Evaluation of Collagen Dermal Filler with Lidocaine for the Correction of Nasolabial Folds: A Randomized, Double-Blind, Multicenter Clinical Trial.

Purpose: Porcine-based dermal injectable collagen is effective for nasolabial fold correction. In the present study, a new dermal injectable collagen, incorporating a novel cross-linking technology and premixed with lidocaine, was introduced. The study aimed to determine the efficacy of the new dermal injectable collagen in improving bilateral nasolabial fold wrinkles, and reducing pain during injection. Patients and Methods: This prospective, double-blind, multicenter, parallel-group, randomized trial enrolled participants with moderate-to-severe bilateral nasolabial fold wrinkles from February 2019 to March 2021. Participants were randomly assigned to the test group (new dermal injectable collagen with lidocaine featuring a novel cross-linking technology) or control group (traditionally cross-linked dermal injectable collagen with lidocaine). Participants were monitored for adverse events (AEs), and for pain using the Thermometer Pain Scale (TPS) and a visual analog scale (VAS). Efficacy was measured using the Wrinkle Severity Rating Scale (WSRS) and the Global Aesthetic Improvement Scale (GAIS). Results: On the poor or better sides, the 2 groups exhibited a significant decrease in WSRS scores at 4, 12, 24, and 36 weeks after treatment, compared to baseline WSRS scores (all, p < 0.05). Compared to the control group, the test group had a greater decrease in WSRS score (poor or better sides) at 12, 24, 36, and 52 weeks after treatment (all, p < 0.05). A similar observation was also found in the WSRS response rate and GAIS score of the 2 groups. VAS and TPS scores were not significantly different between the 2 groups (p > 0.05), indicating that pain reduction was similar in the 2 groups. All AEs were anticipated AEs associated with facial aesthetic injections, and most recovered within 0 to 30 days without sequelae. There were no differences in AEs between the 2 groups (all, p > 0.05). Conclusion: The new dermal injectable collagen with lidocaine exhibited better efficacy for correcting nasolabial fold wrinkles compared to the control group. Both relieved pain and produced only transient and tolerable AEs.

Stem Cell-Derived Extracellular Vesicle-Bearing Injectable Hydrogel for Collagen Generation in Dermis.

Despite the remarkable advances of dermal fillers that reduce wrinkles caused by dermis thickness reduction, they still lack effective hydrogel systems that stimulate collagen generation along with injection convenience. Here, we develop a stem cell-derived extracellular vesicle (EV)-bearing thermosensitive hydrogel (EVTS-Gel) for effective in vivo collagen generation. The TS-Gel undergoes sol-gel transition at 32.6 °C, as demonstrated by the storage and loss moduli crossover. Moreover, the TS-Gel and the EVTS-Gel have comparable rheological properties. Both hydrogels are injected in a sol state; hence, they require lower injection forces than conventional hydrogel-based dermal fillers. When locally administered to mouse skin, the TS-Gel extends the retention time of EVs by 2.23 times. Based on the nature of the controlled EV release, the EVTS-Gel significantly inhibits the dermis thickness reduction caused by aging compared to the bare EV treatment for 24 weeks. After a single treatment, the collagen layer thickness of the EVTS-Gel-treated dermis becomes 2.64-fold thicker than that of the bare EV-treated dermis. Notably, the collagen generation efficacy of the bare EV is poorer than that of the EVTS-Gel of a 10× lesser dose. Overall, the EVTS-Gel shows potential as an antiaging dermal filler for in vivo collagen generation.

Long-term duration and safety of Radiesse (+) for the treatment of jawline.

