Complications of Botulinum toxin A: An update review

Dysphagia and Muscle Weakness Caused by Botulinum Toxin Poisoning after Cosmetic Injection: Three Case Reports and Clinical Warnings

Botulinum toxin (BoNT), a neurotoxic protein produced by Clostridium botulinum, is widely used for cosmetic and therapeutic purposes, including managing muscle hyperactivity, movement disorders, and chronic migraines by blocking acetylcholine release at neuromuscular junctions. While generally safe, it can cause localized adverse effects (erythema, ptosis, pain) and rare systemic complications (dysphagia, dysarthria, respiratory distress), particularly with improper dosing. From August 2024, This case report presents three female patients, aged 25, 50, and 49, in the Affiliated Hospital of Yunnan University, who experienced severe complications following the injection of botulinum toxin. The first patient, developed dysarthria and dysphagia 18 days post-injection, with a history of administration in northern Myanmar. The second patient, reported similar symptoms 3 days after a lesser dosage was injected into her masseter muscles. The third patient, exhibited fatigue and difficulty in eye opening and swallowing 7 days after receiving botulinum toxin. The symptoms of all patients were significantly improved after receiving symptomatic treatment in our hospital. The three cases presented are significant as they highlight the potential complications arising from botulinum toxin injections, particularly when used for cosmetic purposes. Botulinum toxin, though effective for cosmetic and therapeutic applications, carries risks of localized (muscle weakness, ptosis, bone loss) and systemic complications (generalized weakness, botulism), particularly near critical anatomical structures. Dysphagia and dysarthria, observed in cases post-injection, likely arise from toxin diffusion causing unintended muscle impairment. Treatment outcomes vary, with supportive care or invasive interventions often yielding limited improvement, highlighting management challenges. Clinicians must prioritize patient education, informed consent, and vigilant post-treatment monitoring for neurological symptoms. Future guidelines should standardize safe administration practices-optimizing dosage, injection sites, and follow-up-while enhanced practitioner training and multidisciplinary approaches are critical to mitigating risks and improving outcomes. This underscores the imperative for heightened clinical awareness and robust safety protocols to safeguard patient welfare.

Botulinum Toxin Use in the Upper Third of the Face

Botulinum toxin (BTX) is one of the most frequent procedures performed in the United States for facial rhytids. It has become a mainstay aesthetic treatment of the upper third of the face. In addition to aesthetic indications, there are a multitude of functional disorders for which BTX has proved effective. Patient evaluation and selection are critical components to treatment success. A thorough understanding of patient anatomy is critical for prevention of complications when using BTX. The use of neuromodulators in the upper third of the face is continually evolving and its indications continue to expand.

Urticaria-Like Hypersensitivity Reaction Following Botulinum Toxin Injection: A Case Report of Possible Interaction with β-Lactam Antibiotics

Botulinum toxin serotype A (BTX-A) is commonly used for treating facial dynamic wrinkles. The clinical safety of BTX-A has been proven, and it has few side effects; despite this, BTX-A has the potential to cause an allergic reaction. This case raises concerns about a possible interaction between botulinum toxin serotype A (CBTX-A) and β-lactam antibiotics, contributing to the limited literature on hypersensitivity reactions. Herein, we described the case of a 35-year-old woman who was injected with Chinese botulinum toxin serotype A (CBTX-A) to treat crow's feet. The treatment was performed after the patient had taken cefprozil for an upper respiratory tract infection. Subsequently, the patient developed urticaria-like symptoms that completely resolved within 24 hours after administration of antihistamines. This case emphasises the need for careful medication history review before botulinum toxin administration, especially in patients receiving β-lactam antibiotics, as hypersensitivity reactions may occur.

