Introduction: Transepidermal drug delivery, using “laser-assisted drug delivery'', or microneedling, are new treatment modalities, that can improve drug penetration into skin in treatment of alopecia areata patients.
Objective: To evaluate the use of fractional carbon dioxide laser versus microneedling in transepidermal delivery of triamcinolone acetonide and platelet rich plasma in alopecia areata treatment.
Methods: Interventional comparative study carried out on 60 patients, randomly divided into four equal groups. Group I :Fractional Carbon dioxide laser and triamcinolone acetonide. Group II: Microneedling with Dermapen and triamcinolone acetonide. Group III: Fractional Carbon dioxide laser and Platelet-rich plasma. Group IV: Microneedling with Dermapen and Platelet-rich plasma. Patients were assessed clinically, using Severity of Alopecia Tool score and hair regrowth scale, and dermoscopically.
Results: In all treatment groups, there was improvement in the Regrowth scale, with statistical significance between the different groups at fourth (p= 0.001*) and last (p= 0.008*) visits, with highest, most significant changes in Pen-Steroid group. Comparing Regrowth scale at last visit, results were in favor of dermapen, compared to Carbon dioxide laser for Transepidermal drug delivery (p=0.023*); and in favor of triamcinolone acetonide, compared to Platelet-rich plasma as topical medication (p=0.015*). Dermoscopic signs of improvement included decrease in black dots, and appearance of Upright regrowing hairs (p= <0.001*).
Conclusion: Microneedling and fractional Carbon dioxide laser can be effectively used for transepidermal drug delivery for Alopecia areata treatment. Microneedling for delivery of Triamcinolone acetonide showed best treatment outcomes. Dermoscopy can be used in alopecia areata for evaluation of treatment response.
Trans-epidermal drug delivery (TED) depends on using ablative method (CO 2 laser, erbium lasers or ablative radiofrequency), to create vertical channels through the epidermis. This is followed by applying a medication (eg triamcinolone actenoide, platelet rich plasma) that is delivered through these channels into the skin. “Laser-assisted drug delivery” is the specific use of lasers for TED. Micro-needling technique can be used for the same purpose [ 1 ] .
The aim of this study is to evaluate the use of fractional carbon dioxide laser versus micro-needling in trans-epidermal delivery of triamcinolone acetonide and platelet rich plasma in alopecia areata (AA) treatment, clinically and dermoscopically.
This interventional comparative study was carried out on 60 patients, of either sex, presenting with AA to the Dermatology, Venereology and Andrology outpatient and Hair clinics in the Main University Hospital. The local Ethics Committee approved the study, and all procedures were in accordance with the Helsinki Declaration of 1975, as revised in 2000. All patients signed an informed written consent. Assent was obtained from minors, and their parents signed written consents.
The inclusion criteria were patients with AA of both sexes, aged 6–60 years, not responding to treatment (topical and/ or systemic) for at least 3 months, and off treatment for at least 1 month, prior to the study. The exclusion criteria [ 2 , 3 ] included AA with spontaneous hair regrowth, active scalp inflammation, other scalp or hair diseases, history of hypertrophic scar or keloid, bleeding disorders, and long-term use of anti-coagulant therapy. Pregnant and lactating females and immunocompromised patients were excluded.
Closed envelope method was used to randomly distribute the patients over the study groups. The study included four groups, 15 patients each:
Fractional CO 2 laser was used in ablative mode, using (ATL-250 laser): 10,600nm CO 2 medical laser system built by Advanced Technology Laser Company, Ltd., Shanghai, China. Scanning mode was used with the following parameters: power of 20 Watts, density of PPI 4 (pulses per inch, i.e. array density), and pulse duration/time on of three milliseconds. One pass was applied to the treated area without gaps between pulses, overlap of about 20% was allowed. Scanning area was set to square shape, ratio 9/9, and size 100%. In smaller patches, dimensions were modifiable. Immediately after the laser pass, TrA solution was dripped on the treated area and spread evenly using the blunt end of syringe.
Group II: Micro-needling with Dermapen and triamcinolone acetonide (TrA; 10 mg/ml) [ 5 ] :
Dermapen with a 36-needle disposable tip was used, with 2–2.5 mm long needle depth. The speed of the needles’ movement and of the Dermapen movement was adjusted to the patient’s tolerance to pain. The desired end point was minute pinpoint bleeding points or mild erythema. TrA was applied before, during and after performing micro-needling.
