Secondary Logo

Journal Logo

Original articles

Clinical and histopathological evaluation of percutaneous collagen induction (dermaroller) in the treatment of postacne scars

Lotfi, Ranyaa; Moneib, Hodaa; Yehia, Hananb

Author Information
Journal of the Egyptian Women's Dermatologic Society: September 2013 - Volume 10 - Issue 3 - p 152-159
doi: 10.1097/
  • Free



Acne vulgaris is one of the most frequent chronic skin diseases and the most common dermatologic disorder of adolescents 1. Despite effective treatment of acne, scarring occurs in almost 95% of patients irrespective of the severity of acne. The scarring causes long-term morbidity 2. It is a psychologically devastating condition and the affected patient invariably suffers from low self-esteem and many other psychological adverse effects 3.

Facial scarring has always been a challenge to treat and there are many treatment options to manage the condition. However, the majority of such treatment options have the limitation of either being marginally effective or having considerable morbidity. Treatment options such as laser resurfacing or dermabrasion that offer significant improvement are invariably associated with considerable morbidity and downtime. However, treatments such as nonablative lasers and microdermabrasion that are associated with minimal downtime do not show the same level of efficacy 4. New treatments are being introduced to overcome these limitations.

One such treatment is percutaneous collagen induction (PCI) with a dermaroller. There are now some clinical studies in the literature documenting the favorable clinical and histopathological response after dermaroller therapy. However, there are definitely few objective clinical trials on the efficacy of this treatment modality 4.

Postacne facial scars have been classified into many morphological types and the ideal treatment option depends on the type of scars. Acne scars may be atrophic or hypertrophic. The former type is classified into ice pick, boxcar, or rolling scars 5. Goodman and Baron 6 recommended a classification scheme on the basis of the severity of acne scars, where four different severity grades are identified. Once the scar type has been defined, appropriate treatment protocols can be developed. In order to confirm the usefulness of collagen induction therapy (CIT) in acne scarring treatment, this study objectively assessed the efficacy of the dermaroller clinically and also histopathologically in the treatment of postacne rolling, boxcar, and ice-pick scars.

Patients and methods

This long-term (1-year) prospective interventional study included 30 patients with postacne scars and was carried out at the Dermatology Outpatient Clinic, Ain shams University Hospitals, from November 2011 to November 2012. All patients provided a written informed consent, and the Ethics Committee of Ain Shams University, Cairo, Egypt, approved the study protocol.

The study included 30 patients with variable types and severity grades of atrophic postacne scars. Their Fitzpatrick skin phototyping was selected to be III and IV. All patients received complete information on the steps of treatment. Patients excluded from the study were those with active acne or hypertrophic acne scars, any other skin disease, keloidal tendency, bleeding disorders, history of application of topical retinoids or use of systemic retinoids or any other scar treatment within 6 months before the study, pregnant patients, or those with a history of corticosteroid or anticoagulant treatment.

Atrophic acne scarring was subtyped into ice pick, boxcar, and rolling scars according to the Jacob et al.7 classification, and the severity was graded according to Goodman and Baron 6 by two trained dermatologists who reassessed the grade of severity 8 weeks after the last session. Clinical documentation was performed by sequential photographs. Shots were taken for the area of interest in each patient before the start of treatment (pretreatment) and immediately before each session for five sessions and the last shots were taken 8 weeks after the last session. The assessment of severity was also performed photographically. Photographs were taken using a Canon IXUS 95015 digital camera (Canon Inc., USA), 8 mega pixels.