The etiologic and pathogenic spectrum of exposure keratopathy: Diagnostic and therapeutic implications

Exposure keratopathy (EK) is an underestimated ocular surface disorder that involves multiple underlying pathophysiologic mechanisms. It results from an exposed cornea due to different causes of eyelid insufficiency or blinking dysfunction, ocular globe protrusion, a negative orbital vector, and diverse contributing factors leading to impaired ocular surface homeostasis and the potential for vision loss. EK can be congenital, acquired, or induced, and various risk factors predispose patients to corneal exposure. These causes can be grouped into those related to proptosis and eyelid malformations, malfunctioning, or acquired deformity. If detected early, EK offers a range of effective treatment options. The superficial punctate keratitis and dryness of the cornea's lower third can be successfully treated at the initial stages; however, if left untreated, EK can progress to extensive epithelial erosion, persistent epithelial defects, stromal melting, vascularization, squamous metaplasia, and opportunistic infections, leading to significant visual loss. Different and varied treatment modalities, including medical and surgical, are available for patients with EK, depending on the disease stage, the underlying mechanism, and the cause. We examine the risk factors, causes, and range of pathologies associated with EK. Exploring the mechanisms that contribute to the development of the disorder's clinical manifestations provides valuable insights that can help clinicians detect and diagnose the disease promptly and plan appropriate targeted treatments.

Pioneering pain management with botulinum toxin type A: From anti-inflammation to regenerative therapies

In the present paper, a comprehensive review was conducted to evaluate the performance of botulinum toxin type A (BTX-A) in managing various types of pain, including myofascial, muscular temporomandibular joint pain, orofacial pain, chronic migraines, and more. Firstly, the mechanism of action and anti-inflammatory effects of BTX-A was introduced. Following this, recent advancements in BTX-A applications were discussed, with an emphasis on emerging combination therapies, regenerative medicine, and personalized treatment strategies. Unlike previous reviews, this study explored a broader spectrum of pain conditions and highlighted BTX-A's versatility and potential as a long-term, minimally invasive pain management option. Additionally, the importance of tailoring BTX-A treatment was emphasized through the integration of biomarkers, genetic factors, and optimized dosing regimens to enhance efficacy and minimize side effects. Novel combinations with regenerative therapies, such as stem cells and tissue engineering, were identified as promising avenues for joint and nerve repair, providing both symptomatic relief and tissue regeneration. Furthermore, digital health tools and artificial intelligence were suggested as innovative approaches to monitor treatment responses and optimize dosing protocols in real-time, advancing personalized pain management. Overall, this review underscores BTX-A's potential in comprehensive and patient-centered pain management and offers recommendations to guide future studies in optimizing BTX-A therapy.

The Esthetic Use of Botulinum Toxins in Cancer Patients: Providing a Foundation for Future Indications

Advances in oncological treatments have improved the survival rates of cancer patients but have often resulted in significant physical changes that negatively impact their self-esteem and psychological well-being. Cancer patients frequently ask esthetic practitioners to perform procedures to address such changes. However, practitioners often hesitate to satisfy such requests due to lacking guidelines or recommendations. The use of botulinum toxins (BoNTs) for esthetic purposes has shown significant promise in improving the quality of life for cancer patients. This review explores the broad application of BoNTs in many medical branches, focusing on oncology. A substantial amount of literature shows that BoNTs are safe and effective as a type of adjunctive therapy compared to classical cancer treatments. We provide our expert opinion that the use of BoNTs for esthetic purposes is safe for cancer patients and even recommended for those whose mood is influenced by the worsening of their physical appearance. Careful patient selection and interdisciplinary collaboration are essential to the safe integration of BoNTs into cancer care.

Adverse effects of the aesthetic use of botulinum toxin and dermal fillers on the face: a narrative review

OBJECTIVE

To evaluate the adverse effects of facial aesthetic treatments using botulinum toxin and biomaterial implants.

METHODS

The bibliographic research for this narrative review considered articles published in journals from the Medline, Pubmed, Embase and Lilacs databases with the following terms: "dermal fillers AND complications, vascular complications AND dermal fillers, adverse reaction, AND toxin botulinum and adverse reaction AND dermal fillers". Inclusion criteria were articles available in English on adverse events with the aesthetic use of botulinum toxin and dermal fillers/biostimulators.

