulinumtoxinA injections for children and adolescents with chronic migraine: A systematic review and meta-analysis

OBJECTIVE

To qualitatively and quantitatively summarize the evidence for the use of onabotulinumtoxinA injections in children and adolescents with migraine.

BACKGROUND

There are limited evidence-based treatment options for youth with migraine, especially youth with chronic migraine (CM). OnabotulinumtoxinA injections are an established evidence-based treatment for adults with CM. While several studies have assessed their safety and efficacy among adolescents with CM, there are no published systematic reviews summarizing the pediatric evidence.

METHODS

We carried out a systematic review, reported according to the Preferred Reporting Items for Systematic Review and Meta-Analysis, aiming to identify studies that included five or more children and adolescents aged ≤18 years with a diagnosis of migraine, who were treated with ≥50 units (U) of onabotulinumtoxinA and had outcomes assessed ≥4 weeks after one or more injection cycle. Both observational studies and randomized controlled trials (RCTs) were eligible for inclusion. Two investigators independently carried out the first (titles and abstracts) and second (full text) screening stages, as well as data extraction and quality appraisal. The American Academy of Neurology risk of bias grading scheme was used to assess study risk of bias. Studies with adequate data were pooled using random effects meta-analyses, and Hedge's g standardized mean differences with 95% confidence intervals (CIs) were generated to estimate the effect sizes of the continuous outcomes included. Studies lacking data required for meta-analysis were summarized qualitatively.

RESULTS

We screened 634 studies and included 14 studies comprising 491 participants, of whom 489 had CM. Two studies were RCTs, 12 were observational uncontrolled studies, and all but one study included only youth with CM. Five Class IV observational uncontrolled studies were amenable to pooling in meta-analyses. After a mean of 2-2.6 injection cycles, headache frequency was shown to decrease significantly after treatment with onabotulinumtoxinA (Hedge's g = 0.97, 95% CI 0.58-1.35; p < 0.0001), as did severity (Hedge's g = 1.24, 95% CI 0.55-1.94; p = 0.0005), with both estimates having a large effect size magnitude. A Class I parallel-group RCT of one injection series (155 U, 74 U, or placebo), powered to detect a change in 4 headache days per month, did not find outcome differences between the active and placebo treatment arms. A Class IV crossover RCT showed superiority of active (155 U) versus placebo injections. The remaining Class IV observational studies that were excluded from the meta-analyses all showed improved outcomes with onabotulinumtoxinA injections over time. No serious adverse events related to treatment occurred.

CONCLUSION

OnabotulinumtoxinA injections have established safety for use in children and adolescents with CM and are likely effective in reducing headache frequency and severity over time. However, in the absence of an adequately powered parallel-group RCT assessing the efficacy of multiple injection cycles, it remains unclear if this intervention is superior to placebo.

Analgesic effect of Botulinum toxin in neuropathic pain is sodium channel independent

Botulinum neurotoxin type A BoNT/A is used off-label as a third line therapy for neuropathic pain. However, the mechanism of action remains unclear. In recent years, the role of voltage-gated sodium channels (Nav) in neuropathic pain became evident and it was suggested that block of sodium channels by BoNT/A would contribute to its analgesic effect. We assessed sodium channel function in the presence of BoNT/A in heterologously expressed Nav1.7, Nav1.3, and the neuronal cell line ND7/23 by high throughput automated and manual patch-clamp. We used both the full protein and the isolated catalytic light chain LC/A for acute or long-term extracellular or intracellular exposure. To assess the toxin's effect in a human cellular system, we differentiated induced pluripotent stem cells (iPSC) into sensory neurons from a healthy control and a patient suffering from a hereditary neuropathic pain syndrome (inherited erythromelalgia) carrying the Nav1.7/p.Q875E-mutation and carried out multielectrode-array measurements. Both BoNT/A and the isolated catalytic light chain LC/A showed limited effects in heterologous expression systems and the neuronal cell line ND7/23. Spontaneous activity in iPSC derived sensory neurons remained unaltered upon BoNT/A exposure both in neurons from the healthy control and the mutation carrying patient. BoNT/A may not specifically be beneficial in pain syndromes linked to sodium channel variants. The favorable effects of BoNT/A in neuropathic pain are likely based on mechanisms other than sodium channel blockage and new approaches to understand BoNT/A's therapeutic effects are necessary.

