|Year : 2020 | Volume
| Issue : 1 | Page : 22-27
Comparative study of three different modalities of topical anesthesia in various dermatological procedures
Jyoti Gupta1, Niti Khunger2, V Ramesh3
1 Jyoti Gupta Clinic, New Delhi, India
2 Department of Dermatology and STD and Apex Regional STD Centre, Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi, India
3 Department of Dermatology and Venereology, VMMC and Safdarjung Hospital, New Delhi, India
|Date of Submission||27-Dec-2018|
|Date of Decision||30-Sep-2019|
|Date of Acceptance||18-Feb-2020|
|Date of Web Publication||23-Jun-2020|
Dr. Jyoti Gupta
Jyoti Gupta Clinic, B-2, Panchsheel Enclave, New Delhi - 110 017
Source of Support: None, Conflict of Interest: None
Background: Infiltrative anesthetics are frequently chosen because of their proven safety record, low cost, ease of storage, widespread availability, and rapid onset of action; a good topical anesthetic agent can eliminate the use of painful injections prior to procedures. Aims: The present study was carried out to compare the eutectic mixture of local anesthetic (EMLA), cryogel, lignocaine spray, and controls for pain caused during common dermatological procedures. Methods: This study included 120 patients who were divided into four groups with 30 patients each for needle extraction for molluscum contagiosum and milia; intralesional injection for keloids and alopecia areata; radiofrequency ablation for warts, acrochordons, and intradermal nevus; and dermabrasion for surgical treatment of vitiligo. Topical anesthetics such as EMLA, cryogel, and lignocaine spray were applied and pain was assessed using visual analog scale (VAS) score. Data were analyzed using Microsoft Excel. P <0.05 was considered statistically significant. Results: The mean VAS score was highest for the control group (VAS = 5.2) and lowest for EMLA group (VAS = 1.3). There was a significant reduction in the pain with the topical anesthetic application as compared to controls. The mean VAS score for all procedures showed a significant pain reduction with topical anesthetic application as compared to controls (P < 0.05). Limitations: Lack of standardized methods of topical anesthetic application and there is the inherent limitation in the exactness of pain scoring scale available for use. Conclusion: All modalities of topical anesthesia had proven their efficacy for dermatological procedures, but in a procedure like dermabrasion, it may not be possible to use any of the topical anesthetics solely to produce sufficient anesthesia.
Keywords: Anesthetic, lignocaine, topical
|How to cite this article:|
Gupta J, Khunger N, Ramesh V. Comparative study of three different modalities of topical anesthesia in various dermatological procedures. Indian J Drugs Dermatol 2020;6:22-7
|How to cite this URL:|
Gupta J, Khunger N, Ramesh V. Comparative study of three different modalities of topical anesthesia in various dermatological procedures. Indian J Drugs Dermatol [serial online] 2020 [cited 2020 Aug 9];6:22-7. Available from: http://www.ijdd.in/text.asp?2020/6/1/22/287432
| Introduction|| |
Fear of the needle is a real issue with many patients. It is invasive and sometimes an obstacle for inducing anesthesia for minor surgical procedures. Although infiltrative anesthetics are frequently chosen because of their proven safety record, low cost, ease of storage, widespread availability, and rapid onset of action, a good topical anesthetic agent can eliminate the use of painful lidocaine injections prior to procedures. In addition, topical anesthesia reduces the risk of HIV and other infections transmission to the physicians, health-care workers, and patients.
Most of the procedures in dermatology are done either with no anesthesia or infiltrative anesthesia with lignocaine. With the increasing dermatological procedures, the need for effective topical anesthesia continues to grow.
There are many different topical anesthetics available for pain control. These include cryoanesthesia, cocaine, benzocaine, lidocaine and its various preparation, prilocaine, tetracaine, betacaine, iontophoresis, etc., Topical anesthetics control pain perception and hence alter the pain reaction of an individual.
Out of the topical anesthetics, a widely used agent over the past decade, a eutectic mixture of local anesthetics (EMLAs) cream, is a 5% eutectic mixture composed of 2.5 mg/mL of lidocaine and 2.5 mg/mL of prilocaine in an oil-in-water emulsion cream.