RESULTS

The demonstration of complications increases simultaneously with the progressive performance of facial aesthetic procedures. Quantitative statistics of the procedures and the countries that use them are skillfully classified, as well as the prosperity trends of these procedures. Complications do not receive the same relevance. There is a deficiency in dissemination of the information by the scientific community, or in other words, there is a publication bias in favor of successful results as opposed to adverse events.

CONCLUSION

The lack of knowledge about complications arising from so widely publicized and performed procedures prevents the development of evidence-based guidelines. Complications in aesthetic procedures have become a public health problem, an epidemic that occurs under the supervision of health authorities. Mandatory reporting of adverse events occurring in aesthetic procedures that require medical care aims to fill this gap. With reliable and technical data, it will be possible to identify the causes and perform interventions capable of minimizing irreversible sequelae and deaths. Complications should be promptly recognized by the dermatologist so that, when possible, they can be reversed or adequately managed.

Botulinum toxin treatment for hemifacial spasm: harmonising neurological and aesthetic outcomes

Hemifacial spasm (HFS) represents a challenging cranial movement disorder primarily affecting the facial nerve innervated muscles, with significant prevalence among Asians. Botulinum toxin type A (BoNT/A) injections, established as a primary therapeutic intervention since FDA approval, offer considerable effectiveness in alleviating spasms, albeit accompanied by challenges such as temporary effects and potential adverse events including facial asymmetry. This comprehensive review underscores the crucial need for harmonising neurological benefits and aesthetic outcomes in HFS management. The discussion delves into the interplay between facial aesthetics and neurological objectives in BoNT/A injections, emphasising precise techniques, dosages, and site considerations. Distinct aspects in neurological and aesthetic domains are also examined, including detailing the targeted muscles and injection methodologies for optimal therapeutic and aesthetic results. Importantly, evidence regarding various BoNT/A formulations, recommendations, and reconstitution guidelines in both neurology and aesthetics contexts are provided, along with a schematic approach outlining the stepwise process for BoNT/A injection in HFS treatment, addressing critical areas such as orbicularis oculi muscle sites, eyebrow correction strategies, mid- and lower-face considerations, contralateral injection sites, and post-injection follow-up and complication management. By highlighting the culmination of neurological efficacy and facial esthetics in BoNT/A treatment for HFS patients, this review proposes a holistic paradigm to achieve balanced symptomatic relief and natural aesthetic expression, ultimately enhancing quality of life for individuals grappling with HFS.

Rare and novel complications of botulinum neurotoxin type A and dermal filler injections

Botulinum neurotoxin type A (BoNTA) and filler injection procedures usually provide predicted outcomes with a low incidence of complications. Most of the complications after these procedures have been extensively discussed. In this study, we report on these injectables' less well-known, recently reported, and novel complications and attempt to clarify the underlying mechanisms. Counterfeit or mishandled BoNTA has been associated with botulism. BoNTA has been linked to uncommon complications, including morphea-like lesions, nontuberculous mycobacterial infections, vascular occlusion, and pseudoaneurysm of the superficial temporal artery. Unusual complications from filler injection include nonscarring alopecia, intraoral necrosis, nontuberculous mycobacterial infections, xanthelasma-like reactions, intracranial perforation, and pneumosinus dilatans. Post-BoNTA injection nodules and filler infection from bone destruction due to cocaine use are new complications. These complications pose a challenge for diagnosis and treatment. This publication aims to assist in promptly identifying and managing these rare and novel complications when necessary.

Effectiveness of 0.3% Hyaluronic Acid Eye Drops for Benign Essential Blepharospasm and Hemifacial Spasm with Botulinum Toxin-induced Dry Eye

Background

This study evaluates the effectiveness of 0.3% hyaluronic acid (HA) eye drops in patients receiving concurrent botulinum toxin (BoNT) injections for benign essential blepharospasm (BEB) or hemifacial spasm (HFS).