BACKGROUND: Calcium hydroxyapatite (CaHA)-carboxymethylcellulose (CMC)+ has unique properties that make it optimal for lifting, contouring, and defining the jawline. This long-term follow-up of a randomized, multicenter, rater-blinded trial reports efficacy and safety of CaHA-CMC(+) through 48 and up to 60 weeks post-treatment. METHODS: Eligible patients were randomized (2:1) to the treatment or the control/delayed treatment group to receive CaHA-CMC(+) injections in both jawlines. While touch-ups were permitted 4 weeks post-treatment for both groups, only the treatment group was eligible for optional retreatment after 48 weeks. The primary outcome was ≥1-point improvement on both jawlines on the Merz Jawline Assessment Scale (MJAS); secondary endpoints included the Subject Global Aesthetic Improvement Scale (SGAIS) among others. Post hoc analysis included pooling up to 48-week data from the combined treatment and control/delayed groups and 60-week data for the treatment group. RESULTS: Overall, 175 received treatment. MJAS responder rates were 77.9%, 78.7%, and 62.9% at 12, 24, and 48 weeks post-treatment, respectively. Responder rate on the MJAS at 60 weeks was 74.6% for those who received retreatment and 43.5% for those patients who received only the initial and touchup treatments. SGAIS scores demonstrated 93.4%, 85.6%, and 68.5% of patients rated themselves very much improved after 12, 24, and 48 weeks, respectively. Adverse events consisted of procedure or CaHA-CMC(+)-related events that were mostly resolved and overwhelmingly mild. CONCLUSIONS: CaHA-CMC(+) produced clinically meaningful and long-lasting improvements in jawline contour and was well tolerated in patients through 60 weeks. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03583359.

In Vitro Cytocompatibility Analysis and Comparison of Different Hyaluronic Acid Fillers for Minimally Invasive Esthetics.

BACKGROUND/AIM: To overcome the natural visual consequences of the physiological aging process, the use of biodegradable fillers made of hyaluronic acid or sodium carboxymethyl cellulose is increasingly popular in modern esthetic medicine. Clinicians can choose from a wide range of fillers with variable compositions and rheological properties, and therefore with different application areas and injection depths. The aim of this study was to analyze and compare the most commonly used fillers for facial augmentation regarding their in vitro biocompatibility and to find potential correlations to their rheological properties. MATERIALS AND METHODS: In the present study, direct and indirect in vitro cytotoxicity analysis according to DIN EN ISO 10993-5 were performed on 39 different filler materials for facial augmentation. RESULTS: All fillers analyzed in this study overall showed satisfactory results in the direct and indirect cytocompatibility tests. While no material was outside the threshold values in the 2,3-bis-(2-methoxy-4-nitro-5-sulphenyl)-(2H)-tetrazolium-5-carboxanilide (XTT) cell viability and bromodeoxyuridine (BrdU) cell proliferation assays or in the live-dead staining, only 7 out of the 39 fillers reached the required values in the lactate dehydrogenase assay. CONCLUSION: All biodegradable fillers examined in this study were found to be sufficiently cytocompatible. Although the qualitative analysis of the test results showed differences between the fillers, no concrete correlation between test performance and composition or manufacturer of the fillers was found. Future efforts are required to provide clinicians with even better support in choosing the right filler for optimal outcome and patient satisfaction.

Fibrotic reaction to hyaluronic acid fillers in the face.

BACKGROUND: Hyaluronic acids (HAs) can have very different actions not only depending on injector and host factors but also depending on their molecular weight. Whereas short chain HA has immunological activity long chain HA influences fibroblasts and may stimulate them to produce collagen. Although this is generally thought to be a positive feature it may be disadvantageous in certain localizations. PATIENTS AND METHODS: We have encountered 23 patients who developed fibrous tissue next to the nasolabial folds accentuating them and becoming very obvious while smiling. Hyaluronidase injection did not reduce this mass. RESULTS: Intralesional triamcinolone acetonide injection led to rapid improvement. DISCUSSION: Fibrotic tissue reaction not responding to hyaluronidase may be the result of HA injection and can effectively be treated with intralesional steroid injection.

A narrative-style review of non-surgical rhinoplasty: Indications, outcomes, and limitations.

The aim of this narrative-style review was to evaluate non-surgical rhinoplasty in terms of indications, outcomes, and limitations. Both 'PubMed' and 'Science Direct' were reviewed by all authors, in order to reach consensus with regard to the chosen studies. Studies published from 1980 to 2023 were searched using the key terms "non-surgical rhinoplasty", "dermal filler", "thread lifting", and "botulinum toxin", and relevant papers were selected. Non-surgical rhinoplasty refers to the use of injectable temporary fillers to augment selected areas of the nose, in order to achieve improved appearance or function in select patients. It includes the use of dermal fillers, thread lifting, and botulinum toxin injections. The perfect dermal filler would be inexpensive, safe, painless to inject, hypoallergenic, and long lasting. In addition, it should produce consistent and predictable results, feel natural under the skin, take little time to inject, be ready to use, exert no downtime on the patient, and have a low risk of complications. Regions of the nose treated with filler injections include the frontonasal angle, dorsum, nasolabial angle, and columella. Thread lifting and botulinum toxin injection are the other methods of non-surgical rhinoplasty. Dermal fillers, thread lifting, and botulinum toxin injections can be used as non-surgical rhinoplasty. Dermal fillers and botulinum neurotoxin can be used alongside each other to allow minimally invasive resculpting of the nasal region and midface, compensating for a reduction in tissue volume and the formation of rhytides.

