Botulinum toxin treatment of cephalalgia alopecia increases substance P and calcitonin gene-related peptide-containing cutaneous nerves in scalp

Intradermal Injection in Balding Region Versus Intramuscular Injection in Surrounding Muscles: A Split-Scalp, Randomized Trial on BoNT for Androgenetic Alopecia

INTRODUCTION

Recent advancements in androgenetic alopecia (AGA) treatment have highlighted the efficacy of botulinum toxin (BoNT). However, inconsistencies in injection sites and depths warrant attention. It remains unclear which injection strategy is most beneficial for patients.

METHODS

This split-scalp randomized controlled trial divided each enrolled participant's scalp along the midline: one side was randomized to receive intramuscular BoNT injections in the surrounding muscles, while the other side received intradermal BoNT injections directly into the balding areas. This study evaluated the impact of treatment on hair density and diameter through trichoscopic examinations conducted at baseline and 12 weeks post treatment. Additionally, assessments of pain and overall safety were integrated into the study protocol.

RESULTS

Twenty-nine patients completed the study, with significant improvements in hair density observed in the intramuscular injection group compared to the intradermal group (p < 0.001). Both groups exhibited increases in hair diameter, but no significant difference was found between the two methods (p = 0.433). Pain evaluation revealed that intradermal injections in balding areas were more painful than intramuscular injections (p = 0.036), with no severe adverse reactions reported except for a single case of alopecia areata following injection.

CONCLUSION

Our research revealed that both BoNT injection strategies enhanced hair diameter 12 weeks post-treatment, with intramuscular injections significantly improving hair density more effectively. Despite the promising outcomes, the variability in patient responses underscores the necessity for personalized approaches and further research to refine injection protocols for optimized efficacy and safety.

TRIAL REGISTRATION NUMBER

ChiCTR2400080190.

Botulinum Toxin A for Hair Loss Treatment: A Systematic Review of Efficacy, Safety, and Future Directions

Background

Hair loss is a common condition with significant impact globally, yet its treatment efficacy and safety remain debated. Botulinum toxin A (BoNT-A) has emerged as a potential therapeutic option, but a comprehensive review on this topic is lacking.

Objective

This review critically evaluates the current evidence on BoNT-A for hair loss treatment, highlighting the gaps in previous reviews and providing a comprehensive analysis of its efficacy, safety, and future prospects.

Methods

A systematic search of electronic databases identified relevant studies published up to September 2022.

Results

Prior reviews primarily focused on androgenetic alopecia and lacked the evaluation of other alopecia types and underlying mechanisms. Our review addresses this gap, incorporating a broader spectrum of hair loss conditions. Mechanisms of BoNT-A in hair growth modulation, potential side effects, and future research directions are discussed.

Conclusion

This review adds to the existing body of knowledge by providing a comprehensive evaluation of BoNT-A in hair loss treatment. The findings will serve as a foundation for further research and guide clinicians in making informed decisions, ultimately improving the outcomes and quality of life for individuals suffering from hair loss.

Botulinum Toxin for Scalp Conditions: A Systematic Review

BACKGROUND

Many reports have described the use of botulinum toxin (BTX) in the treatment of scalp conditions, but no studies have synthesized these collective findings.

OBJECTIVE

We conducted a systematic review to summarize the scalp conditions for which treatment with BTX has been described.

METHODS

We searched PubMed/MEDLINE and Scopus for articles in English published before November 1, 2022, using the keywords "hair" or "scalp" and BTX-related search terms. Articles that described patients who received injections of BTX for the management of scalp conditions were included.

RESULTS

Twenty-four original articles (12 case reports, 9 clinical trials, and 3 case series) were identified that described 309 patients with a scalp condition treated with BTX. Androgenetic alopecia, craniofacial hyperhidrosis, and scalp hyperseborrhea had the most robust data supporting the clinical efficacy of BTX.

CONCLUSION

The current quality of evidence is highly variable and, for many conditions, limited to small observational studies. Botulinum toxin may be a promising therapeutic option for patients with various scalp conditions, but future studies are needed to better understand its efficacy and safety.