Numerous lidocaine-containing products are available, but comprehensive reviews are lacking regarding their relative safety profiles and appropriate dermatologic uses. There have been very few studies on the efficacy comparisons of various topical anesthetics in routinely performed dermatological procedures. The aim of this study was to make a comparative evaluation of the three modes of topical anesthesia such as EMLA, cryogel, and lignocaine spray versus controls in various common dermatological procedures performed in the outpatient department.
A hospital-based cross-sectional study was carried out on 120 patients in the Department of Dermatology and STD, Safdarjung Hospital, over 1½ years based on the defined criteria.
- Patients of age >12 years
- The patient requiring the following procedures:
- Needle extraction for molluscum contagiosum and milia
- Radiofrequency ablation for warts, acrochordons, and intradermal nevus
- Intralesional injection for keloids and alopecia areata
- Dermabrasion for surgical treatment of vitiligo.
At least four evaluable lesions on comparable sites.
- Patients not able to interpret pain sensation
- Patients with lesions on the mucosa or with broken skin
- Patients with hypersensitivity to lidocaine or prilocaine or other ester or amide anesthetics
- Patients with lesion with underlying hypoesthesia.
This study included 120 patients which were divided into four groups with 30 patients each for needle extraction, intralesional injection, radiofrequency ablation, and dermabrasion. An attempt was made to compare EMLA, cryogel, lignocaine spray, and controls for pain caused during the above-mentioned dermatological procedures.
The patient was informed for the extent of the study and consent form was signed by each patient.
The individual patient lesions were treated with:
- EMLA cream (Curatio Healthcare Pvt. Ltd., Chennai)
- Cryogel pack
- Lignocaine spray 15% (ICPA Health Products Ltd., Mumbai)
- One lesion served as control.
EMLA cream was placed on one lesion. A thick layer of EMLA (1 gm/10 cm2) was occluded for a time period of at least 60 min. Occlusion over EMLA was removed and cleaned with normal saline, and under aseptic conditions, the procedure was performed according to the respective condition using a standardized technique.
Another lesion from comparable site (either another site on same limb/area or similar lesion on contralateral limb/side of the body) was selected, lignocaine spray kept over a distance of 10 cm was sprayed 3 times (equivalent to 45 mg of lignocaine) over lesion for at least 30 min, and the procedure was repeated.
After that, cryogel kept in sterilized gloves was placed on another lesion for 5 min and the procedure was repeated.
Another lesion was selected as a control site and the procedure was repeated.
Each time after the procedure, the visual analog scale (VAS) was used to determine pain. A scale ranging from 0 to 10 was shown to the patient and answer of the patient recorded, 0 being no pain and 10 being the worst pain possible. The patient was monitored for any adverse effects.
The mean VAS score between four groups was compared using ANOVA test.
A comparison of mean VAS score of each topical anesthetic for different sites of application was compared using Student's t-test. P <0.05 was taken as criteria for the level of significance.
Microsoft Excel was used to analyze the data.
| Results|| |
The study was conducted on 120 patients. Most of the patients belonged to the age group of 20–39 years [Figure 1]. The mean age of the study patients was 28.8 years. The age distribution for individual procedure is shown in [Table 1].
There was almost an equal sex distribution [Table 2]. However, the sex distribution for individual procedures showed different trends, as depicted in [Table 3].
|Table 3: Sex distribution for individual dermatological procedures (number)|
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In the present study, 8 different diagnostic groups of patients were included. Patients with vitiligo were maximum (n = 30) and intradermal nevus were minimum (n = 4) [Figure 2].
Most of the patients had lesions on the face followed by the lower limb, upper limb, neck, trunk, and finally, scalp [Table 4].
The mean application time differed for various treatments as decided in the protocol of the study [Table 5].