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 following 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. Additionally, 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.

Objective Noninvasive Measurement of the Volumizing Effect of a Dermal Filler: An In Vivo Study.

BACKGROUND: Information about the volumizing effects of dermal fillers is critical for physicians' understanding of product features and prudent decision-making in clinical practice. It is important for material engineers to develop and optimize new dermal fillers, especially when comparing the physiochemical properties of a new product with those of existing fillers that are used worldwide. OBJECTIVE: This study aimed to establish a reliable, noninvasive method for in vivo quantitative evaluation of the filling effect in order to predict possible effectiveness after filler injection and to evaluate the degradation trend over time. METHODS: A rabbit model of ear injection with dermal fillers was established. Hyaluronic acid (HA) filler was injected into the subcutaneous layer of rabbit ears, resulting in a stable skin bulge. Ultrasonography was used to noninvasively measure the skin bulge for volume calculation; the volume change was analyzed periodically until 38 weeks. Pathological examination, the gold standard, was performed to confirm degradation. RESULTS: The immediate volumizing effect of HA filler injection was macroscopically observed as a local skin bulge. Ultrasound was able to precisely detect the shape of the filler and calculate the length, width, and height of the skin bulge at each time point. The degree of uplift and amount of residual samples in the pathological evaluation were consistent with the results of morphological observation using ultrasound. CONCLUSION: Evaluation of the volume impact of dermal filler through the rabbit ear injection model evaluation enables material science evaluation in the early stage of material development, and has certain clinical reference value. LEVEL OF EVIDENCE I: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Profiloplasty and facial contouring with injectables: A holistic, practical, and user-friendly approach.

BACKGROUND: Expansion of the aesthetic treatment armamentarium with novel injectable products has greatly improved our ability to reshape and enhance the facial profile. However, full-face "profiloplasty" with injectables remain a nascent concept and is insufficiently considered in daily practice. While techniques have been widely published for treating the individual facial areas that constitute an attractive profile-including the forehead, nose, lips, jawline, and chin-the literature remains fragmented on more universal methods for profile improvement. AIMS: To collate disparate knowledge on profile optimization with injectables, and define a holistic, practical, and user-friendly approach to profiloplasty and facial contouring. METHODS: Consideration is given to key anatomical aspects and the changes that occur with age; patient assessment parameters for planning profiloplasty; and the technical specifications, product selection, and essential safety considerations for minimizing the risk of complications and optimizing the effectiveness of treatment. RESULTS: Relevant case studies are presented. CONCLUSIONS: Holistic approaches of this type are essential if we are to maximize the potential of full-face treatment with injectables-both now and in the future.

Microinjection Technique: A Novel and Comprehensive Approach for Nose Reshaping with Hyaluronic Acid Fillers.

Introduction: Nose reshaping with hyaluronic acid (HA) fillers, also known as medical rhinoplasty, is an increasingly popular, minimally invasive aesthetic procedure. As the demand for nasal reshaping continues to rise, it is essential to develop safe and efficient injection techniques and assess satisfaction to ensure optimal outcomes and patient-centered care. Objective: This study aims to evaluate patient and physician satisfaction with hyaluronic acid filler applications using microinjection technique for nasal reshaping. Methods: The study included healthy adult patients who underwent medical rhinoplasty with the same HA filler using the microinjection technique. Patient satisfaction levels were evaluated at one and six months after the last injection using the Global Patient Satisfaction Scale (GPSS). Additionally, an independent dermatologist conducted a clinical evaluation for each patient by comparing before and after clinical pictures, using the Aesthetic Improvement Scale (AIS). Any side effects were recorded during each session and follow-up period for six months. Results: A total of 40 patients (37 women and 3 men) participated in the study. The most frequently targeted anatomical areas for filler injections were the nasal tip (100%), columella (100%), nasal prominence (100%), nasal dorsum (85%), and nasal root (82.5%). Injections distal to the nasolabial fold (NFL) were performed in 2.5 percent of patients. Patients expressed high satisfaction with the results at both one and six months after the procedure (mean GPSS, respectively; 4.65 and 4.47). Similarly, clinicians reported satisfaction with outcomes at the same time points (mean AIS, respectively; 1.7 and 1.4). Apart from mild pain during the procedure and transient erythema afterward, no side effects were recorded. Conclusion: Medical rhinoplasty with HA fillers using the microinjection technique is an effective and reliable procedure. This technique provides safe and aesthetically pleasing results from both patient and dermatologist perspectives, making it a favorable option for nasal reshaping with HA dermal fillers.