Group III: Fractional carbon dioxide laser (CO 2 Laser) and platelet-rich plasma (PRP) [ 6 ] :
The same laser parameters as group I were used, followed by application of freshly prepared PRP. PRP was prepared using double-centrifugation protocol, which results in higher platelet concentrations, compared to single centrifugation protocol [ 7 ] . For PRP, 10 cc of venous blood were collected from antecubital vein under aseptic conditions, into tubes containing sodium citrate (10:1) as anticoagulant. The initial centrifugation (“soft”/light spin) was done at 2000 rpm for 5 min. The second centrifugation step (heavy/”hard” spin) was carried out at 4000 rpm for 15 min.
Micro-needling was performed as Group II; however, diluted TrA was substituted by PRP.
For all groups:
Each patient received four treatment sessions, spaced three weeks apart [ 1 , 2 , 5 ] , followed by a follow up visit, four weeks after the last treatment session. Prior to the procedure topical anesthetic cream, (pridocaine 2.5% + lidocaine 2.5%) was applied under occlusion for 15–60 minutes. Patients were instructed not to wash their scalp on the treatment day. No treatments for the alopecia were allowed. Topical post-procedure care, including topical antibiotics, emollient or sunscreen could be used.
On the first visit, thorough history was taken, followed by clinical and trichoscopic evaluation [ 2 – 4 , 8 ] . Trichoscopic evaluation [ 9 – 11 ] was performed using a DermLite® DL4 (3 Gen), at 10× magnification in polarized mode.
The patients were assessed clinically and dermoscopically for signs of hair regrowth at each visit, and at the follow up visit. Using Samsung J5 Pro 13-megapixel camera with F1.7 lens, serial digital photographs (clinical and dermoscopic) of the alopecic patches were taken prior to commencement of the treatment, during the treatment sessions and at the end of the treatment. Two independent investigators evaluated the photographs.
Severity of Alopecia Tool (SALT) score at baseline, at each visit, and at end of study, and hair regrowth scale, were used to calculate treatment response [ 2 , 8 ] . Global assessment score [ 8 ] was used to assess the overall improvement, taking into account extent and density of regrowth by SALT score: A0 = no change or further loss, A1 = 1–24% regrowth, A2 = 25–49% regrowth, A3 = 50–74% regrowth, A4 = 75–99% regrowth, and A5 = 100% regrowth. According to the Regrowth scale (RGS), the degree of clinical improvement was evaluated according to a 6-point semi-quantitative score: RGS 0 (re-growth <10%), RGS1 (re-growth 11%–25%), RGS2 (re-growth 26%–50%), RGS3 (re-growth 51%–75%), RGS4 (re-growth ≥75%), and RGS5 (re-growth =100%) [ 12 ] .
Any side effects like atrophy and telangiectasia were observed, clinically and dermoscopically. Patient satisfaction with results of the procedure was graded as satisfied, fair, and unsatisfied. Pain during procedure was graded as: no pain - mild-moderate-severe-pain as bad as it could be [ 13 ] .
Data were fed to the computer and analyzed using IBM SPSS software package version 20.0. ( IBM Corp ) . Significance of obtained results was judged at 5% level.
Demographic Data ( Table (1) )
Table (1) represents different demographic data and patients details, with no significant difference between all groups. There was no significant difference between the studied groups as regards the Baseline Hair loss, using SALT score [ 8 , 9 ] .
Comparison between the four studied groups according to demographic data.
Baseline and Follow-up SALT Scores
There was no significant difference in SALT score at baseline between the 4 groups.
However, SALT score at last follow-up visit showed statistically significant difference between the different groups (P = 0.005). Eighty percent of patients in Pen-Steroid group improved to SALT S0 (no hair loss), compared to only 40% of patients in CO 2 -Steroid and Pen-Steroid groups, and only 13.3% in the CO 2 -PRP group. Pen-Steroid group showed significantly higher improvement compared to CO 2 -PRP group (P = 0.001).