The dermaroller used in this study was MT15, manufactured by Clinic Resolution Laboratory Inc.(Beverly Hills, California, USA). This dermaroller consists of a handle with a cylinder studded all around with 192 fine, stainless-steel needles 1.5 mm in length. Treatments were performed at monthly intervals for five sittings. A topical anesthetic cream (EMLA cream, a eutectic mixture of lidocaine and prilocaine) was applied in a thick layer on the face for 1 h. It was then removed with sterile water. The face was then painted with a 1% povidone iodine solution and then removed with sterile water. Dermarollers were rolled on the skin with pressure in vertical, horizontal, and two diagonal directions (about 10 times per direction). The endpoint for any treatment session was the presence of uniform bleeding points over the scarred area. In patients with deep-seated scarring, the skin was stretched in a direction perpendicular to the dermaroller movement so that the base of the scars could also be reached. After treatment, the bleeding was controlled with light pressure with sterile gauze and a 1% fusidic acid ointment was then applied on the treatment area and patients were advised to use it twice daily for 2–3 days. They were also instructed to avoid sun exposure and to use sunscreens with SPF greater than 30 regularly.

Two-millimeter punch skin biopsies were obtained from acne scars located in front of the ear and treated with the dermaroller, one before treatment and the other 8 weeks after the last session. The biopsies were taken under local (lidocaine 2%) anesthesia, fixed in a 10% formalin solution, dehydrated with alcohol, and embedded in paraffin. Four-micron thickness sections were stained with hematoxylin and eosin (H&E), Masson’s trichrome stain, and silver stain.

Evaluation of treatment outcome was carried out according to clinical improvement in postacne scars, histopathological evaluation, patients’ self-assessment, and the complications experienced by the patients.

Clinical evaluation

In this study, the change in the severity or grading of scars (graded according to Goodman and Baron 6) after treatment was assessed photographically by the consensus of four independent observers; two were dermatologists and the other two were nurses. If the change in the grade of severity was reduction by two grades, the improvement was considered excellent; if the reduction was only by one grade, the improvement was considered good; and if there was no reduction in the grade of acne scarring the improvement was considered poor 4. Patients were also given a preformed questionnaire at the end of the follow-up period, and they were asked to rate the improvement of their scars on a 10-point scale. A rating above 6 was graded as an excellent response, a rating between 4 and 6 indicated a good response, and a rating below 4 indicated a poor response. An assessment of the treatment protocol on the part of the patients was also thus obtained.

Histopathological evaluation

Microscopic scale bar measurement was used to compare the epidermal thickness with H&E before and after treatment. Masson’s trichrome stain and silver-stained sections were examined using an image analysis system (Leica Microsystems Imaging Solutions Ltd, Cambridge, UK). This station included a Leica Q 500 IW (Leica DM LB, Leica Microsystems, Austria) photomicroscope with position captors and a CCD video camera module N 50 (JVC TK-C 1380, JVC Victor Company, Tokyo, Japan). Images were captured using a ×20 magnification objective, digitized following light intensity equilibration, and analyzed as RGB 24-bit images. Ten fields were selected randomly from slides stained with Masson’s trichrome stain that did not include large nonconnective tissue elements. From every section, an image of 256 gray levels was obtained and converted into a binary image showing collagen fibers as blue. This image was processed and the number of collagen fibers in every field and the area filled by them were determined, with results expressed as collagen fibers in μm2 and the percentage of the field containing the collagen fibers. From silver-stained sections, five fields that did not include large nonconnective tissue elements were selected randomly. From every section, an image of 256 gray levels was obtained and converted into a binary image showing elastic fibers as brown. Measurements were performed as those for collagen fibers. Special stains were used to compare the quality, quantity, and arrangement of collagen and elastic fibers before and after treatment.

Assessment of complications: any complication in the post-treatment period was recorded.

Patients were asked immediately after each session to evaluate pain caused by the procedure, which was classified on the basis of a 100-point pain score according to the Trelles arbitrary score 8 as 0=no pain, <25=mild, 25–50=moderate, 50–75=severe, and >75=significant.

Postprocedure erythema was classified as mild, moderate, marked, and severe on the basis of the time taken until the erythema had resolved completely (1–2, 2–5, 5–12, and >12 h, respectively) 9.

Hyperpigmentation was evaluated as mild (lasted 7 days), moderate (lasted 2–4 weeks), marked (lasted 4–6weeks), and severe (lasted >6 weeks) on the basis of the time taken until the hyperpigmentation had resolved completely 10.