Botulinum Toxin Use for Modulating Neuroimmune Cutaneous Activity in Psoriasis

Psoriasis is a complex immune-mediated inflammatory disorder that generates enormous interest within the scientific communities worldwide, with new therapeutic targets being constantly identified and tested. Despite the numerous topical and systemic medications available for the treatment of psoriasis, alternative therapies are still needed for the optimal management of some patients who present with localized, resistant lesions. Novel insights into the contribution of cutaneous neurogenic inflammation in the pathogenesis of psoriasis have yielded exciting new potential roles of nerve-targeting treatments, namely botulinum toxin type A (BoNT-A), for the management of this disease. This paper aims to review the existing literature on knowledge regarding the potential role of BoNT-A in psoriasis treatment, with a focus on its ability to interfere with the immunopathogenetic aspects of psoriatic disease. Furthermore, in our paper, we are also including the first report of psoriatic lesions remission following local BoNT-A injections that were administered for treating upper limb spasticity, in a patient that concomitantly suffered from psoriasis and post-stroke spasticity.

Toxicology and pharmacology of botulinum and tetanus neurotoxins: an update

Tetanus and botulinum neurotoxins cause the neuroparalytic syndromes of tetanus and botulism, respectively, by delivering inside different types of neurons, metalloproteases specifically cleaving the SNARE proteins that are essential for the release of neurotransmitters. Research on their mechanism of action is intensively carried out in order to devise improved therapies based on antibodies and chemical drugs. Recently, major results have been obtained with human monoclonal antibodies and with single chain antibodies that have allowed one to neutralize the metalloprotease activity of botulinum neurotoxin type A1 inside neurons. In addition, a method has been devised to induce a rapid molecular evolution of the metalloprotease domain of botulinum neurotoxin followed by selection driven to re-target the metalloprotease activity versus novel targets with respect to the SNARE proteins. At the same time, an intense and wide spectrum clinical research on novel therapeutics based on botulinum neurotoxins is carried out, which are also reviewed here.

The Effect of Botulinum Toxin on Hair Follicle Cell Regeneration Under Continuous Stress Conditions: a Pilot Animal Study

We analyzed the effect of botulinum toxin (BTX) type A on the regeneration of hair follicle cells under continuous stress conditions. Thirty 6-week-old C57BL/6 mice were used, and hair loss was induced on their backs (10 control (CTL) mice, reared under normal conditions without stress; 10 mice, exposed to continuous stress (STRESS) by fixing in an enclosed space; 10 BTX + STRESS mice, injected subcutaneously with 1 IU of BTX (0.1 cc) where the hair follicles were removed under the same stress conditions). There was less hair growth in the STRESS and BTX + STRESS groups compared to that in the CTL group at 2 weeks. At 3 weeks, the telogen stage was mainly observed in the STRESS group whereas the anagen stage was observed in the CTL and BTX + STRESS groups. A substantial increase in terminal deoxynucleotidyl transferase dUTP nick end labeling-positive cells was observed in the STRESS group compared to that in the CTL and BTX + STRESS groups. Substance P (SP) immunoreactivity cell levels increased in the STRESS group at 2 and 3 weeks compared to those in the BTX + STRESS group. SP expression increased at 2 and 3 weeks in the STRESS group compared to that in the CTL and BTX + STRESS groups. A delay in the regeneration cycle of the hair follicle cells occurred when stress was applied, and an almost normal regeneration cycle occurred when BTX was injected subcutaneously. Therefore, BTX may be a positive indicator for hair loss treatment.

Therapeutic Use of Botulinum Neurotoxins in Dermatology: Systematic Review

Botulinum toxin is a superfamily of neurotoxins produced by the bacterium Clostridium Botulinum with well-established efficacy and safety profile in focal idiopathic hyperhidrosis. Recently, botulinum toxins have also been used in many other skin diseases, in off label regimen. The objective of this manuscript is to review and analyze the main therapeutic applications of botulinum toxins in skin diseases. A systematic review of the published data was conducted, following Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Botulinum toxins present several label and off-label indications of interest for dermatologists. The best-reported evidence concerns focal idiopathic hyperhidrosis, Raynaud phenomenon, suppurative hidradenitis, Hailey–Hailey disease, epidermolysis bullosa simplex Weber–Cockayne type, Darier’s disease, pachyonychia congenita, aquagenic keratoderma, alopecia, psoriasis, notalgia paresthetica, facial erythema and flushing, and oily skin. Further clinical trials are still needed to better understand the real efficacy and safety of these applications and to standardize injection and doses protocols for off label applications.