Advances in diagnosis and treatment of vestibular migraine and the vestibular disorders it mimics

Dizziness is one of the most common chief complaints in both the ambulatory care setting and the emergency department. These symptoms may be representative of a broad range of entities. Therefore, any attempt at treatment must first start with determining the etiology. In this current perspective, we focus specifically on the diagnosis of and treatment of vestibular migraine, which is common and overlaps clinically with a variety of other diagnoses. We discuss the traditional treatments for vestibular migraine in addition to the recent explosion of novel migraine therapeutics. Because vestibular migraine can mimic, or co-exist with, a variety of other vestibular diseases, we discuss several of these disorders including persistent postural-perceptual dizziness, benign paroxysmal positional vertigo, post-concussive syndrome, Ménière's disease, and cerebrovascular etiologies. We discuss the diagnosis of each, as well as overlapping and distinguishing clinical features of which the reader should be aware. Finally, we conclude with evidence based as well as expert commentary on management, with a particular emphasis on vestibular migraine.

The effectiveness and predictors influencing the outcome of onabotulinumtoxinA treatment in chronic migraine: understanding from diverse patient profiles in a single session

Objective

This real-world study aimed to investigate how onabotulinumtoxinA affects the outcome of migraine, along with accompanying anxiety, depression, and bruxism among a group of patients with chronic migraine (CM) and define predictors of good response.

Methods

Patients diagnosed with CM who received onabotulinumtoxinA were included in this single-center, real-world retrospective cohort study. Monthly headache days (MHDs), monthly migraine days (MMDs), headache intensity (numeric rating scale-NRS) and headache characteristics were evaluated at baseline and 12 weeks post-treatment. Patient-reported outcome measures (PROMs) included Migraine Disability Assessment Scale (MIDAS), Headache Impact Test-6 (HIT-6) scores, 12-item Allodynia Symptom Checklist (ASC-12), Beck Anxiety Inventory (BAI) and Beck Depression Inventory (BDI). Response to onabotulinumtoxinA (% reduction in MHDs) and treatment-related adverse events (TRAEs) were also evaluated. OnabotulinumA was applied to the masseter muscles in patients complaining of bruxism.

Results

A total of 72 patients (mean ± SD age: 36.3 ± 8.5 years; 91.7% were female) diagnosed with CM were included. OnabotulinumtoxinA revealed significant decrease in median (IQR) MHDs [from 20(15-25) at baseline to 6(4-10), p < 0.001], MMDs [from 9(6-12) to 3(1-6), p < 0.001] and NRS [from 9(8-10) to 7(6-8), p < 0.001], and the MIDAS [from 54(30-81) to 16(7-24), p < 0.001], HIT-6 [from 67(65-69) to 58(54-64), p < 0.001], ASC-12 [from 6(1.5-9) to 2(0-9), p = 0.002], BAI [from 12(6.5-19) to 9(3-17), p < 0.001] and BDI [from 11(6.5-17) to 3(2-7) p < 0.001] scores at 12 weeks post-treatment. Patients complaining of bruxism received onabotulinumtoxinA injections in the first n = 27 (37.5%) and 12. week post-treatment n = 19 (70.4%) periods. Overall, 70.8% of patients responded (≥50% reduction in MHDs), while 29.2% did not (<50% reduction). Both groups showed similar characteristics in demographics, migraine history, baseline PROMs scores, comorbidities, and prior treatments.

Conclusion

OnabotulinumtoxinA is an effective treatment option that rapidly improves migraine outcomes, disability, and impact while also alleviating comorbid depression and/or anxiety. This study's noteworthy finding is that onabotulinumtoxinA is effective in a majority of CM patients, irrespective of their prior treatment history, migraine characteristics, or concurrent comorbidities. Furthermore, we identified no specific predictors for a favorable response to onabotulinumtoxinA. Applying onabotulinumtoxinA to the masseter muscles can relieve discomfort associated with concurrent bruxism; however, it does not impact migraine outcomes.

Neuromodulation Techniques for Headache Management

This narrative review aims to summarize evidence regarding the current utilization and future applications of neuromodulation in patients with headaches, with special attention paid to migraine and chronic cluster headache. A search was conducted in PubMed in August of 2023 to survey the current literature on neuromodulation for the treatment of headache. In total, the search yielded 1989 results, which were further filtered to include only systematic reviews published between 2022 to 2023 to capture the most up-to-date and comprehensive research on this topic. The citation lists of these articles were reviewed to find additional research on neuromodulation and supplement the results presented in this paper with primary literature. Research on the use of neuromodulation for the treatment of headache has predominantly focused on four neuromodulation techniques: peripheral nerve stimulation (PNS), transcranial magnetic stimulation (TMS), deep brain stimulation (DBS), and spinal cord stimulation (SCS). Outcome measures reported in this article include impact on migraine and headache frequency and/or pain intensity, adverse effects of the neuromodulation technique, and associated costs, when available. We found that neuromodulation has developed utility as an alternative treatment for both chronic cluster headaches and migraines, with a reduction in frequency and intensity of headache most elucidated from the articles mentioned in this review.