Statistical methods

The data were collected, coded, and entered into a personal computer IBM compatible 2.6 GHz (International Business Machines Corporation, New York, New York, USA). The data were analyzed using the program statistical package for social science under windows version 11.0.1 (SPSS Inc., Chicago, Illinois, USA).

Quantitative data were expressed as mean±SD, whereas qualitative data were expressed as frequency and percentage. Student’s t-test was used to assess the statistical significance of the difference between the means of the two study groups. The χ2-test was used to examine the relationship between two qualitative variables. A P-value of 0.05 was considered significant.


Among the 30 patients with atrophic postacne scars included in the study, 18 were men and 12 were women, with ages ranging from 19 to 44 years. Fifteen patients (50%) had combined ice pick, rolling, and boxcar acne scars, 12 (40%) had combined rolling and boxcar scars, and three (10%) had only ice-pick scars. In all patients, scars were distributed on both cheeks, in 12 patients scars were also distributed on the forehead, and in six patients scars were also found on the chin.

After the first session of CIT, all patients started to notice smoother facial skin and a slight reduction in lesion severity. At the start of the study, the assessment showed grade II scarring in six patients (20%), grade III scarring in 15 patients (50%), and grade IV scarring in nine patients (30%). The six patients (100%) with grade II scars showed a good response to treatment (reduction from grade II to grade I). They had combined rolling and boxcar scars. In the 15 patients with grade III scarring, an excellent response was noted in six of them (40%) (reduction from grade III to grade I), who had combined rolling and boxcar scars, whereas in the other nine patients (60%) who had combined ice pick, rolling, and boxcar scars a good response was achieved (reduction from grade III to grade II). Six patients (66.7%) with grade IV scarring achieved a good response on assessment (reduction to grade III). They had combined ice pick, rolling, and boxcar scars. The other three patients (33.3%) with grade IV scarring only had ice pick scars and could not achieve any reduction in the grading of their scars and the response was considered poor. Thus, overall, six (20%) of the total of 30 patients showed an excellent response to dermaroller treatment whereas 21 others (70%) achieved a good response. Only three (10%) patients of the total of 30 failed to show a significant response to treatment (Table 1).

Table 1
Table 1:
Comparison between the severity grade of acne scars before and after treatment

On comparing grades of acne scarring before and after treatment, it was found that the reduction rate in grades of acne scars after treatment with the dermaroller was highly significant (P=0.01) (Table 1).

Fifty percent of patients with only rolling and boxcar scars achieved an excellent improvement whereas all patients with combined ice pick, rolling, and boxcar scars achieved good improvement. The only patients who could not achieve any improvement were those who had ice-pick scars (Table 2).

Table 2
Table 2:
Comparison between improvement in different morphological types of acne scarring

Accordingly, the best results were achieved in patients with no ice-pick scars. Thus, when dividing patients into two groups, all patients without ice picks scars (100%) achieved good to excellent responses, whereas all patients with ice picks scars (100%) achieved poor to good responses, and this difference was highly statistically significant.

According to the patients’ response record at the end of the treatments, 21 patients (70%) rated their response as excellent, six (20%) as good, and three patients (10%) as poor (Figs 1 and 2).

Figure 1
Figure 1:
Excellent response after treatment with the dermaroller.
Figure 2
Figure 2:
Good response after treatment with the dermaroller.


Hematoxylin and eosin

After treatment with the dermaroller, the epidermis became acanthotic, with some areas of spongiosis. There was a 50% increase in the epidermal thickness as the mean epidermal thickness after treatment was 1.5 mm, associated with a striking development of rete ridges. The dermis showed increased depth with an increase in the number and density of collagen fibers. Interfibrillary spaces decreased and there was good linear orientation of the fibers parallel to the dermoepidermal junction. All scars treated with the dermaroller showed scattered spindle-shaped fibroblasts in the papillary dermis and prominent collagen remodeling. The histopathologic evaluation showed improvement in the condition of the epidermis and dermis in patients who were treated with the dermaroller for five sessions (Fig. 3a and b).

