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Scarring Alopecia

Background

A systematic approach to the evaluation of alopecia allows for more effective management. Below is a step-by-step approach that can be used in scarring alopecia:

Initial classification of alopecia type

Applying scarring alopecia terminology based on clinical features

Using histology findings to further support/define the diagnosis

Providing an overall evaluation/diagnosis with treatment options

Initial classification

The initial determination of alopecia type usually begins with the establishment of alopecia as either a scarring (cicatricial) alopecia or nonscarring alopecia. Nonscarring alopecias tend to have preserved follicular ostia. No clinically visible inflammation is noted in most presentations, although histologic inflammation may be present. The most common nonscarring alopecias include alopecia areata and telogen effluvium.

Scarring alopecias have loss of follicular ostia, or atrophy. Clinical inflammation is frequently, but not always, present. Histologic inflammation may be present. Ultimately, histologic confirmation is the best method to confirm the presence of a fibrosing/scarring process with loss of hair follicles.

Many alopecia types are biphasic. For example, androgenetic alopecia eventually results in loss of ostia and thus may appear like a scarring alopecia. This article focuses on the alopecia types that are believed to be due to an inflammatory response with rapid secondary scarring if not controlled.

Scarring alopecia terminology based on clinical features

Once the patient is determined to have scarring alopecia, establishing and clarifying the diagnostic options and terminology is important to assist in confirming the diagnosis, initiating treatment, and suggesting a prognosis. Several manuscripts have examined and attempted to clarify the literature findings,
as summarized below.

Also important to note is that examination alone cannot be the final step; the literature is filled with examples of misdiagnosis and diagnostic mimics in alopecia.
This includes patients presenting with nonscarring, noninflammatory alopecia that is later found to be scarring and inflammatory.
Even amongst the scarring alopecia presentation, it is sometimes debated as to the role of immune alteration versus pure external factors that cause the scarring alopecia. Much of the confusion is often based in the similarities of clinical presentation, which emphasizes again the importance of not basing diagnosis purely on clinical examination findings alone.

Diagnoses in which lymphocytes predominate are as follows:

Lichen planopilaris

The diagnosis of lichen planopilaris (LPP) is confirmed by a combination of clinical and histologic features. The following subtypes are recognized
:

Frontal fibrosing alopecia (FFA): This is a potential clinical variant of lichen planopilaris, with similar histologic features. Frontal fibrosing alopecia has been associated with the postmenopausal state (ie, postmenopausal frontal fibrosing alopecia), although not all patients with this diagnosis are postmenopausal. Note the image below.

End-stage scarring alopecia (ESSA) with prior hist

End-stage scarring alopecia (ESSA) with prior history of itching and burning, along with a receding hairline. Started as the lichen planopilaris variant, frontal fibrosing alopecia. Used with permission, rights retained, courtesy of Rashid M. Rashid, MD, PhD, Morzak Research Collaborative.

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Fibrosing alopecia in pattern distribution (FAPD): This also is a potential clinical variant of lichen planopilaris, with similar histologic features. Additionally, fibrosing alopecia in pattern distribution has some histologic/clinical overlap with androgenetic alopecia. Fibrosing alopecia in pattern distribution may also be an overlap of lichen planopilaris with androgenetic alopecia.

Graham-Little syndrome: This entity is also a possible overlapping condition, with features of lichen planopilaris and other alopecia types.

Central centrifugal cicatricial alopecia (CCCA)

CCCA is a diagnostic category adopted by the North American Hair Research Society to encompass terms such as hot comb alopecia, follicular degeneration syndrome, pseudopelade in African Americans, and central elliptical pseudopelade in whites.
Despite the many attempts to clarify and unify the terminology of central CCCA patterns of scarring alopecia, CCCA is not clearly a diagnostic entity in and of itself.

Pseudopelade

Pseudopelade is a term used to describe a clinically noninflammatory patchy alopecia. The most common condition to produce this appearance is lichen planopilaris. The term “idiopathic pseudopelade” refers to a distinct fibrosing alopecia characterized by a thin dermis, with dense eosinophilic dermal collagen and thick recoiled elastic fibers. The fibrous tracts are broad and may contain granulomas, but the surrounding elastic sheath is preserved.

Traction alopecia

As the name implies, traction alopecia is alopecia secondary to physical traction. Variant presentations exist with terminology that is optional for differentiating purposes. This includes alopecia linearis frontalis (ALF), more commonly known as marginal alopecia, and chignon alopecia, which is when a tight hair bun causes the traction changes.

