A Systematic Review of the Outcome of Hair Transplantation in Primary Scarring Alopecia

Scarring alopecia, otherwise known as cicatricial alopecia, refers to irreversible inflammatory follicular damage associated with scarring and hair loss. Primary scarring alopecias are generally subdivided into three categories: lymphocytic (lichen planopilaris [LPP], frontal fibrosing alopecia [FFA], central centrifugal cicatricial alopecia [CCCA], and pseudopelade of brocq), neutrophilic (folliculitis decalvans, tufted folliculitis, and dissecting cellulitis), and mixed lymphocytic/neutrophilic (folliculitis keloidalis, folliculitis necrotica, and erosive pustular dermatosis) [1]. Primary scarring alopecia are more common in women, who present typically in ages between 30 and 50 years [2]. Though the exact pathogenesis of primary scarring alopecia differ among particular diagnoses, the predominant similarity is that immune cells permanently damage the follicular stem cell reservoir of the outer root sheath, or bulge region, of hair follicles [3].

Current therapeutic regimens aim to slow or inhibit the progression of the disease with local or systemic immunomodulation. First-line treatments are topical steroids, such as fluocinonide, and clobetasol lotion or cream, and intralesional triamcinolone acetonide [4]. Antibiotics, -retinoids, hydroxychloroquine, and mycophenolate are commonly used to adjunct corticosteroids and decrease inflammation in rapidly progressive disease [5].

Hair transplants are used by many patients as a treatment option; however, there are no clear guidelines regarding its implementation. The philosophy of this surgical technique relies on balding-resistant, hair-abundant tissue surviving after it is transplanted to the balding skin. Hair restoration procedures have dramatically evolved to incorporate minute precision. Currently, follicular unit extraction (FUE) is the gold standard method due to the ability to individually pick desirable follicular units, no suturing is required, and minimal scarring occurs [6].

Though serious complications of hair transplants are rare, the development of safety precautions has helped graft survival rates to improve. Among the most determinant factors are the type of graft preservation solution and perioperative medical treatment of recipient areas used [7]. A pre-surgery hair transplant test, in which one FU is transplanted alone and observed for significant adverse effects or inability to thrive, is recommended. The survival rate of transplanted hair is determined by factors such as oxidative stress, infection, edema, and recipient or donor dominance, which refers to the likelihood of the surrounding balding-prone tissue to effect the transplanted tissue [8]. Hair transplantation in scarring alopecia has low graft survival rates (50%) compared to non-scarring alopecia (> 90%); some suspect this is due to recipient area dominance [9]. This paper seeks to review the current literature on the outcomes of hair transplantation in scarring alopecia.

A primary literature search was conducted using PubMed with the search terms (“cicatricial alopecia” OR “scarring alopecia” OR “central centrifugal cicatricial alopecia” OR “morphea en coup de sabre” OR “discoid lupus erythematosus” OR “folliculitis decalvans” OR “lichen planopilaris” OR “frontal fibrosing alopecia” OR “pseudopelade of brocq” OR “tufted folliculitis” OR “dissecting cellulitis” OR “folliculitis keloidalis” OR “hair loss”) AND (“hair transplant” OR “hair transplantation” OR grafts OR “follicular unit extraction”).

Clinically relevant systematic reviews, randomized controlled trials, and case studies were included. Only articles from 1960s to present, which met the following inclusion criteria were included in this review: the report specified type of scarring alopecia that was studied, the authors included well-defined clinical outcomes of hair transplant treatment, and the manuscript was written in English. Reviewed studies were graded using the Oxford Center for Evidence-Based Medicine 2011 Levels of Evidence [10].

The primary literature search, outlined above, provided a total of 359 articles from PubMed. After removing duplicates and screening for clinically relevant material, a total of 19 reports were reviewed. One of the articles was found in the references of an article. Once articles were screened for clinically relevant material, four case studies were excluded due to ambiguous outcomes, combined scarring and non-scarring hair transplantation results, or languages other than English. A total of 15 reports were included for review. Of these studies, 6 are case reports and 8 are case studies (involving 2+ patients). There are a total of 34 patients (24 female, 5 male, 5 unknown). A total of 26 patients experienced moderate to positive results (78% positive outcome rate), as defined by the published clinical reports, while 8 patients experienced negative results or recurrence of disease. Primary literature search results are shown in the PRISMA Flow Diagram (Fig. 1). All included reports were rated a level 4 on the Oxford Levels of Evidence.

Among the 15 reports included, CCCA, discoid lupus erythematosus (DLE), FFA, folliculitis decalvans, LLP, morphea coup de sabre, and pseudolade of brocq were discussed. Hair transplantation methods and peri-operative care varied between studies. Transplant methods discussed included FUE, donor strip method, punch graft method, and otherwise not specified methods. Out of a total of reported 34 study patients, 26 patients had moderate to positive results while 8 patients experienced unsatisfactory results or recurrence of illness after hair transplantation. A summary of each article included in this review is provided in Table 1.