Botox in below knee amputation for the management of post-operative contracture: a systematic review

During the 1970s, scientists first used botulinum toxin to treat strabismus. While testing on monkeys, they noticed that the toxin could also reduce wrinkles in the glabella area. This led to its widespread use in both medical and cosmetic fields. The objective of the study was to evaluate the potential use of Botox in managing post-operative contracture after below-knee amputation. We conducted a systematic review In Pubmed, Cochrane Library, Embase, and Google Scholar using the MESH terms Botox, botulinum toxin, post-operative contracture, amputation, and below knee amputation. Our goal was to evaluate the potential use of Botox to manage post-operative contracture in patients who have undergone below-knee amputation. Our findings show evidence in the literature that Botox can effectively manage stump hyperhidrosis, phantom pain, and jumping stump, but no clinical trial has been found that discusses the use of Botox for post-operative contracture. Botox has been used in different ways to manage spasticity. Further studies and clinical trials are needed to support the use of Botox to manage this complication.

The Effect of OnabotulinumtoxinA on Headache Intensity and Number of Monthly Headache Days in Individuals with Chronic Migraine with Different Levels of Neck Disability

One of the treatment methods used in chronic migraine is OnabotulinumtoxinA. The effects of OnabotulinumtoxinA on headache intensity (HI) and number of monthly headache days (NMHD) in chronic migraine (CM) patients classified according to neck disability levels are unknown. Our aim was to investigate the effect of OnabotulinumtoxinA on the HI and the NMHD in individuals with CM with different levels of neck disability. One hundred sixteen patients were enrolled in the study. The OnabotulinumtoxinA protocol was administered as per Follow-the-Pain PREEMPT. The Neck Disability Index was used to evaluate neck disability. Primary outcome measures were headache intensity, assessed with the Visual Analogue Scale, and the number of monthly headache days recorded from patients' diaries. Secondary outcome measures were migraine disability, assessed with the Migraine Disability Assessment Test, and quality-of-life, assessed with the Headache Impact Test-6. All assessments were made at baseline and end of the treatment. The OnabotulinumtoxinA treatment showed a greater improvement effect in the number of monthly headache days (p = 0.000) and migraine disability (p = 0.000) parameters in the severe and complete disability groups. CM patients with complete and severe neck disability received the most benefit in reducing the NMHD at 3 months after OnabotulinumtoxinA treatment, but the HI decreased at a similar level in all neck disability groups.

Unusual herpetic reactivation in a young female following botox injection: a case report study

BACKGROUND

Botox injections are commonly used for cosmetic and therapeutic purposes because they temporarily paralyze muscles, reduce wrinkles, and alleviate certain medical conditions. Although generally considered safe and effective, Botox injections may cause potential complications. While herpes reactivation is more commonly associated with immunosuppressive therapies, such as chemotherapy or corticosteroid use, its association with Botox injection is poorly documented.

CASE PRESENTATION

A 33-year-old woman presented with progressive painful rashes and vesicles on her forehead, scalp, and right upper eyelid, accompanied by fever and malaise following a Botox injection to treat wrinkles. A positive Tzanck smear test result confirmed the diagnosis of herpes infection. The patient was treated with antiviral medication, and her symptoms gradually regressed over several days.

CONCLUSIONS

Although herpes reactivation is more commonly associated with immunosuppressive therapies, few cases of herpes zoster and herpes simplex following Botox injection have been reported. The pathogenesis of herpes reactivation following Botox injection is unclear; however, it has been hypothesized that the Botox protein is a potent antigen that may activate the cellular immune system, making it easier for the virus to reactivate. Healthcare providers should be aware of this potential complication and consider it when evaluating patients who present with painful rashes following Botox injections. In addition, individuals who want to receive Botox injections should be informed of this complication. The diagnosis of herpetic infection should be made promptly, and antiviral therapy should be initiated to minimize the risk of complications. Further research is needed to better understand the pathogenesis and risk factors for herpes following Botox injection and to develop strategies for preventing and managing this complication.

Botulinum toxin A decreases neural activity in pain-related brain regions in individuals with chronic ocular pain and photophobia

Introduction

To examine the effect of botulinum toxin A (BoNT-A) on neural mechanisms underlying pain and photophobia using functional magnetic resonance imaging (fMRI) in individuals with chronic ocular pain.