Figure 3
Figure 3:
(a) Untreated postacne scar showing thinning of the epidermis, increased interfibrillary spaces, and random deposition of collagen and mild perivascular inflammatory infiltrate in the dermis (H&E, ×200). (b) Postacne scar after treatment showing increased number and density of collagen fibers, linear orientation of fibers, scattered spindle-shaped fibroblasts in the papillary dermis, and increased perivascular inflammatory infiltrate (H&E, ×200). H&E, hematoxylin and eosin.

Masson’s trichrome stain to demonstrate collagen fibers

There was a 53.2% mean increase in the collagen fiber content in the papillary dermis of patients. The range of increase was from 42.2 to 64.9% and this increase was found to be significant statistically (P<0.05). Collagen fibers appeared regularly and linearly arranged as thick wavy branching bundles (Table 3 and Fig. 4a and b).

Table 3
Table 3:
Comparison between collagen content before and after treatment
Figure 4
Figure 4:
(a) Untreated postacne scar showing dermal collagen randomly deposited with decreased number and density of fibers (Masson trichrome, ×200). (b) Postacne scar after treatment with the dermaroller showing markedly increased number and density of collagen fibers. Interfibrillary spaces are markedly diminished, with a linear orientation of collagen fibers (Masson trichrome, ×200).

Silver stain to demonstrate elastic fibers

There was a 65.4% mean increase in the elastic fiber content in the papillary dermis of patients. The range of increase was from 46.9 to 79.2%. However, this increase was statistically insignificant (P>0.05) (Table 4 and Fig. 5a and b). Elastic fibers were increased in number and density, with a linear and regular orientation.

Table 4
Table 4:
Comparison between elastin content before and after treatment
Figure 5
Figure 5:
(a) Untreated postacne scar showing decreased number of elastic fibers (silver, ×200). (b) Postacne scar after treatment with the dermaroller showing markedly increased number and density of elastic fibers with a linear orientation of fibers (silver, ×200).


Immediately after treatment, 18 patients (60%) reported moderate pain that lasted for 10 min and 12 patients (40%) reported severe pain lasting for 10 min. All patients were almost pain free at about 30 min after each session. After each session of treatment, the facial skin appeared reddened and swollen; 27 patients (90%) experienced marked erythema [which remained for about 12 h after the session and three patients (10%) reported that the redness and swelling disappeared in 1–2 days (severe erythema)]. Hyperpigmentation was not reported in any patient following treatment. No other adverse effects were noted in any patient. No patient reported any interference in his/her daily activities in the immediate post-treatment period and the only change noted was a mild crusting that persisted for 1–2 days.


CIT using the dermaroller is a simple technique and can have led to an improvement in acne scars. According to the literature, the full result may take 8–12 months to achieve as the deposition of new collagen occurs slowly. An ideal treatment for acne scars should include documentation of a significant improvement with a low risk and little downtime for the patient.

The overall clinical improvement in different types of postacne scars in this study showed that six of the total of 30 patients (20%) achieved an excellent response to PCI therapy, whereas 21 others (70%) achieved a good response. Only three patients (10%) of the total of 30 failed to show a significant response to treatment. These results are in accordance with a study by Majid 4, in which 36 patients with atrophic facial scarring were treated with the dermaroller by almost the same protocol. The end result showed that of 36 patients, 34 achieved a reduction in the severity of their scarring by one or two grades (good to excellent response), with no significant adverse effects. However, the present study was limited to the treatment of postacne scars whereas the other study included post-traumatic, postvaricella, and postherpetic scarring. Also, Majid 4 did not include histopathological evaluation.

A good to excellent response was found in rolling and boxcar scars (50% of patients achieved good improvement and the other 50% achieved excellent improvement) whereas ice-pick scars showed poor-to-moderate improvement. A study by Fabbrocini et al.11 achieved better overall clinical improvement (100%) (without specification of degrees of improvement) compared with 90% clinical improvement in the present study, which may be attributed to the fact that they enrolled patients with rolling and not ice-pick scars. In 2010, Fabbrocini et al.12 reported similar histopathological findings, in the form of thickening of skin and a marked increase in new collagen and elastin.