Rate of Hair Regrowth ( Figures 1–5 )
Over subsequent visits, in all treatment groups, there was a shift in the RGS towards higher scores with improved hair regrowth percentages. However, this improvement showed statistical significance between the different treatment groups only at fourth (P = 0.001) and fifth (P = 0.008) visits. At fourth visit, Pen-Steroid group showed maximum improvement with 53.3% of patients scoring RGS4, followed by Pen-PRP group (40% of patients), then CO 2 -Steroid group (33.3% RGS4+5), and finally CO 2 -PRP group with only 13.3% of patients. The difference between Pen-Steroid group and CO 2 -PRP group was significant (P = 0.003). At the final follow up visit, Pen-Steroid group showed maximum improvement with 80% of patients scoring RGS5, followed by Pen-PRP and CO 2 -Steroid group (40% of patients), and finally CO 2 -PRP group with 13.3% of patients. The difference between Pen-Steroid group and CO 2 -PRP group was statistically significant (P < 0.001).
Hair Regrowth Score (RGS) at the End of Study
Improvements in RGS at the end of study, were in favor of using Dermapen for TED (mean RGS 3.93 ± 1.66), compared to CO 2 laser (mean RGS 3.13 ± 1.68), with P = 0.023. Moreover, higher RGS were obtained with TrA as topical medication (mean RGS 4.0 ± 1.53), compared to PRP (mean RGS 3.07 ± 1.76), with P = 0.015.
Dermoscopic Evaluation ( Table (2) ; Figures 6–8 )
At baseline, most common dermoscopic findings were black dots, in 65% of patients, yellow dots and white dots in 45% of patients, exclamation mark hairs in 38.3%, and the least common finding was vellus hair in 11.7% of patients.
Black dots were present at baseline in all groups, and their incidence decreased with treatment. This decrease in black dot, indicating improvement, was statistically significant in all groups (CO 2 -Steroid group P = 0.008, Pen-Steroid group P = 0.002, Pen-PRP group P = 0.031), except in the CO 2 -PRP group.
Exclamation mark hairs were present at baseline in all groups, as third most common dermoscopic finding, and decreased with treatment, especially in Pen-Steroid group (p = 0.002), where the exclamation mark hairs completely disappeared in all patients, after the third treatment session.
Yellow dots were present at baseline in all groups, and decreased with treatment, but without statistical significance.
The decrease in white dots at end of treatment was significantly better in Pen-steroid group compared to the other three groups (P = 0.002). White dots disappeared in 53.3% of affected patients in Pen-steroid group (P = 0.008), compared to only 13.3% in CO 2 -PRP and Pen-PRP groups, and none of the affected patients in the CO 2 -Steroid group.
Vellus hairs showed no statistically significant difference in occurrence, along sessions.
Upright regrowing hairs were the most consistent feature to indicate hair regrowth. It started to appear after the first treatment session, in most patients in all 4 groups, with a statistically significant increase in all study groups (P < 0.001).
Terminal hairs, also started to appear after first treatment session, indicating hair regrowth. There was statistically significant rise from baseline to follow up, in all treatment groups (P < 0.001 in CO 2 -Steroid, Pen-Steroid and Pen-PRP groups; P = 0.002 in CO 2 -PRP group).
Pig tail hairs appeared transiently in the course of treatment. In Pen-Steroid group 60% of patients showed pig tail hairs, which was significantly higher than only 13.3% of patients in CO 2 -PRP group (P = 0.008). Also, patients who showed pig tail hairs in Pen-PRP group where significantly more compared to CO 2 -PRP group (53.3% versus 13.3%, P = 0.020).
The study procedure caused no complications that could be observed by dermoscopy. However, telangiectasia and areas of fibrosis, due to previous intralesional steroid injection, could be visualized dermoscopically.
Relation Between Clinical Response and Dermoscopic Features at Baseline (Table 6)
Amongst all 60 patients, presence of black dots at baseline, could not indicate response to treatment. However, presence of Exclamation mark hairs at base line was significantly related to response (P = 0.024), where it was present in 48.7% of responder patients, compared to only 19% of non-responder ones. Yellow dots were significantly related to poor response to treatment (P = 0.003), present in 71.4% of non-responder patients at baseline, compared to only 30.8% of responder ones. White dots and vellus hairs were represented insignificantly among responder patients and non-responder ones at baseline.
Responders were those with hair regrowth ≥ 75% (ie ≥ RGS 4/global assessment score A4) [ 14 ] .
Onset of Dermoscopic Improvement
Most patients across all treatment groups showed first signs of dermoscopic improvement after first treatment session. Out of the 30 patients receiving TrA, 86.7% showed dermoscopic improvement after first treatment session, compared to 80% of the 30 patients receiving PRP, without statistical significance. The number of patients in Dermapen groups, who showed dermoscopic improvement after first treatment session, was significantly higher than in CO 2 groups (P = 0.010). This indicates that Dermapen might show faster improvement, compared to fractional CO 2 .