Methods

Twelve subjects with chronic ocular pain and light sensitivity were recruited from the Miami Veterans Affairs eye clinic. Inclusion criteria were: (1) chronic ocular pain; (2) presence of ocular pain over 1 week recall; and (3) presence of photophobia. All individuals underwent an ocular surface examination to capture tear parameters before and 4-6 weeks after BoNT-A injections. Using an event-related fMRI design, subjects were presented with light stimuli during two fMRI scans, once before and 4-6 weeks after BoNT-A injection. Light evoked unpleasantness ratings were reported by subjects after each scan. Whole brain blood oxygen level dependent (BOLD) responses to light stimuli were analyzed.

Results

At baseline, all subjects reported unpleasantness with light stimulation (average: 70.8 ± 32.0). Four to six weeks after BoNT-A injection, unpleasantness scores decreased (48.1 ± 33.6), but the change was not significant. On an individual level, 50% of subjects had decreased unpleasantness ratings in response to light stimulation compared to baseline ("responders," n = 6), while 50% had equivalent (n = 3) or increased (n = 3) unpleasantness ("non-responders"). At baseline, several differences were noted between responders and non-responders; responders had higher baseline unpleasantness ratings to light, higher symptoms of depression, and more frequent use of antidepressants and anxiolytics, compared to non-responders. Group analysis at baseline displayed light-evoked BOLD responses in bilateral primary somatosensory (S1), bilateral secondary somatosensory (S2), bilateral anterior insula, paracingulate gyrus, midcingulate cortex (MCC), bilateral frontal pole, bilateral cerebellar hemispheric lobule VI, vermis, bilateral cerebellar crus I and II, and visual cortices. BoNT-A injections significantly decreased light evoked BOLD responses in bilateral S1, S2 cortices, cerebellar hemispheric lobule VI, cerebellar crus I, and left cerebellar crus II. BoNT-A responders displayed activation of the spinal trigeminal nucleus at baseline where non-responders did not.

Discussion

BoNT-A injections modulate light-evoked activation of pain-related brain systems and photophobia symptoms in some individuals with chronic ocular pain. These effects are associated with decreased activation in areas responsible for processing the sensory-discriminative, affective, dimensions, and motor responses to pain.

Botulinum Neurotoxin Type a Injection Combined with Absorbable Punctal Plug Insertion: An Effective Therapy for Blepharospasm Patients with Dry Eye

Blepharospasm patients often have dry eye manifestations. Botulinum neurotoxin type A (BoNT-A) injection has been the main management for blepharospasm and absorbable punctal plug (APP) insertion is shown to be effective in the treatment of dry eye. However, there have been no studies investigating the combined treatment of BoNT-A and APP in blepharospasm patients with dry eye. In this retrospective study, 17 blepharospasm patients with dry eye treated by BoNT-A injection and 12 receiving BoNT-A plus APP treatment were enrolled. The efficacy was evaluated according to the Jankovic rating scale, Ocular Surface Disease Index (OSDI), fluorescein staining (FL), fluorescein tear break-up time (FBUT) and Schirmer I test (SIT). Both BoNT-A and BoNT-A+APP treatment effectively reduced the functional impairment of blepharospasm. At baseline, all the patients had high OSDI scores (BoNT-A group: 82.48 ± 7.37, BoNT-A+APP group: 78.82 ± 4.60, p = 0.112), but relatively low degrees of FL (BoNT-A group: 3.18 ± 1.01, BoNT-A+APP group: 3.50 ± 1.24, p = 0.466), FBUT (BoNT-A group: 1.71 ± 0.77, BoNT-A+APP group: 2.17 ± 0.58, p = 0.077) and SIT (BoNT-A group: 2.53 ± 0.99, BoNT-A+APP group: 3.17 ± 1.23, p = 0.153). After treatment, OSDI, FL, FBUT and SIT were all obviously restored in the two groups. When comparing the changing rates, only OSDI (BoNT-A group: -52.23% ± 15.57%, BoNT-A+APP group: -61.84% ± 9.10%, p = 0.047) and FL (BoNT-A group: -22.55% ± 25.98%, BoNT-A+APP group: -41.94% ± 14.46%, p = 0.016) showed significant differences between the two groups. This study suggests that OSDI is not applicable in the diagnosis of dry eye among blepharospasm patients. For blepharospasm patients with severe dry eye symptoms, especially those with fluorescein staining in the cornea, the combined treatment of BoNT-A and APP is more effective than using BoNT-A alone.