Methods

This randomized controlled cross-over trial study involved 14 patients with BEB and 33 patients with HFS randomized into two groups (early treatment and deferred treatment) for 3 months of treatment with 0.3% HA eye drops. Data collected at baseline, 3 months, and 6 months included Blepharospasm Severity Scale (BSS) score in patients with BEB; Samsung Medical Class Grading Scale score in patients with HFS; and dry eye symptoms, lower eyelid tear meniscus height (TMH), tear breakup time (TBUT), and corneal fluorescein staining in both groups.

Results

After 3 months of 0.3% HA instillation, patients with BEB in both groups showed significant improvement in BSS, TMH, TBUT, and the amelioration of subjective dry eye symptoms and corneal staining (P < 0.05). However, discontinuation of 0.3% HA eye drops worsened BSS, TMH, and TBUT. Patients with HFS also experienced significant improvement in Samsung Medical Class score, subjective dry eye symptoms, and objective corneal findings (P < 0.05).

Conclusions

Treatment with 0.3% HA eye drops led to significant improvement in spasm severity, and dry eye parameters, after 3 months of instillation in patients with BEB or HFS during concurrent treatment with BoNT injections. The 0.3% HA eye drops were safe and might serve as an add-on treatment for symptom improvement.

Ultrasound-Guided Botulinum Neurotoxin Injection for Alleviating Cricopharyngeus Muscle Spasticity: A Cadaveric Feasibility Study with Nerve Ending Analysis

Botulinum neurotoxin (BNT) injection into the cricopharyngeus muscle (CPM) under ultrasound (US) guidance is a minimally invasive technique performed to relieve cricopharyngeal dysphagia by reducing CPM spasticity. This technique is basically accessible only to both lateral sides of the CPM. This cadaveric study aimed to evaluate whether US-guided injection could effectively deliver BNT to abundant areas of gross nerve endings within the CPM. We utilized a newly modified Sihler's staining method to identify regions with abundant neural endings within the CPM while preserving the three-dimensional morphology of the muscle in 10 sides of 5 fresh cadavers. A mixture of 0.2 mL dye was injected into the 16 sides of CPM under US guidance in 8 cadavers. Nerve endings were abundant in posterolateral areas of the CPM; the injected dye was identified at the posterolateral area on 12 sides (12/16 side, 75%) without diffusion into the posterior cricoarytenoid muscle. The injection failed on four sides (two sides of the prevertebral fascia and two sides of the esophagus below the CPM). These results suggest that US-guided injection could be a feasible technique as it can deliver BNT to the most abundant nerve distribution areas within the CPM in most cases.

Localisation of the centre of the highest region of muscle spindle abundance of anterior forearm muscles

The centre of the highest region of muscle spindle abundance (CHRMSA) in the intramuscular nerve-dense region has been suggested as the optimal target location for injecting botulinum toxin A to block muscle spasms. The anterior forearm muscles have a high incidence of spasticity. However, the CHRMSA in the intramuscular nerve-dense region of the forearm anterior muscle group has not been defined. This study aimed to accurately define the body surface position and the depth of CHRMSA in an intramuscular nerve-dense region of the anterior forearm muscles. Twenty-four adult cadavers (57.7 ± 11.5 years) were included in this study. The curved line close to the skin connecting the medial and lateral epicondyles of the humerus was designated as the horizontal reference line (H line), and the line connecting the medial epicondyle of the humerus and the ulnar styloid was defined as the longitudinal reference line (L line). Modified Sihler's staining, haematoxylin-eosin staining and computed tomography scanning were employed to determine the projection points (P and P') of the CHRMSAs on the anterior and posterior surfaces of the forearm. The positions (PH and PL) of point P projected onto the H and L lines, and the depth of each CHRMSA, were determined using the Syngo system. The PH of the CHRMSA of the ulnar head of pronator teres, humeral head of pronator teres, flexor carpi radialis, palmaris longus, flexor carpi ulnaris, ulnar part of flexor digitorum superficialis, radial part of flexor digitorum superficialis, flexor pollicis longus, ulnar part of flexor digitorum profundus, radial portion of flexor digitorum profundus and pronator quadratus muscles were located at 42.48%, 45.52%, 41.20%, 19.70%, 7.77%, 25.65%, 47.42%, 53.47%, 12.28%, 38.41% and 51.68% of the H line, respectively; the PL were located at 18.38%, 12.54%, 28.83%, 13.43%, 17.65%, 32.76%, 57.32%, 64.12%, 20.05%, 45.94% and 88.71% of the L line, respectively; the puncture depths were located at 21.92%, 27.25%, 23.76%, 18.04%, 15.49%, 31.36%, 26.59%, 41.28%, 38.72%, 45.14% and 53.58% of the PP' line, respectively. The percentage values are the means of individual values. We recommend that the body surface puncture position and depth of the CHRMSA are the preferred locations for the intramuscular injection of botulinum toxin A to block anterior forearm muscle spasms.