Alternative Clinical Indications of Botulinum Toxin

Botulinum toxin type A (BoNTA) is a powerful neurotoxin that inhibits acetylcholine release from presynaptic vesicles. The potency and safety profile of BoNTA grant the toxin vast therapeutic potential. It has been used off-label for a variety of dermatologic conditions. This review aims to analyze published literature regarding the benefits and risks of the off-label use of BoNTA beyond facial lines, including eccrine hidrocystomas, enlarged pores, keloids and hypertrophic scars, hidradenitis suppurativa, hyperhidrosis, masseter muscle hypertrophy, and salivary gland hypertrophy, among others. A MEDLINE search from January 2000 to December 2019 was conducted on the off-label uses of botulinum toxin in dermatology.

Botulinum Toxin Off-Label Use in Dermatology: A Review

BACKGROUND

Botulinum toxin is a neurotoxin produced by the bacterium Clostridium botulinum which causes a flaccid muscle paralysis. It is currently used for aesthetic treatments and in the focal hyperhidrosis. Recently, botulinum toxin has also been used experimentally in many other dermatological conditions with good results.

OBJECTIVE

To review and analyze the possible botulinum toxin off-label applications published.

METHODS

A retrospective review of the published data was conducted.

CONCLUSIONS

this potent drug can lead to several off-label indications of interest for dermatologists. Further clinical trials are still needed to better understand the real efficacy and safety of these applications and to standardize injection and dose protocols.

Botulinum toxin type A for the treatment of trigeminal neuralgia: results from a randomized, double-blind, placebo-controlled trial

AIM

To investigate the efficacy, safety and tolerability of intradermal and/or submucosal administration of botulinum toxin type A (BTX-A) for patients with trigeminal neuralgia (TN).

METHODS

In this randomized, double-blind, placebo-controlled study, 42 TN patients were randomly allocated into two groups, namely, intradermal and/or submucosal injection of BTX-A (75 U/1.5 mL; n = 22) or saline (1.5 mL; n = 20) in the skin and/or mucosa where pain was experienced. The primary endpoints were pain severity (assessed by the visual analogue scale) and pain attack frequency per day. The secondary endpoint was the patient's overall response to treatment, assessed using the Patient Global Impression of Change scale. Patients with ≥ 50% reduction in mean pain score at week 12 were defined as responders.

RESULTS

A total of 40 patients completed the study. BTX-A significantly reduced pain intensity at week 2 and pain attack frequency at week 1. The efficacy was maintained throughout the course of the study. More BTX-A treated patients reported that pain had improved by the end of the study. Significantly more responders were present in the BTX-A group (68.18%) than in the placebo group (15.00%). BTX-A was well tolerated, with few treatment-related adverse events.

CONCLUSIONS

BTX-A may be an efficient, safe and novel strategy for TN treatment.

Botulinum toxin treatment of secondary headaches and cranial neuralgias: a review of evidence

BACKGROUND

Recent scientific data support an effect of botulinum neurotoxin (BoNT) on pain and headache.

OBJECTIVE

We sought to conduct a systematic review of BoNT in the secondary headaches and cranial neuralgias.

METHODS

MEDLINE, EMBASE, Cochrane, ClinicalTrials.gov and reference lists were searched up to December 2010 to identify all relevant publications.

RESULTS

Only two papers were rated as highest evidence (Level 1). The absolute majority (30/38, 79%) of identified publications yield only low evidence (Level 4).

DISCUSSION

No treatment recommendations of Grade A or Grade B can be made based on available research. Grade C treatment recommendations in support of BoNT can be made for chronic headache attributed to whiplash injury, cephalalgic alopecia areata, headache and facial pain in blepharospasm, trigeminal neuralgia, occipital neuralgia and nummular headache. As a result of studies being troublingly inconsistent or inconclusive, only the weakest rank of recommendations (Grade D) can be made for using BoNT in medication overuse headache, cervicogenic headache, headache attributed to craniocervical dystonia, pain in masticatory hyperactivity and headache or facial pain attributed to temporomandibular disorder.

CONCLUSION

At present, BoNT cannot be firmly recommended as an evidence-based treatment in secondary headaches or cranial neuralgias.