OnabotulinumtoxinA Treatment in Chronic Migraine: Investigation of Its Effects on Disability, Headache and Neck Pain Intensity

Neck disability and pain are frequently encountered problems in patients with chronic migraine (CM). The long-term stimuli of neurons in the trigeminocervical junction may explain this situation. OnabotulinumtoxinA (ONA) treatment is one of the proven treatments for CM; however, there is no study data on the efficacy of ONA treatment on neck disability and pain in CM patients. Therefore, we aimed to investigate the effect of ONA treatment on disability, neck pain and headache intensity in CM patients. One hundred thirty-four patients who met the inclusion criteria were included in the study. ONA treatment was administered at a dose of 195 U to 39 sites in total as per Follow-the-Pain PREEMPT protocol. The disability was evaluated with the Neck Disability Index and the Migraine Disability Assessment; pain intensity was evaluated with the Visual Analogue Scale; the monthly number of headache days were recorded; quality of life was evaluated with the Headache Impact Test. All assessments were recorded at baseline and 3 months after treatment. After the treatment, neck−migraine disabilities decreased from severe to mild for neck and moderate for migraine (p < 0.001). Neck pain and headache intensities decreased by almost half (p < 0.001). The median number of monthly headache days decreased from 20 days to 6 days (p < 0.000). The quality-of-life level decreased significantly from severe to substantial level (p < 0.001). According to our results, ONA treatment was effective in reducing neck-related problems in CM patients. Long-term follow-up results may provide researchers with more comprehensive results in terms of the treatment of chronic migraine−neck-related problems.

The Development of Psychiatric Illness and Chemoprophylaxis of Botulinum Toxin in Migraine: A Narrative Review

A migraine is not just a headache. It is an extremely prevalent neurological condition marked by periodic episodes of unilateral headache, with more than 10 million cases yearly. Migraine often begins at the age of puberty. It substantially impacts the brain and, consequently, psychiatric behavior linked with frequent migraine attacks that may be moderate to severe in intensity. A crucial aspect of migraine variability is comorbidity with other neurological diseases, vascular diseases, and mental illnesses. Psychiatric disorders related to migraine include anxiety disorders, panic disorder, bipolar disorder, depression, etc. It is also estimated that people suffering from migraine are about five times more likely to develop depression than others without migraine. The stimulus for migraine is stress, lack of sleep, skipped meal or fasting, visual stimulation due to high intensity of light, auditory stimulus due to noise, and olfactory stimulus due to a pungent smell. A majority of patients suffer from migraine attacks triggered by noise, some due to visual stimulation, and a few due to perfumes or other odors that trigger their migraine. Diagnosis of this is primarily dependent on history taking and clinical evaluation. Migraine can be classified depending on whether an aura is present or absent. It can further be divided based on the frequency of headaches into episodic migraine or chronic migraine, which may be determined by the duration of the headache. The development of migraine is influenced by both genetics and the environment. It has a detrimental effect on children's quality of life. A comprehensive analysis of psychiatric illnesses in migraine contributes to early diagnosis and proper treatment of the disease. Also, having a healthy lifestyle (including exercise, a balanced diet, and enough sleep) seems to prevent and improve the condition. Headache in migraine is resistant to medical treatment but responds well to botulinum toxin. This review primarily focuses on the psychiatric issues like depression and anxiety that often accompany migraine. The article also highlights the effects of botulinum toxin on migraine.

How Does Botulinum Toxin Inhibit Itch?

Two decades after reports of the anti-pruritic effects of botulinum neurotoxins (BoNTs), there is still no approved product for the anti-itch indication of BoNTs, and most clinical case reports still focus on the off-label use of BoNTs for various itchy conditions. Few randomized clinical trials have been conducted with controversial results, and the beneficial effects of BoNTs against itch are mainly based on case studies and case series. These studies are valuable in presenting the potential application of BoNTs in chronic pruritic conditions, but due to the nature of these studies, they are categorized as providing lower levels of evidence or lower grades of recommendation. To obtain approval for the anti-pruritic indication of BoNTs, higher levels of evidence are required, which can be achieved through conducting large-scale and well-designed studies with proper control groups and established careful and reliable primary and secondary outcomes. In addition to clinical evidence, presenting the mechanism-based antipruritic action of BoNTs can potentially strengthen, accelerate, and facilitate the current efforts towards further investments in accelerating the field towards the potential approval of BoNTs for itchy conditions. This review, therefore, aimed to provide the state-of-the-art mechanisms underlying the anti-itch effect of BoNTs from basic studies that resemble various clinical conditions with itch as a hallmark. Evidence of the neuronal, glial, and immune modulatory actions of BoNTs in reducing the transmission of itch are presented, and future potential directions are outlined.

Artificial Intelligence and Migraine: Insights and Applications

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