Cosmetic Treatment Using Botulinum Toxin in the Oral and Maxillofacial Area: A Narrative Review of Esthetic Techniques

Botulinum toxin (BoNT) is an anaerobic rod-shaped-neurotoxin produced by Clostridium botulinum, that has both therapeutic and lethal applications. BoNT injection is the most popular cosmetic procedure worldwide with various applications. Patients with dynamic wrinkles in areas such as the glabella, forehead, peri-orbital lines, nasal rhytides, and perioral rhytides are indicated. Excessive contraction of muscles or hyperactivity of specific muscles such as bulky masseters, cobble stone chins, gummy smiles, asymmetric smiles, and depressed mouth corners can achieve esthetic results by targeting the precise muscles. Patients with hypertrophic submandibular glands and parotid glands can also benefit esthetically. There are several FDA-approved BoNTs (obabotuli-numtoxinA, abobotulinumtoxinA, incobotulinumtoxinA, letibotulinumtoxinA, prabotulinumtox-inA, daxibotulinumtoxinA, rimbotulinumtoxinB) and novel BoNTs on the market. This paper is a narrative review of the consensus statements of expert practitioners and various literature on the injection points and techniques, highlighting both the Asian and Caucasian population separately. This paper can serve as a practical illustrative guide and reference for optimal, safe injection areas and effective doses for application of BoNT in the face and oral and maxillofacial area. The history of BoNT indications, contraindications, and complications, and the merits of ultrasonography (US)-assisted injections are also discussed.

Locking the line of convergence by botulinum toxin type A for the treatment of dynamic forehead wrinkles

BACKGROUND

Treatment of horizontal forehead lines with botulium toxin type A is a common procedure that helps achieve a youthful and rejuvenated look. Adequate knowledge of the anatomy and an individualized treatment approach is the key to successful treatment outcome.

AIM

To evaluate the cosmetic outcome following treatment of dynamic forehead wrinkles by locking the line of convergence using botulinum toxin type A.

PATIENTS AND METHODS

Fifty female patients with dynamic forehead wrinkles were included. The line of convergence was identified, and injection points were determined. Patients received injections of botulinum toxin type A in the upper part of the frontalis along the line of convergence. Patients were evaluated before injection and the response was evaluated after 2 weeks and after 3 months of injection.

RESULTS

Post-treatment significant decrease in dynamic wrinkle scale was detected. The distance between the medial and lateral canthi and their corresponding lower brow margins on maximum brow elevation was also significantly decreased after treatment. Meanwhile, the validated brow positioning score revealed no significant change in the resting brow position when pre-and post-treatment scores were compared.

CONCLUSIONS

Treating forehead wrinkles by injecting botulinum toxin along the line of convergence is an effective technique that requires less overall amount of toxin, improves the appearance of the wrinkles and minimizes the risk of development of side effects.

Long‐pulsed Nd: YAG laser (1064 nm) versus intralesional botulinum toxin type (A) in acne vulgaris therapy: a split face study

BACKGROUND

Acne can be considered more than a cosmetic concern due to its large impact on patients' quality of life. There are various therapeutic options for inflammatory acne, but inconvenience and undesirable side effects prompted a search for more acceptable treatments. This study aimed to compare the clinical efficacy and safety of long-pulsed Nd: YAG laser 1064 nm versus intralesional botulinum toxin type-A (BTX-A) in inflammatory acne therapy.

