Topical Treatment for Scarring and Non-Scarring Alopecia: An Overview of the Current Evidence

Abstract

Alopecia is a clinical condition related to hair loss that can significantly affect both male and female adults' quality of life. Despite the high market demand, only few drugs are currently approved for alopecia treatment. Topical formulations still bring drawbacks, such as scalp irritation with frequent use, and low drug absorption to the site of action, which limits the efficacy. The most recent research points out that different formulation technology could circumvent the aforementioned flaws. Such technology includes incorporation of drugs in rigid or deformable nanoparticles, strategies involving physical, energetical and mechanical techniques, such as iontophoresis, sonophoresis, microneedling, and the use of solid effervescent granules to be hydrated at the moment of application in the scalp. In this paper, the progress of current research on topical formulations dedicated to the treatment of alopecia is reviewed and discussed.

Surgical Management of Scarring Alopecia

“…Alopecia is a clinical condition characterized by hair loss of hair-bearing aesthetic subunits and is divided into two main categories; scarring (also described as cicatricial) and non-scarring alopecia (Table 1) [3][4][5][6]. In non-scarring alopecia, the hair follicles remain intact and their regrowth abilities are preserved [3][4][5][6]. However, permanent hair loss may occur in the late stages of non-scarring alopecia, called "biphasic alopecia" [7].…”

“…Androgenic alopecia is the most common type of non-scarring hair loss that affects nearly half of men. It is characterized by temporal recession and vertex balding in men, diffuse hair thinning and intact frontal hairline in women [4][5][6]8]. Cicatricial alopecia presents a heterogeneous group of disorders, which are characterized by destruction and fibrous tissue replacing of the hair follicles, resulting in scarring and permanent hair loss.…”

“…Cicatricial alopecia is classified into two categories depending on the target of the pathological process; primary cicatricial alopecia (PCA) and secondary cicatricial alopecia (SCA) (Table 1). In PCA, the hair follicle is the primary and sole target of a progressive inflammatory process in various skin or systemic diseases [4,6,7,9,10]. In SCA, non-specific and generalized disruption of the skin and skin appendages results in fibrotic scarring of the skin and permanent loss of hair follicles due to underlying disease or an external agent [3,6,7,10,11].…”

Tectoridin Stimulates the Activity of Human Dermal Papilla Cells and Promotes Hair Shaft Elongation in Mouse Vibrissae Hair Follicle Culture

“…Non-scarring alopecia refers to hair loss due to the hair cycle being disrupted, as in cases of alopecia areata, telogen effluvium and androgenic alopecia. In non-scarring alopecia, hair follicles are preserved, and which can be reactivated for hair regrowth [10]. During embryonic and adult stages, the Wnt/β-catenin signaling plays an important role in hair morphogenesis and cycling [3,11].…”

Clinicopathological Features of Alopecia With an Emphasis on Etiology and Histopathological Characteristics of Scarring Alopecia

“…Scarring alopecia is further classified on the basis of the predominant inflammatory cell type into lymphocytic that includes discoid lupus erythematosus (DLE), lichen planopilaris (LPP) and pseudopelade of Brocq (PB); neutrophilic that includes folliculitis decalvans (FD), dissecting cellulitis (CD)/folliculitis (perifolliculitis capitis abscedens et suffodiens); and mixed that includes acne keloidalis nuchae (AKN) and erosive pustular dermatosis. Alternatively, non-cicatricial alopecia results due to an alteration in the capillary cycle, which leads to temporary or partial destruction of hair follicles, so hair shedding is followed by hair regrowth [ 5 ]. Non-scarring alopecia is further classified into alopecia areata, trichotillomania, traction alopecia, telogen effluvium and androgenic alopecia.…”