Complications after breast augmentation with dermal fillers containing copolyamide: A systematic review.

Background: Dermal fillers containing copolyamide are used for breast augmentation and are marketed under different labels, such as Aquafilling, Los Deline, Aqualift, and Activegel. In recent years, the number of publications reporting complications after use of these fillers has increased. Methods: Through a computerized search following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, a systematic review of published studies on complications, treatment options, and radiological findings related to breast augmentation with dermal fillers containing copolyamide was performed. Publications between January 1, 2007, and January 23, 2023, were included. Retrieved studies were screened for inclusion and quality assessment. The Joanna Briggs checklist for case reports and the Strengthening the Reporting of Observational Studies in Epidemiology checklist for cross-sectional studies were used. Results: Sixteen studies met the inclusion criteria: 14 case reports and 2 retrospective cohort studies, including 196 women and 333 complications. Long-term complications (≥30 days after surgery) were described in 15 studies. The most commonly reported complications were nodules in the breast (130 patients), pain (92 patients), inflammation and/or infection (43 patients), breast deformities (35 patients), and migration of the filler to the pectoralis muscle, abdominal wall, thoracic wall, pubic area, back, or upper extremity (27 patients). The median time between injection of the dermal filler and any complication was 18 months, and the majority of patients with complications required surgical intervention. Conclusion: Given the reports of severe complications months to years after injection of dermal fillers containing copolyamide and the lack of studies evaluating long-term safety, our interpretation is that dermal fillers containing copolyamide should not be used for breast augmentation.

Complications of Injectables.

The field of non-surgical esthetic procedures has witnessed a significant surge in demand in recent years, with neuromodulators, skin treatments, and dermal fillers contributing significantly to the industry's growth. These procedures have become increasingly popular, reflecting the broader acceptance of esthetic enhancements in society. Neuromodulators play a pivotal role in facial rejuvenation, but they require precise knowledge of facial anatomy to optimize results and prevent complications. They include rare hypersensitivity reactions, local injection reactions, and brow and eyelid ptosis. Dermal fillers, both non-permanent and permanent, are widely used to restore volume and improve facial contours. However, they also carry risks, including bruising, temporary edema, and lumps. Permanent fillers present higher complication rates, and their use should be approached with caution. Vascular occlusion is a rare but severe complication associated with dermal fillers. To mitigate these risks, practitioners must have a comprehensive understanding of their compositions and potential complications. Overall, while non-surgical esthetic procedures offer remarkable results with minimal downtime, the importance of training, anatomic knowledge, and effective complication management cannot be overstated in ensuring patient safety and satisfaction in this evolving field of medicine.

The Use of Facial Fillers in Clinical Practice: The Level of Patient Satisfaction and an Overview of Common Clinical Complications. / [Artículo traducido] Uso de rellenos faciales en la práctica clínica: nivel de satisfacción del paciente y visión general de las complicaciones clínicas comunes.

BACKGROUND: Patient esthetic satisfaction following facial fillers is an essential topic that should be studied as the number of individuals seeking treatment increases. The face is an essential component of the human body that is frequently associated with beauty, youthfulness, and health. Individuals may seek facial augmentation with fillers for a variety of reasons, such as congenital, acquired by means of aging or disease, or current aesthetic trends. OBJECTIVE: The aim is to assess patient's aesthetic satisfaction and description of common clinical complications in relation to the facial filler injections. METHOD: A cross sectional survey using a questionnaire derived from the global aesthetic improvement scale and WHO quality of life scale, convenience sampling was used to recruit patients attending cosmetic clinics, descriptive analysis and Chi-square methods were used to analyze the data. RESULTS: In the study, 500 female participants, with an average age of 28.48 years, were included. Over 90% reported improvement after filler treatment, ranging from improved to very much improved. A statistically significant correlation was observed between patient satisfaction and the number of filler treatments and the anatomical injection site. However, no statistically significant correlation was found when considering age groups. Local side effects, such as swelling and redness at the injection site, were common but generally mild and of short duration. CONCLUSION: Although the satisfaction level is currently high, practitioners in the field need to pay more attention to this important outcome, since understanding the patient's motivation and expectation before proceeding with the procedure is very important and can contribute significantly in determining patient satisfaction with the result.