The results were also almost in agreement with those of Aust et al.13, who carried out a retrospective study of 480 patients with wrinkles, scars, and stretch marks in South Africa and Germany to confirm the collagen induction benefit of microneedling. Their evaluation indicated a 60–80% improvement. Lower improvement rates were observed in a study carried out on atrophic acne scars in 31 Thai patients 14. Almost the same protocol was applied; however, an improvement of more than 50% was observed in only 67.74% of cases in contrast to an improvement of more than 50% in 90% of patients in the present study. The only difference is that their study included skin phototype V whereas our study only included skin phototypes III and IV.

Interestingly, patients were more satisfied and reported higher improvement grades than the observers, adding another success value to PCI.

Histologically, depressed postacne scars show loss of collagen resulting in a downward pull of the epidermis. Ice-pick scars also have decreased elastin and an increase in type III collagen. During the remodeling phase, type III collagen is gradually replaced by type I collagen, which is typically the most abundant collagen in the dermis 15.

Clinical effectiveness of the dermaroller is based on the induction of synthesis of new collagen and other components of the extracellular matrix. Therefore, histologically, the goal of treatment is induction of the proliferative phase in tissue repair that consists of stellate-appearing fibroblasts and myofibroblasts, which participate in active production of extracellular matrix components including collagen I and III 16.

The histopathologic evaluation in this study showed improvement in the condition of the epidermis and dermis, with increased density and regular arrangement of collagen and elastic fibers. Other studies also showed that after treatment, the skin was indistinguishable from normal skin and that the epidermis showed more dermal papillae. The skin became thicker, with considerably increased collagen deposition and significantly more elastin 12,17.

No adverse effects were noted in any patient, except for transient pain during the session and mild erythema that was tolerable for all patients. We did not record any post-treatment folliculitis, as did other authors in 6.45% of the patients 14. This might be because of the presence of some active acne lesions or inadequate sterilization before treatment.

Microneedling is contraindicated with anticoagulant therapies, active skin infections, collagen, or filler injections in the previous 6 months and a history of hypertrophic and keloidal scars 18.

The authors concluded that CIT has undisputable advantages compared with conventional methods 17,19. Most importantly, the epidermis remains intact because it is not damaged, eliminating most of the risks and negative side effects seen with chemical peeling or laser resurfacing. A study carried out by Kono et al.20 showed that the rate of postinflammatory hyperpigmentation was significantly higher after treatment with fractional lasers and the recovery time was more than 1 week 21.

Most of the studies on the fractional laser resurfacing showed that the overall improvement ratio ranged from 43 to 80% 12,22,23, which is comparable to the overall improvement rates for the CIT. Also, the high cost of fractional laser equipment had discouraged wide acceptance of this laser in most developing countries 18.

In this study, a good to excellent response was achieved in 27 of 30 patients (90%). More severe grades (grade IV scars) showed a poor response compared with grades II and III; also, ice-pick scars showed little improvement. However, these scars are difficult to treat even by other modalities such as lasers and may need surgical correction 12. This difficulty might be because of the downward pull of fibrous tissue at the base of ice-pick scar and the loss of both collagen and elastin. There were no significant adverse effects or downtime. This is in contrast to other interventional treatment modalities, with the added advantages of being easy to perform with affordable equipment.


The authors thank to Dr Nafeesa El Badawi, Professor of Pathology, Ain Shams University for histopathological assistance and assessment of this work.

Conflicts of interest

There are no conflicts of interest.