Onset of Hair Growth Clinically
Seventy percent of patients in Steroid groups started to show hair regrowth after first treatment session versus 66.7% in PRP groups, without statistical significance. The number of patients in Dermapen group, who started to show hair regrowth after first treatment session, was significantly higher (P = 0.046), than CO 2 groups (80.0% versus 56.7%).
Relation Between Onset of Dermoscopic and Clinical Improvement
Across all 60 patients included in the study, 82% who sowed dermoscopic improvement after first session also showed clinical hair regrowth after first session (statistically significant).
Nevertheless, dermoscopic improvement can herald clinical hair growth. Out of the 22/30 patients in CO 2 groups who showed dermoscopic improvement after first session, 3 started to show clinical hair regrowth after second session and 2 after third session. In Dermapen groups, among the 28 patients who showed dermoscopic improvement after first session, clinical hair regrowth was delayed after second session in 4 patients. Clinical hair regrowth was also delayed to after the second treatment session in four patients in the PRP group. Out of the 26 patients in the Steroid groups who showed dermoscopic improvement after first session, 3 patients showed clinical improvement after the second session and 2 after the third session.
Relation Between Hair Regrowth and Different Parameters
There was no significant correlation between final hair regrowth and patients age, Family history and site of AA patches, in all study groups. Only in CO 2 -Steroid group, Hair regrowth at end of treatment, was significantly higher in patients with first attack of alopecia (100 %), compared to patients who had recurrent disease (65%) (P = 0.031). In CO 2 -Steroid, Pen-Steroid, and Pen-PRP groups there was a negative correlation between the total duration of disease and overall hair regrowth. However, this correlation was significant only in CO 2 -Steroid (rs = −0.678, P = 0.005) and Pen-PRP (rs = −0.593, p = 0.020) groups. The shorter the duration of the current episode of alopecia, the higher the hair regrowth. This negative correlation was significant only in Pen-PRP group (rs = −0.702, P = 0.004). Patients without body hair affection scored higher hair regrowth rates, in all groups. This negative correlation was statistically significant only in the Pen-PRP group (rs = −0.577, P = 0.024). Although not statistically significant, the less the hair loss at baseline, the better the improvement at end of treatment. This was the case in all the groups, with the exception of the Pen-Steroid one. Hair regrowth, at one month follow up, was higher in patients with patchy hair loss. This was significant in Pen-Steroid (P = 0.021) and Pen-PRP (P = 0.022) groups.
Side Effects and Patient Satisfaction
Most patients were satisfied by the results, with no statistical significance between the four study groups (CO 2 -steroid 86.7%, CO 2 -PRP 73.3%, CO 2 -Steroid and Pen-Steroid 80%).
Unlike intralesional steroid injection, no atrophy or telangiectasia were observed. Pain during the procedures, was appreciated as more tolerable compared to injection, in patients who experienced intralesional steroid or PRP injection before. In CO 2 groups, the patients expressed their discomfort as related to heat generated from laser procedure.
No major complications, including secondary infection, ulceration or scaring, occurred in any patient.
A main challenge in AA treatment is directing therapies to the hair follicle. Stratum corneum forms a barrier to topical drug penetration, especially hydrophilic and large molecule drugs [ 15 ] . Fractional lasers [ 4 ] and micro-needling devices may be used deliver drugs to deeper skin layers [ 16 ] , by creating small channels through the stratum corneum to the dermis–microscopic treatment zones (MTZ) for ablative fractional lasers, and physical puncturing in micro-needling [ 17 , 18 ] .
PRP is thought to release growth factors, cytokines, and proteins, from alpha granules, hence stimulating folliculo-genesis and anagen phase [ 19 ] . One limitation in evaluating PRP efficacy for AA is lack of standardized protocols [ 20 ] . Therefore, vertical uniform channels from skin surface into the dermis, may promote uniform placement of PRP in the dermis and eliminate injection-associated pain [ 21 ] . TED can also be used for TrA for the same purposes, with additional advantage of reducing incidence of skin atrophy [ 4 ] . This was in accordance with our study, where atrophy and telangiectasia were not observed.