The mean VAS score was highest for the control group (VAS = 5.2) and lowest for the EMLA group (VAS = 1.3). There was a significant reduction in the pain with the topical anesthetic application as compared to controls [Figure 3].
|Figure 3: Comparison of mean VAS score of different topical anesthetics (ANOVA test). * P < 0.05: Statistical significant difference of topical anesthetics (inter-group) when compared to controls.|
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The mean VAS scores varied among different lesion sites for different anesthetics (P< 0.05, ANOVA test). In the EMLA, lignocaine, and cryogel group, the mean VAS score for the face and neck was significantly lower than for other sites. In the control group, the mean VAS score for the face was significantly lower than for other sites [Table 6].
|Table 6: Mean visual analog scale score comparison among different lesion sites|
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The mean VAS score for all procedures showed a significant pain reduction with a topical anesthetic application as compared to controls. In the needle extraction procedure, EMLA and lignocaine spray were both superior to cryogel; however, there was no significant statistical difference between EMLA and lignocaine spray (P = 0.07). In the RFA procedure, EMLA was superior to both cryogel and lignocaine spray and lignocaine spray was superior to cryogel.
In the dermabrasion procedure, EMLA was superior to both cryogel and lignocaine spray; however, there was no significant statistical difference between cryogel and lignocaine spray (P = 0.89) [Table 7].
|Table 7: Mean visual analog scale score comparison in different procedural groups|
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Side effects of topical anesthetics
Of 120 total patients, 5 (4%) patients had blanching and 4 (3.5%) had edema and redness at the site of application of EMLA which subsided on its own in 3–4 h without causing any discomfort to the patient. Five (4%) patients felt discomfort due to the coldness of cryogel, and therefore, cryogel application was discontinued before 5 min in these patients. Four (3.5%) patients felt irritation on the application of lignocaine spray which subsided in the next 5 min of application.
| Discussion|| |
We found that all modalities of topical anesthetics used are a practical and safe alternative to injections in pain control for dermatological procedures. In our study, the mean age of the patients was 28.8 years. Children <12 years were not included due to difficulty in interpreting the pain sensation via VAS score by them.
There was almost an equal sex distribution overall. However, there was a predilection for females in procedures like needle extraction and dermabrasion and predilection for males for intralesional injection and radiofrequency ablation.
Time of application of EMLA varied from 60 to 70 min, with a mean time being 60.9 min.
Literature suggests a minimum of 60 min for the effect of EMLA to become evident.,,, However, Hopkins et al. showed no variation in analgesia for application times between 30 and 300 min.
The time of application of cryogel varied from 4 to 6 min, with mean time being 5 min. Yoon et al. used 1 min for effective analgesia for an antibiotic skin test. Kuwahara and Skinner used ice for 1–2 min to test for cutaneous analgesia. Sarifakioglu and Sarifakioglu applied ice for 5 min for botulinum toxin injection.
In our study, the time of application of lignocaine spray varied from 30 to 45 min, with a mean time being 31 min. A study by Kanai et al. had used 40% lignocaine spray for cutaneous analgesia with an application time of 30 min.
We found that all modalities of topical anesthesia were significantly better than controls, as a significant reduction in VAS scores was seen. Studies were done previously corroborate with our results.,,,
We found that EMLA was superior to cryogel and lignocaine spray. Lignocaine spray was found to be better than cryogel. Kuwahara and Skinner found out similar results of EMLA being superior to ice. Svensson et al. showed that EMLA application was better than 2% lignocaine gel in human oral mucosa. Sakamoto et al. found no significant difference between 10% lignocaine and EMLA. Hernández et al. concluded that EMLA was significantly better than 40% lignocaine ointment for pain induced due to laser.
When compared for individual procedures, all topical anesthesia were found superior to controls. One study by de Waard-van der Spek et al. on molluscum contagiosum showed that the application of EMLA cream is satisfactory for inducing analgesia for the curettage of molluscum contagiosum. Hallén et al. showed that analgesia by EMLA cream under occlusion for 20–105 min was sufficient in 96% men and in 40% women of genital warts.
A study by Bjerring and Arendt-Nielsen concluded that the maximal depth of analgesia (approx. 5 mm) by EMLA was observed 30 min after a 90-min application and during the 60-min period after a 120-min application of EMLA cream, for both sensory and pain thresholds. In the procedure like dermabrasion where adequate analgesia could not be achieved, the analgesic efficacy may be further improved by optimizing the application time of EMLA cream.
On comparing individual anesthetic agent according to the site of application, all anesthetics showed a better efficacy when used on the face and neck as compared to other regions of the body. A study by Holmes concluded that EMLA is effective on the face and thighs after as little as 25 min. The high efficacy of anesthetics on the face and neck can be due to relatively thin skin as compared to other body parts.