1. Uslu G, Şendur N, Uslu M, Şavk E, Karaman G, Eskin M.Acne: prevalence, perceptions and effects on psychological health among adolescents in Aydin, Turkey.J Eur Acad Dermatol Venereol2008;22:462–469.
2. Jemec GBE, Jemec B.Acne: treatment of scars.Clin Dermatol2004;22:434–438.
3. Orentreich D, Orentreich N.Acne scar revision update.Dermatol Clin1987;5:359–368.
4. Majid I.Microneedling therapy in atrophic facial scars: an objective assessment.J Cutan Aesthet Surg2009;2:26–30.
5. Alam M, Dover JS.Treatment of acne scarring.Skin Therapy Lett2006;11:7–9.
6. Goodman GJ, Baron JA.Postacne scarring: a qualitative global scarring grading system.Dermatol Surg2006;32:1458–1466.
7. Jacob CI, Dover JS, Kaminer MS.Acne scarring: a classification system and review of treatment options.J Am Acad Dermatol2001;45:109–117.
8. Trelles MA, Allones I, Luna R.Facial rejuvenation with a nonablative 1320 nm Nd:YAG laser: a preliminary clinical and histologic evaluation.Dermatol Surg2001;27:111–116.
9. Hee JK, Tae GK, Yeon SK, Jin MP, Ju HL.Comparison of a 1550 nm Erbium:Glass fractional laser and a chemical reconstruction of skin scars (CROSS) method in the treatment of acne scars: a simultaneous split-face trial.Lasers Surg Med2009;41:545–549.
10. Khunger N.Standard guidelines of care for acne surgery.Indian J Dermatol Venereol Leprol2008;74SupplS28–S36.
11. Fabbrocini G, Fardella N, Monfrecola A, Proietti I, Innocenzi D.Acne scarring treatment using skin needling.Clin Exp Dermatol2009;34:874–879.
12. Fabbrocini G, Annunziata MC, D'Arco V, De Vita V, Lodi G, Mauriello MC, et al..Acne scars: pathogenesis, classification and treatment.Dermatol Res Pract2010;2010:893080. doi: 10.1155/2010/893080.
13. Aust MC, Fernandes D, Kolokythas P, Kaplan HM, Vogt PM.Percutaneous collagen induction therapy: an alternative treatment for scars, wrinkles, and skin laxity.Plast Reconstr Surg2008;121:1421–1429.
14. Niwat P.Percutaneous collagen induction with dermaroller for management of atrophic acne scars in 31 Thai patients.J Cosmetic Dermatol2009;121:1421–1429.
15. Goodman GJ.Management of post-acne scarring: what are the options for treatment?Am J Clin Dermatol2000;1:3–17.
16. Gabbiani G.The myofibroblast in wound healing and fibrocontractive diseases.J Pathol2003;200:500–503.
17. Fernandes D, Signorini M.Combating photoaging with percutaneous collagen induction.Clin Dermatol2008;26:192–199.
18. Chua S-H, Ang P, Khoo LSW, Goh C-L.Nonablative 1450-nm diode laser in the treatment of facial atrophic acne scars in type IV to V Asian skin: a prospective clinical study.Dermatol Surg2004;30:1287–1291.
19. Lee HS, Lee JH, Ahn GY, Lee DH, Shin JW, Kim DH, Chung JH.Fractional photothermolysis for the treatment of acne scars: a report of 27 Korean patients.J Dermatolog Treat2008;19:45–49.
20. Kono T, Chan HH, Groff WF, Manstein D, Sakurai H, Takeuchi M, et al..Prospective direct comparison study of fractional resurfacing using different fluences and densities for skin rejuvenation in Asians.Lasers Surg Med2007;39:311–314.
21. Krader CG.Fractional laser benefits differ in treating acne scars in Asian skin. Cosmetic Surgery Times, 1 June 2010.
22. Alster TS, Tanzi EL, Lazarus M.The use of fractional laser photothermolysis for the treatment of atrophic scars.Dermatol Surg2007;33:295–299.
23. Chapas AM, Brightman L, Sukal S, Hale E, Daniel D, Bernstein LJ, Geronemus RG.Successful treatment of acneiform scarring with CO2 ablative fractional resurfacing.Lasers Surg Med2008;40:381–386.

acne; acne scars; dermaroller; percutaneous collagen induction

© 2013 Egyptian Women's Dermatologic Society