METHODS

A prospective randomized split-face comparative study involved 30 patients with inflammatory acne. Each patient received long-pulsed Nd: YAG 1064 nm laser on one side, and intralesional BTX-A on the other side, monthly until improvement or maximum three sessions. Cases were assessed by acne lesions counting and grading of severity by Investigator's Global Assessment of acne (IGAs) at baseline, each session, and after 3 months follow-up.

RESULTS

A highly statistically significant improvement in lesions count and IGAs for both sides was observed, with statistically non-significant difference between both sides at end of treatment sessions. While, after 3 months follow-up, there was a more significant improvement at laser side.

CONCLUSION

Both long-pulsed Nd: YAG laser 1064 nm and intralesional BTX-A are safe and effective for acne therapy. Nd-YAG laser has a more prolonged efficacy and lower recurrence rate than intralesional BTX-A.

Serotype Features of 17 Suspected Cases of Foodborne Botulism in China 2019-2022 Revealed by a Multiplex Immuno-Endopep-MS Method

Diagnosis of botulism caused by multiple serotypes of botulinum neurotoxin (BoNT) is still a challenge due to the lack of a reliable detection method. The present study develops a feasible laboratorial method based on an isotope dilution Immuno-Endopep-MS to detect BoNTs and determine their serotypes and activities in clinical samples. Eleven positive foodborne botulism cases out of a total of 17 suspected cases in China, 2019–2022, were determined by the established method. Blood, urine, vomitus, gastric mucosa samples, and food samples were employed and evidenced to be suitable for the detection. Results showed that, although single type A-intoxication was still the first cause among these foodborne botulism cases, other causes involving type E, type B, and their mixed types were also determined, providing a glimpse to the serotype profile of botulism happened in recent years in China. Furthermore, in order to provide insights into in vivo profiles of toxin serotypes, a comprehensive analysis of clinical specimens collected from one family of four patients was performed during a clinically and therapeutically relevant time frame. Serotypes and concentrations of BoNT in specimens revealed a good correlation with symptoms and progresses of disease. Additionally, serum was proved to be more suitable for detection of BoNT/A with a detection window up to 12 days. A urine sample, although rarely reported for foodborne botulism diagnosis, was validated to be suitable for testing BoNTs, with a longer detection window up to 25 days. To the best of our knowledge, this is the first comprehensive analytical research on in vivo profiles of serotypes A, B, and E in different types of specimens from mixed botulism cases. Our method and findings facilitate the toxin detection and identification by clinical diagnostic laboratories.

Botulinum Toxin Type A: Adverse Events and Management

Aesthetic medicine is witnessing an increasing exploitation of all the procedures. The demand has never been higher than it is today. The number of practitioners is also increasing year by year. Consequently complications and other kinds of related troubles and procedures are also rising. Never like today is fundamental, in case of troubles, how to properly manage with the most frequent issues. In aesthetic medicine field, botulinum toxin procedures are the safest. Lot of patients are worried about botulinum toxin despite the available scientific literature. Rare short-term complications are observed. In the most of cases, nothing severe occurs if the international recommendations and the most recent guidelines are closely followed, the majority of them are injection related. This study is a review of rare or common problems that can occur and how to manage or solve the situations.

Aesthetic Treatments in Cancer Patients

Cancer patients are experiencing an increase in overall survival as a consequence of earlier diagnosis and newer effective anticancer therapies. However, cancer survivors often face long-term consequences from their original cancer diagnosis and long-term sequelae of anticancer treatment. Maintaining patients' quality of life is of paramount importance and this can be accomplished by a multidisciplinary treatment approach, including aesthetic treatments to improve patients' body image and positively impact their quality of life. In this perspective, we will discuss the importance of aesthetic treatments in cancer patients. In addition, we will summarise the data available regarding the use of several aesthetic treatments such as fillers, botulinum toxin and laser use in cancer patients, their safety, their efficacy, and the specific precautions that need to be implemented in this particular subset of cancer patients.