RGS at end of the study were in favor of using Dermapen, compared to CO2 for TED (P = 0.023). A possible explanation may be occurrence of border of carbonization surrounded by coagulated tissue around the MTZ of fractional CO2 laser, which may partially hinder drug penetration [ 22 ] . On the other hand, dermapen creates transient aqueous microchannels in the stratum corneum, allowing drug permeation by passive diffusion [ 23 ] . Moreover, size of dermapen microchannels are in the range of microns, whereas the macromolecules delivered are usually nanometers in size [ 24 ] . Also, drugs are applied prior, during and after micro-needling, that is more efficacious in drug delivery, compared to spreading the drug only after laser procedure [ 25 ] .
Trichoscopy can be used in the diagnosis and monitoring of treatment in AA [ 26 , 27 ] . Appearance of new Short vellus hair as sign of improvement in some studies [ 26 , 28 ] may actually correspond to the upright regrowing hairs, that were the most consistent features of hair regrowth in our study, as the differentiation between both may be difficult [ 29 ] . Exclamation mark hairs and black dots decreased significantly with treatment. Yellow dots decreased mildly, but without statistical significance. This was in accordance with a study by Ganjoo and Thappa [ 26 ] , indicating that exclamation mark hairs, and black dots are markers of disease activity, and are the first parameters to change in response to therapy, whereas yellow dots were the least responsive [ 26 ] . Trichoscopy is useful in identification of early atrophy and telangiectasia in patients treated with TrA injections. This allowed avoiding reinjection in these areas [ 26 ] .
As with our study, changes in the dermoscopic findings as well as hair RGS were observed from the first follow up [ 30 ] .
Hence, from the present study it can be concluded that, micro-needling and fractional CO 2 laser can be effectively used for TED for AA treatment, and that trichoscopy can be used in AA for evaluation of treatment response.
Supplementary File 1
- Transepidermal drug delivery: a new treatment option for areata alopecia? Issa MC, Pires M, Silveira P, Xavier de Brito E, Sasajima C. J Cosmet Laser Ther.2015;17(1):37-40. CrossRef PubMed
- Safety and efficacy of microneedling with autologous platelet-rich plasma in chronic and stable alopecia areata Chatnallikar N, Asha G, Leelavthy B, Revathi T. J Pak Assoc Dermatol.2018;28(1):59-63.
- A randomized, double-blind, placebo- and active-controlled, half-head study to evaluate the effects of platelet-rich plasma on alopecia areata Trink A, Sorbellini E, Bezzola P, et al. Br J Dermatol.2013;169(3):690-694. CrossRef PubMed
- Fractional carbon dioxide laser in combination with topical corticosteroid application in resistant alopecia areata: A case series Majid I, Jeelani S, Imran S. J Cutan Aesthet Surg.2018;11(4):217-221. CrossRef PubMed
- Alopecia areata-successful outcome with microneedling and triamcinolone acetonide Chandrashekar B, Yepuri V, Mysore V. J Cutan Aesthet Surg.2014;7(1):63-64. CrossRef PubMed
- Combined treatment with fractional carbon dioxide laser, autologous platelet-rich plasma, and narrow band ultraviolet B for vitiligo in different body sites: A prospective, randomized comparative trial Abdelghani R, Ahmed NA, Darwish HM. J Cosmet Dermatol.2018;17(3):365-372. CrossRef PubMed
- Platelet-rich plasma preparation for regenerative medicine: optimization and quantification of cytokines and growth factors Amable PR, Carias RB, Teixeira MV, et al. Stem Cell Res Ther.2013;4(3):67. CrossRef PubMed
- Alopecia areata investigational assessment guidelines--Part II. National Alopecia Areata Foundation Olsen EA, Hordinsky MK, Price VH, et al. J Am Acad Dermatol.2004;51(3):440-447. CrossRef PubMed
- Dermoscopic Findings in 126 Patients with Alopecia Areata: A Cross-Sectional Study Mahmoudi H, Salehi M, Moghadas S, Ghandi N, Teimourpour A, Daneshpazhooh M. Int J Trichology.2018;10(3):118-123. CrossRef PubMed
- Clinical significance of dermoscopy in alopecia areata: analysis of 300 cases Inui S, Nakajima T, Nakagawa K, Itami S. Int J Dermatol.2008;47(7):688-693. CrossRef PubMed
- Hair and scalp dermatoscopy Miteva M, Tosti A. J Am Acad Dermatol.2012;67(5):1040-1048. CrossRef PubMed
- Efficacy and safety of a new clobetasol propionate 0.05% foam in alopecia areata: a randomized, double-blind placebo-controlled trial Tosti A, Iorizzo M, Botta GL, Milani M. J Eur Acad Dermatol Venereol.2006;20(10):1243-1247. CrossRef PubMed
- Graphic representation of pain Scott J, Huskisson EC. Pain.976;2(2):175-184.