This systematic review aimed to evaluate the efficacy of hair transplantation in patients with primary scarring alopecia. A review of 15 case studies and reports revealed a 76% positive outcome rate with 8 of 34 patients experiencing negative results, including those with a diagnosis of LPP or FFA.

Hair transplantation has been successful in 3 patients previously diagnosed with CCCA [9, 11]. The cases employed a combination of pre-transplant tests, recipient site biopsy, and at least 6 months to 2 years of anti-inflammatory control post-transplant.

Although the scarring hair loss seen in morphea en coup de sabre can be categorized as a secondary scarring alopecia, we included the published hair transplantation results for completeness in this review. Two patients with morphea en coup de sabre are reported to have positive hair growth at 2 years post-transplant [12, 13]. Neither patient responded to systemic anti-inflammatory treatment with corticosteroids and hydroxychloroquine, suggesting that additional inflammatory control may not be required for graft survival in this condition.

There is old literature on successful hair transplantation without significant pre- or post-surgical treatment in 8 DLE patients who underwent punch graft transplants and were followed for the next 3 years [14]. The patients experienced an average of 72% graft survival. One patient with folliculitis decalvans is documented as having moderately successful hair growth results with FUE [11]. The patient applied minoxidil lotion for 6 months and observed a 40% graft uptake. This supports the claim that post-transplant topical minoxidil alone is at least partially efficacious in promoting graft survival. Patients with folliculitis decalvans who undergo hair transplantation in the future may also benefit from a combination of anti-inflammatory treatment and topical minoxidil.

LPP variants include classical, FFA, and Graham-little-Piccardi-Lasseur syndrome and manifest as hyperkeratosis, loss of follicular ostia, and perifollicular erythema. Five case studies report that 6 of 8 patients with LPP experienced good or moderate graft survival rates [11, 15-18]. Although inconsistent follow-up periods (none to 3 years) make comparison difficult.

Literature regarding FFA and hair transplantation reports a majority of failed transplant vitality [15, 19-22]. Although hair growth for the patients who had successfully traversed at least 2 years of stable disease was initially excellent, recipient dominance lead to a recurrence of FFA at graft sites by 4 years post-transplant in multiple cases [20-22]. As with patients with CCCA, efficacy of hair transplantation in FFA appears to be directly correlated with the stability of inflammation prior to surgery. Suggestions to maximize assurance that a patient with FFA is a good candidate for hair transplantation include assessing disease activity with biopsies, waiting 2–5 years after hair loss ceases, using anti-inflammatory topical or intralesional medications pre- and post-surgery, and continuing follow-up to monitor efficacy.

Pseudopelade of Brocq (PPB) is a chronic primary scarring alopecia that is classically void of clinical symptoms or signs of inflammation, and is considered by some a variant of LPP or DLE [23]. Three patients experienced positive results with hair transplantation [11, 24, 25]. One patient used 5% minoxidil lotion for 6 months post-surgery and observed a 60% graft uptake, although no long term follow-up was reported [11]. Similar to patients with LPP, this case report supports the use of topical minoxidil post-transplant, as a treatment option for PPB.

The literature reports compiled here emphasize the need for control of scarring alopecias when considering hair transplant surgery [6, 24]. However, the authors were unable to find evidence on how to precisely diagnose disease activity or the timing post-disease-activity when performing surgery is appropriate. The commonly suggested “two year” rule for hair transplant surgery post-disease-activity was not substantiated in this review [4, 15, 25]. There was a wide versatility of topical, intralesional, and systemic medications necessary for proper immunomodulation of graft recipient tissue. This review raises the need for affirming that inflammatory and scarring diseases on the scalp are well controlled, and defining the timing for a minimum of 2 and recommended up to 5 years prior to surgery.

This review was limited by the scarcity of documentation on hair transplantation in patients with scarring alopecia. Measurement of graft survival, follow-up time, as well as peri-transplant medication protocols are not yet standardized and should be developed through further observational studies and case series. There is an obvious lack of robust and well-controlled scientific studies on hair transplantation in scarring alopecia patients. The biggest challenge encountered in this review is the positive reporting bias in the literature where only cases with viable and positive outcomes are reported. Thus, we conclude that no concrete, evidence-based recommendations can be made regarding this topic at this time. We need better studies to elucidate the role of hair transplantation in treating primary scarring alopecia.

Hair transplantation surgery may represent a viable treatment option for controlled CCCA, en coup de sabre, DLE, pseudolade de brocq, and folliculitis decalvans, whereas LPP and FFA have reported both negative and positive results. However, data must to be interpreted with caution, as we suspect a positive-result publication bias and a higher incidence of negative transplant outcomes in this population than what is published.

The authors have no conflicts of interest to disclose.