Causes and management of sight threatening complications of dermal filler injections: A review.

Injectable dermal fillers continue to increase in popularity in aesthetic medicine. Although rare, vision loss secondary to filler injections is a devastating complication associated with a poor visual prognosis. The mechanism for vision loss is thought to be related to retrograde embolization of the dermal filler from peripheral vessels in the face into the ophthalmic arterial system. Early recognition and prompt management are essential if vision is to be salvaged. The use of retrobulbar hyaluronidase is still contentious, however when administered by a specialist, this treatment gives the best chance at visual recovery and should be considered for all cases.

Multifocal strokes and vision loss from PDLLA filler injections.

BACKGROUND: Poly-D, L-lactic acid (PDLLA) is increasingly used as a commercial dermal filler due to its lasting cosmetic properties. Consequently, PDLLA-related vascular complications are increasingly recognized and described. Herein, we describe the first known occurrence of multifocal strokes from the use of PDLLA as a cosmetic dermal filler, and discuss the mechanisms facilitating PDLLA's entry into the intracranial arterial system. CASE PRESENTATION: A middle-aged female presented with acute vision loss of both eyes immediately after dermal injections of PDLLA to her nasolabial folds and infraorbital regions. There were no additional neurological deficits. Dilated fundal examination revealed retinal edema bilaterally, with deposition of filler material in the retinal arteries. Magnetic resonance imaging of her brain and orbits demonstrated multifocal strokes (left caudate head, right medial frontal lobe) and ischemia of the left optic nerve. The temporal proximity of the dermal injections to her symptoms, guided by fundal examination and neuroimaging findings, allowed us to attribute her strokes and ischemic optic neuropathy to PDLLA's entry into, and embolism within, the intracranial arterial system. She was treated with hyperbaric oxygen therapy and experience improvement to her right eye's vision, although poor vision persisted in her left eye. CONCLUSION: While PDLLA is generally considered safe, its increasing use as a cosmetic filler renders it crucial for physicians to be cognizant of its vascular complications, especially when early recognition and treatment are essential in mitigating their devastating ramifications.

Implications for cumulative and prolonged clinical improvement induced by cross-linked hyaluronic acid: An in vivo biochemical/microscopic study in humans.

In photoaged human skin, type I collagen fragmentation impairs dermal extracellular matrix (ECM) integrity, resulting in collapsed/contracted fibroblasts with reduced type I procollagen synthesis. Injections of cross-linked hyaluronic acid (CL-HA) reverse these deleterious changes. To investigate the time course and effects of biochemical changes induced by injected CL-HA, particularly whether fibroblast activation leads to accumulation/deposition of dermal collagen, we injected CL-HA into photoaged skin of human participants over 60 years-old and performed biochemical/microscopic analyses of skin samples. Beginning 1 week post-injection and lasting 6-9 months, fibroblasts exhibited activation, including increased immunostaining and gene expression of markers of type I collagen synthesis, such as heat shock protein 47 and components of the transforming growth factor-ß pathway. At 1 week post-injection, multiphoton microscopy revealed elongation/stretching of fibroblasts, indicating enhanced dermal mechanical support. At 4 weeks, second-harmonic generation microscopy revealed thick collagen bundles densely packed around pools of injected CL-HA. At 12 months, accumulation of thick collagen bundles was observed and injected CL-HA remained present in substantial amounts. Thus, by occupying space in the dermal ECM, injected CL-HA rapidly and durably enhances mechanical support, stimulating fibroblast elongation and activation, which results in thick, densely packed type I collagen bundles accumulating as early as 4 weeks post-injection and continuing for at least a year. These observations indicate that early and prolonged clinical improvement following CL-HA injection results from space-filling and collagen deposition. As type I collagen has an estimated half-life of 15 years, our data provide the foundations for optimizing the timing/frequency of repeat CL-HA injections.