- Evaluation of platelet-rich plasma vs intralesional steroid in treatment of alopecia areata Albalat W, Ebrahim HM. J Cosmet Dermatol.2019. CrossRef PubMed
- Skin barrier and transdermal drug delivery Prausnitz MR, Elias PM, Franz TJ, et al. Bolognia JL, Jorizzo JL, Schaffer JV. Dermatology.2012;:2065-2073.
- Fractional photothermolysis: a new concept for cutaneous remodeling using microscopic patterns of thermal injury Manstein D, Herron GS, Sink RK, Tanner H, Anderson RR. Lasers Surg Med.2004;34(5):426-438. CrossRef PubMed
- Microfabricated microneedles: A novel approach to transdermal drug delivery Henry S, McAllister DV, Allen MG, Prausnitz MR. J Pharm Sci.1999;88(9):948. CrossRef PubMed
- Ex vivo histological characterization of a novel ablative fractional resurfacing device Hantash BM, Bedi VP, Chan KF, Zachary CB. Lasers Surg Med.2007;39(2):87-95. CrossRef PubMed
- Applications of platelet-rich plasma in dermatology: A critical appraisal of the literature Lynch MD, Bashir S. J Dermatolog Treat.2016;27(3):285-289. CrossRef PubMed
- Platelet-rich Plasma as a Potential Treatment for Noncicatricial Alopecias Maria-Angeliki G, Alexandros-Efstratios K, Dimitris R, Konstantinos K. Int J Trichology.2015;7(2):54-63. CrossRef PubMed
- Laser-assisted drug delivery for the treatment of androgenetic alopecia: ablative laser fractional photothermolysis to enhance cutaneous topical delivery of platelet-rich plasma - with or without concurrent bimatoprost and/or minoxidil Cohen PR. Dermatol Online J.2019;25(2).
- Laser assisted drug delivery: a review of an evolving technology Sklar LR, Burnett CT, Waibel JS, Moy RL, Ozog DM. Lasers Surg Med.2014;46(4):249-262. CrossRef PubMed
- Super-short solid silicon microneedles for transdermal drug delivery applications Wei-Ze L, Mei-Rong H, Jian-Ping Z, et al. Int J Pharm.2010;389(1–2):122-129. CrossRef PubMed
- The combination of microneedles with electroporation and sonophoresis to enhance hydrophilic macromolecule skin penetration Petchsangsai M, Rojanarata T, Opanasopit P, Ngawhirunpat T. Biol Pharm Bull.2014;37(8):1373-1382. CrossRef PubMed
- Transepidermal Drug Delivery Issa MCA, Casabona G, Santos Torreão P, Roale L, Issa MCA, Tamura B. Daily Routine in Cosmetic Dermatology.2017;:319-326.
- Dermoscopic evaluation of therapeutic response to an intralesional corticosteroid in the treatment of alopecia areata Ganjoo S, Thappa DM. Indian J Dermatol Venereol Leprol.2013;79(3):408-417. CrossRef PubMed
- Platelets rich plasma versus minoxidil 5% in treatment of alopecia areata: A trichoscopic evaluation El Taieb MA, Ibrahim H, Nada EA, Seif Al-Din M. Dermatol Ther.2017;30(1). CrossRef PubMed
- Clinical and dermatoscopic patterns of alopecia areata: a tertiary care centre experience Hegde SP, Naveen KN, Athanikar SB, Reshme P. Int J Trichology.2013;5(3):132-136. CrossRef PubMed
- Hair shafts in trichoscopy: clues for diagnosis of hair and scalp diseases Rudnicka L, Rakowska A, Kerzeja M, Olszewska M. Dermatol Clin.2013;31(4):695-708. CrossRef PubMed
- Dermoscopic evaluation of therapeutic response to intralesional triamcinolone acetonide in the treatment of Alopecia areata Srivastava S, Goyal S, Dhillon K, Singh N. Int J Adv Med.2017;4(4):1175-1183.