Secondary systemic scarring alopecia

Secondary systemic scarring alopecia is a term used when the alopecia is a feature of a systemic disease (eg, scleroderma, discoid lupus erythematosus). Discoid lupus erythematosus is often a cause of alopecia. In the classic lupus classifications scheme, discoid lupus erythematosus is one of the chronic cutaneous lupus types (along with tumid lupus and lupus panniculitis).

Trichotillomania

Trichotillomania is a nonscarring psychiatric alopecia that can have a scarring clinical presentation. Trichotillosis is an alternative term that some physicians believe is more acceptable to patients.

Chemotherapy alopecia

Chemotherapy alopecia is often thought of as nonscarring alopecia; however, reports of permanent alopecia suggest that hair stem cells can be permanently destroyed. Note the image below.

Alopecia due to primary cutaneous follicular cente

Alopecia due to primary cutaneous follicular center cell lymphoma. Used with permission, rights retained, courtesy of Rashid M. Rashid, MD, PhD, Morzak Research Collaborative.

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Alopecia mucinosa

Follicular mucinosis can exist by itself or can be a manifestation of mycosis fungoides.

Keratosis pilaris atrophicans

Keratosis pilaris atrophicans involves a spectrum of conditions that resemble keratosis pilaris, but result in hair loss.

Diagnoses in which neutrophils predominate are as follows:

Folliculitis decalvans: Folliculitis decalvans presents with recurrent crops of follicular pustules that result in permanent epilation. Staphylococci are often cultured from pustules, but this condition does not respond the standard antibiotic regimens. The best results are obtained by long-term use of topical corticosteroids together with an oral tetracycline.

Perifolliculitis capitis abscedens et suffodiens: Other terms used for perifolliculitis capitis abscedens et suffodiens include dissecting cellulitis and Hoffman disease. It resembles hidradenitis suppurativa and the 2 often occur together.

Tufted hair folliculitis: Tufted hair folliculitis often contains Staphylococcus aureus, but it is unclear if a preexisting abnormality predisposes to staphylococcal infection. Clinically, 5-20 hairs emerge from a common dilated follicular orifice, producing a clinical resemblance to doll hair. This is often seen as a reactive pattern present in multiple types of scarring alopecia and even as a reaction to medications.

Diagnoses in which a mix of cell types predominate are as follows:

Acne keloidalis: Others terms used for this condition include acne keloidalis nuchae, dermatitis papillaris capillitii, sycosis nuchae, and folliculitis keloidalis. Patients present with pustules, alopecia, and hypertrophic scarring on the posterior neck. Many plasma cells are typically present in the infiltrate.

Acne necrotica: Acne necrotica is sometimes also called folliculitis necrotica. This condition is rare and exists in 2 variants. The first is acne necrotica varioliformis, which is a distinctive necrotizing disorder of the hair follicle that heals with varioliform scars. The second is acne necrotica miliaris, which is a nonscarring folliculitis.

Erosive pustular dermatosis of the scalp: This condition often follows surgery or other trauma. It presents with an expanding patch of crusts and pustules.
It has been reported to respond to potent topical corticosteroids, tacrolimus, and light therapy.

Diagnoses for which the least evidence-based characterization is available are as follows:

Pressure alopecia: Pressure alopecia is due to constant pressure to the region. Often described as a nonscarring reversible alopecia, it has also been reported to result in permanent scarring. This may be more accurately termed externally traumatic alopecia or iatrogenic alopecia.
As in chemotherapy alopecia, the rapidly growing hair follicle and hair cell source (bulge and associated regions) may be especially susceptible to antimetabolic insult, such as lack of blood flow.

Lipedematous alopecia: Lipedematous alopecia is a rare condition with unknown scarring potential. It is also referred to as lipedematous scalp.

Senescent alopecia: Senescent alopecia is also known as senile alopecia, a diffuse thinning due to decreased terminal hairs but without increased miniaturization.
It is thought to affect people aged 40-50 years or older with no family history or evidence of pattern balding. Senescent alopecia is not a primary diagnosis in all clinics and often is debated as a diagnosis as actually being late-onset androgenetic alopecia.

Keratosis follicularis atrophicans

Possible variants include keratosis pilaris decalvans, an X-linked and sporadic condition, and folliculitis spinulosa decalvans, which is autosomal dominant.

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