Abstract and Introduction
Primary cicatricial alopecias (PCAs) are a poorly understood group of disorders that result in permanent hair loss. Clinically, they are characterized not only by permanent loss of hair shafts but also of visible follicular ostia along with other visible changes in skin surface morphology, while their histopathological hallmark usually (although not always) is the replacement of follicular structures with scar-like fibrous tissue. As hair follicle neogenesis in adult human scalp skin is not yet a readily available treatment option for patients with cicatricial alopecias, the aim of treatment, currently, remains to reduce symptoms and to slow or stop PCA progression, namely the scarring process. Early treatment is the key to minimizing the extent of permanent alopecia. However, inconsistent terminology, poorly defined clinical end-points and a lack of good quality clinical trials have long made management of these conditions very challenging. As one important step towards improving the management of this under-investigated and under-serviced group of dermatoses, the current review presents evidence-based guidance for treatment, with identification of the strength of evidence, and a brief overview of clinical features of each condition. Wherever only insufficient evidence-based advice on PCA management can be given at present, this is indicated so as to highlight important gaps in our clinical knowledge that call for concerted efforts to close these in the near future.
The primary cicatricial alopecias (PCAs; synonyms: scarring alopecias; permanent alopecias) are a diverse group of inflammatory hair disorders of essentially unknown aetiology that result in irreversible hair loss. They are characterized clinically by permanent loss not only of hair shafts but also of visible follicular ostia (Figure 1) and pathologically by replacement of follicular structures with fibrous tissue.[1,2,3,4,5] As PCAs represent, at least to date, a state of irreversible skin damage whose further progression must be prevented, and as PCA can have major psychosocial consequences for affected patients and may even herald underlying serious systemic disease, these dermatoses require and deserve the full attention of every dermatologist.
Alopecia with loss of visible follicular ostia, perifollicular erythema and hyperkeratosis (diagnosis = lichen planopilaris).
In PCA the hair follicle is the main target of the disease process whereas in secondary cicatricial alopecias the follicular damage occurs indirectly from events occurring outside the follicular unit, e.g. as a result of trauma or infection. In both PCA and secondary cicatricial alopecia, the permanency of hair loss results from the acquired inability of damaged hair follicles to regenerate after injury, most likely as a result of irreversible damage to epithelial hair follicle stem cells residing in the bulge area of the outer root sheath (ORS).[3,6,7]
Management of PCA is often quite challenging. Poor correlation between clinical and pathological features has resulted in problems with disease classification, with incomplete or inaccurate disease definition and inconsistent use of terminology in the medical literature. Even histopathological diagnosis of PCA can be quite challenging, and in late-stage disease unequivocal diagnostic assignment of the condition to any one of the recognized PCA entities can become impossible.[4,8] Monitoring disease activity is also notoriously difficult, particularly in conditions with minimal visible inflammation (e.g. pseudopelade of Brocq – see below). To make things worse, no fully satisfactory, evidence-based medicine (EBM) regimens are available for the treatment of defined scarring alopecias. Therefore, not only the pathogenesis, but also the effective management of PCA remain painfully under-investigated areas of dermatology. Given how cosmetically disfiguring and, therefore, psychologically devastating PCA can be, this is particularly lamentable.
This review aims to summarize available treatment options for PCA and to propose a hierarchy of treatments based on available evidence. The quality of evidence for each treatment will be displayed as follows: A, randomized controlled trial (RCT); B, study >20 participants; C, study <20 participants; D, series >5 cases; E, case report or expert opinion; with the highest grade of evidence being displayed for each treatment recommendation. These levels of evidence are based on those proposed by Lebwohl et al. However, caution is still required when interpreting these recommendations as the majority of studies only contain small numbers of patients, thereby limiting the conclusions that can be drawn. Patient numbers are therefore included in the text, where possible, to highlight this problem. Studies were identified from Medline searches, manual searches in journals, textbooks and review articles, and from personal experiences. Electronic keyword searches included a general search for 'cicatricial alopecia' as well as searches for each specific disease term (see below). Titles and abstracts were screened and, where necessary, full papers acquired.
Treatments have been allocated into recommended groups based on a broad appraisal of the efficacy, safety and familiarity of each agent. For example, familiar therapies with good side-effect profiles are generally chosen before more toxic or experimental treatments. Obviously if a particular therapy shows a clear therapeutic benefit (e.g. prolonged treatment-free remission) it may be rated more highly, particularly if the benefits appear to outweigh the risks. As with all areas of medicine an informed discussion between the clinician and patient is required before any treatment strategy is agreed.
The British Journal of Dermatology. 2008;159(1):1-22. © 2008 Blackwell Publishing