In EMLA group, 4% showed blanching and 3.5% showed edema and redness. However, these adverse effects with EMLA were transient and did not cause any clinically significant discomfort to patients. There was no evidence of pruritus, burning, purpura, contact hypersensitivity, methemoglobinemia, and any corneal injury.
Bjerring et al. found that EMLA cream produced a biphasic vascular response with an initial vasoconstriction, maximal after 1.5 h of application. After prolonged application (>3 h), vasodilatation occurred, presumably because of a smooth muscle relaxant effect of the analgesics. This late vasodilatation was unique to EMLA cream. However, in our study, edema and redness was seen with an application time of 60–70 min only.
Four percent patients of cryogel felt discomfort due to coldness of cryogel, and therefore, cryogel application was discontinued before 5 min in these patients. This discomfort was transient and clinically insignificant. However, it decreased the application time period of cryogel. In a study by Richman et al. where an ice pack was placed over one arm for 10 min, followed by insertion of an 18-gauge catheter, it was found that the mean pain score on arm pretreated with ice was significantly lower for the mean pain score for the control arm. However, most patients (61%) preferred no pretreatment with ice due to discomfort. Therefore, discomfort may be a limiting factor in the use of cryogel; 4 (3.5%) patients felt local irritation with lignocaine spray which subsided in the next 5 min of application. A study by Kanai et al. on 31 patients reported mild side effects in 3 patients consisting of local irritation (in 3 patients) and local flare (in 1 patient). All adverse events disappeared without medication within a few hours.
In this study, we have set out to assess the practical and safe use of topical anesthetics in pain control for dermatological procedures. All modalities of anesthesia had proven their efficacy for dermatological procedures, but in a procedure like dermabrasion, it may not be possible to use any of the topical anesthetics solely to produce sufficient anesthesia and it may not be possible to completely do away with the need for local injection. However, for procedures like needle extraction, intralesional injection, and radiofrequency ablation, these anesthetics can be used alone to provide sufficient analgesia. The amount of anesthetic and duration of application are not being standardized for various procedures in previous literature. Further studies are required to standardize the amount and duration of application.
Although EMLA cream had shown to be more effective than cryogel and lignocaine spray for most of the procedures, it has to be used under an occlusive dressing for at least 1 h and this has been the greatest drawback of this mode of anesthesia. In some patients, it was misplaced or rubbed off and had to be applied again.
Lignocaine spray had shown to be an effective anesthetic with minimal side effects. Moreover, it needs no occlusion, cannot be rubbed off, easily applicable, and needs less duration of application as compared to EMLA.
Cryogel had shown to be an effective anesthetic with minimal side effects, but it is inferior in efficacy to EMLA and lignocaine spray in some procedures. However, it is cheaper (almost no cost), easily accessible under any clinical scenario, and more importantly, safer, as there is no risk of a potential toxicity. Moreover, the duration of ice application (5 min) was determined from observations that longer ice application caused significant discomfort, while shorter application did not allow significant analgesia. However, in this study, few patients reported discomfort, but it was clinically insignificant. A more exact ice toleration threshold time would probably be ideal for which a randomized study would be required. The advantage of cryogel over ordinary ice was that it does not create any watery mess. It is reusable, convenient, and economical for repeated freezing.
Larger studies incorporating standardized testing methods would be ideal to prove the efficacy of this technique. Finally, there is the inherent limitation in the exactness of pain scoring scale available for use.
All modalities of topical anesthesia had proven their efficacy for dermatological procedures, but in a procedure like dermabrasion, it may not be possible to use any of the topical anesthetics solely to produce sufficient anesthesia. Although, EMLA had proven to be more efficacious than cryogel and lignocaine spray in some of the procedure, a sufficient amount of analgesia can be provided with both cryogel and lignocaine spray. There were very few side effects noticed like blanching, redness and edema with EMLA, discomfort with cryogel, and irritation with lignocaine spray. These effects subsided on its own and did not cause any significant problem to any patient.
The authors would like to thank Dr. Ketan Garg for assistance in medical writing and editing.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]