Morphea-like discoid lupus erythematosus in a patient with a history of polyacrylamide gel injection: A case report.

BACKGROUND: Discoid lupus erythematosus (DLE) is an autoimmune disease with multifactor etiology which develops in genetically susceptible patients. Rarely, DLE lesions can mimic other connective tissue disorders such as morphea. The growing application of soft tissue fillers is associated with increasing complications. Some substances used for soft tissue augmentation such as silicon implants may trigger lupus erythematosus diseases. CASE REPORT: Here we report a case of morphea-like discoid lupus erythematosus developed several years after polyacrylamide dermal filler (PAAG) injection for facial rejuvenation. CONCLUSION: As noninvasive procedures like dermal filler injections are increasing worldwide, physicians may consider the long-term probable side effects of these compounds.

Biostimulating fillers and induction of inflammatory pathways: A preclinical investigation of macrophage response to calcium hydroxylapatite and poly-L lactic acid.

INTRODUCTION: Initial macrophage response to biostimulatory substances is key in determining the subsequent behavior of fibroblasts and the organization of newly synthesized collagen. Though histological studies suggest that calcium hydroxylapatite (CaHA) filler initiates a regenerative healing response with collagen and elastin deposition similar to natural, healthy tissue rather than an inflammatory response with fibrosis, the relative activity of macrophages stimulated by CaHA, as well as how this activity compares to that induced by other biostimulatory fillers, has not been explored. The aim of the study is to characterize the in vitro macrophage response to two biostimulory fillers, CaHA and PLLA (poly-L lactic acid), and to evaluate their inflammatory potential. METHODS: Primary human macrophages were incubated with two dilutions (1:50 and 1:100) of commercially available CaHA or PLLA. After 24 h incubation, an inflammation array was used to screen for the expression of 40 cytokines, released by macrophages. ELISA was used to confirm array results. RESULTS: Four cytokines were significantly upregulated in M1 macrophages incubated with PLLA compared to both unstimulated controls and CaHA: CCL1 (p < 0.001), TNFRII (p < 0.01), MIP-1α (p < 0.05), and IL-8 (p < 0.001). In M2 macrophages, MIP-1α (p < 0.01) and MIP-1ß (p < 0.01) were significantly upregulated by PLLA compared to CaHA and unstimulated controls. CONCLUSION: Together, these findings indicate that the CaHA mode of action is a non-inflammatory response while PLLA initiates expression of several cytokines known to play a role in inflammation. Our study supports the concept that these two "biostimulatory" fillers follow distinct pathways and should be considered individually with regard to mechanism of action.

Allergic Complications of Hyaluronidase Injection: Risk Factors, Treatment Strategies, and Recommendations for Management.

BACKGROUND: Hyaluronidase is used as a reversal agent for hyaluronic acid fillers and to increase the diffusion of other medications after infiltration. Cases of hyaluronidase allergy have been described in the literature since 1984. However, it is still frequently misdiagnosed. This review aims to summarize the current literature to describe the clinical picture of hyaluronidase allergy and identify any risk factors associated with its development, as well as provide recommendations for management in plastic surgery. METHODS: A digital search of PubMed, Scopus, and Embase databases was performed by two reviewers following the PRISMA guidelines. This search identified 247 articles. RESULTS: Two hundred forty-seven articles were identified, and 37 of them met the eligibility criteria. One hundred six patients with a mean age of 54.2 years were included in these studies. History of allergy to other substances (timothy grass, egg white, horse serum, penicillin, insect bites, wasp venom, thimerosal, potassium, histamine, phenylmercuric acetate, and nickel) and allergic diseases (asthma, dermatitis, atopy, rhinitis) was reported. A large portion of the patients with a history of repeated exposure (2-4) experienced the symptoms with their second injection. Nonetheless, there was no significant association between time to allergy development and the number of exposures (P = 0.3). Treatment with steroids +/- antihistamines resulted in the rapid and predominantly complete reversal of the symptoms. CONCLUSIONS: Prior injections or sensitization by insect/wasp venom might be the primary factor associated with hyaluronidase allergy development. The time between the repeated injections is not a likely contributor to the presentation. LEVEL OF EVIDENCE III: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .