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LOCALIZED AND SCARRING ALOPECIAS

As briefly discussed earlier, the presence of follicular scarring is a critical sign diagnostically, as well as prognostically for potential hair regrowth. This helps to differentiate between various forms of localized alopecia; for example, in the commonest form of localized alopecia, AA (discussed earlier), the follicles are quite obviously present.

    A scarred follicle implies permanent damage without prospect of regrowth, whereas an intact follicle can potentially regrow hair; sometimes this happens in alopecia after many years. Note, however, that in some longstanding but not primarily scarring disorders, the follicles gradually shrink, and regrowth becomes impossible.

    An important issue in scarring alopecias is the presence and pattern of inflammation that leads to the scarring. While causes such as burns or trauma are self-evident, most patients presenting to a dermatologist will have an inflammatory process (Table 28.4). Skin biopsy may help to evaluate the cause but should not be taken from an area of established scarring; rather, it should be from the margin of the area and ideally (if clinically apparent) from an area of intact hairs with perifollicular erythema. Discoid lupus erythematosus is in the differential diagnosis of many scarring alopecias, and can be diagnosed by a positive direct immunofluorescence test (Ch.16) on the biopsy, so it is usual for an appropriate sample to be submitted for pathologic examination when biopsying scarring alopecias.

Fig. 28.23 Alopecia due to chronic rubbing in a patient with lifelong atopic dermatitis.

Fig. 28.24 Trichotillomania. Sections of hair are at various lengths. The use of scissors was suspected in this older woman, who flatly denied any knowledge of how her hair became this way.

Fig. 28.25 Trichotillomania. Note the preservation of the hairline.

Fig. 28.26 Trichotillomania. Many cases of trichotillomania are limited in size (e.g. 1–2 cm in diameter), like the case illustrated here. The key clinical finding is multiple hairs varying from 1 to 5 mm in length. The patient may or may not admit to repeated scratching.

Trichotillomania

Etiology and pathogenesis

Hair loss may occur due to manipulation of the hair by the patient, by rubbing, twirling, twisting, or simply pulling (Figs 28.23 – 28.26). Trichotillomania is a form of self-inflicted hair damage in which there is an underlying psychologic cause. Young or adolescent girls are most commonly affected. School difficulties, sibling rivalries, dysfunctional mother– daughter relationships, a traumatic move, etc. may be precipitating problems.

Clinical

One or more patches of hair loss may occur, sometimes so extensive as to suggest a diffuse process. It is characteristic that the remaining short hairs have varying lengths (due to breakage at different points in the hair shaft and over a period of time); it is very unusual to have areas of complete alopecia. The hairline is often maintained, but the eyebrows and eyelashes may be pulled out (Figs 28.25 and 28.26).

Fig. 28.27 Tinea capitis due to Trichophyton tonsurans: ‘black dot’ alopecia. (Courtesy of Dr. E. M. Higgins.)

Fig. 28.28 Traction alopecia. A young black girl with alopecia at the margin of tight braids: the classic appearance.

Differential diagnosis

The differential is that of patchy, non-inflamed hair loss (as for AA, Table 28.3). Indeed, AA is commonly diagnosed but can easily be excluded, as the hairs are broken, not absent, and short hairs are normally attached to the hair root (by contrast, the short exclamation mark hairs of AA fall out with minimal traction). The nails may be dystrophic from onychophagia, but pits (as in AA) are not seen.

Treatment

Both the child and the parents should be involved in a tactful but open discussion about the suspected diagnosis. Referral for counseling and behavior therapy should be considered. Behavior modification may focus on decreasing trigger factors and promoting substitute behaviors. Support groups may help. Hyponosis has been used. Medical therapy as an adjunctive measure has been employed, for example clomipramine.

Tinea capitis

A discrete patch of alopecia in the scalp of a child where the skin is covered with scale, pustules, and/or black dots is typical of tinea capitis (Fig. 28.27; see also Ch. 26).

Traction alopecia

Hair loss at sites of chronic traction (e.g. tight ponytails, braids, or curlers) is called traction alopecia (Figs 28.28 and 28.29). Young black girls are most often affected. Inflammation is usually not seen. Elimination of the traction is usually curative in early cases. Longstanding alopecia is usually permanent.

Fig. 28.29 Traction alopecia. Partial or near-complete alopecia in this area of the scalp in a black girl or woman is almost always the result of traction alopecia. It often takes a little time to convince the patient of the true cause. Unfortunately, hair regrowth will usually not occur if longstanding.

Fig. 28.30 Temporal triangular alopecia.

Fig. 28.31 Temporal triangular alopecia. Note the nearly identical appearance between the child seen here and the child in Figure 28.30, children from two different continents.

Temporal triangular alopecia

Oval or triangular areas of alopecia in the temporal areas of the scalp in a child are characteristic (Figs 28.30 and 28.31). Onset is usually between 2 and 6 years of age. Bilateral lesions may occur. The ‘bald spot' actually contains a normal number of hairs, but they are vellus hairs instead of the usual terminal hairs. The scalp is normal. The prevalence is 0.11%, based on 6200 individuals seen in one study, of whom seven were affected. Usually, no treatment is needed other than reassurance that this is not very early male pattern baldness (which doesn't occur before puberty); however, complete surgical excision or hair transplantation may be done.

Secondary syphilis

In the second stage of syphilis, loss of hair occurs in patches, giving a moth-eaten appearance (Fig. 28.32; see Ch. 24).

Fig. 28.32‘Moth-eaten’ alopecia of secondary syphilis. (Courtesy of Michael O. Murphy, M.D.)

Fig. 28.33 Central centrifugal cicatricial alopecia.

Central centrifugal cicatricial alopecia (cicatricial vertex alopecia)

Central centrifugal cicatricial alopecia, previously known as follicular degeneration syndrome, is a cause of hair loss primarily seen in the adult dark-skinned woman. For years, it was probably called ‘hot comb alopecia'. Its cause is unknown. A young to middle-aged black woman with hair loss in the centrofrontal region of the scalp is characteristic (Fig.28.33). Hair loss may be minimal to near-complete. In longstanding disease, the follicular orifices are lost. The crown is always involved, and there is usually sparing at the periphery. Men may also be affected. Diagnosis is confirmed by punch biopsy sectioned transversely. No effective therapy is available. Any traumatic hair care practices should be avoided, although their etiologic involvement is debatable.

Fig. 28.34 Pustular folliculitis. Staphylococcus aureus was cultured in this case. Oral antibiotics cleared the eruption.

Folliculitis decalvans and related disorders

There are a group of terms that can be very confusing and difficult to differentiate from the published literature. Some may overlap; some probably share the same bacterial etiology but are morphologically different; and some distinctive morphologies respond to varied treatment approaches, thus suggesting that they may represent a ‘final common pathway'. One difficulty in evaluating such disorders is that staphylococcal infection may complicate an inflammatory cause of folliculitis, while, conversely, preceding staphylococcal infection may have been eradicated by the inflammatory response but a sterile pustule may still be present as a result of ongoing inflammation secondary to follicular destruction. For this reason, swabs from several pustules over a period of time may give a more accurate feel for the primary problem.

The terms that require elaboration in this section are:

Pustular folliculitis

This is sometimes also termed bacterial folliculitis, but this may mislead: scalp pustules may indeed culture bacteria (usually Staphylococcus aureus , Fig.28.34) but may be due to fungi or virus infection, or may be sterile (in which case, they might represent a simple irritant problem, or may be the manifestation of a significant inflammatory response to follicular destruction). If Staph. aureus is cultured, then it may represent a primary bacterial infection or a secondary infection of another process. In turn, if it is a primary infection, then it may represent a simple folliculitis that will be easily cleared with a course of oral antibiotics, it may be a recurrent problem but still with a simple follicular morphology, or it may lead to the appearances of the other nomenclature discussed here.

Tufted folliculitis

Many would view this as a purely descriptive term, in which tufts of multiple hairs emerge from a single orifice (polytrichia) surrounded by scarring (the doll's head appearance, Fig.28.35). However, others (while accepting that tufted follicles may occur in several circumstances) believe that tufted folliculitis is a specifically staphylococcal infection and the same as folliculitis decalvans.

Folliculitis decalvans

This term has been used rather loosely to describe any severe scarring and pustular alopecia process. Some now use the term to mean a specifically staphylococcal infection, while others view it as a subset of central centrifugal cicatricial alopecia (and the ‘follicular degeneration syndrome' as another, usually separate, subset of central centrifugal cicatricial alopecia).

Fig. 28.35 Tufted folliculitis. Note the inflamed skin and multiple hairs emerging from a single orifice.

Treatment

Treatment for this group of conditions obviously depends on whether or not Staph. aureus is the cause, and also the severity if it is, as follows.

Dissecting cellulitis of the scalp

Etiology and pathogenesis

Dissecting cellulitis (also known as perifolliculitis capitis abscedens et suffodiens) is a chronic, inflammatory condition of the scalp that may occur in conjunction with other diseases of the follicular occlusion triad (acne conglobata and hidradenitis suppurativa). It presumably has an inflammatory etiology, although staphylococcal infection may occur, and it can be difficult to exclude this as a primary cause. Like central centrifugal cicatricial alopecia, it occurs mainly in African Americans, although the majority are young adult men.

Clinical

Inflammatory nodules, sinus tracts, chronic drainage, crusting alopecia, and scarring occur (Fig.28.36). Early in the course, inflammatory nodules and pustules are seen. Later, hypertrophic scars and keloids develop. The scarring may be plate-like or stellate. Tufts of hairs may be seen. The patient will often complain of pain, tenderness, and drainage (Fig.28.37).

Differential diagnosis of localized, inflamed alopecia

In the early stages, other scarring alopecias may need to be considered, especially the more inflammatory end of the spectrum of folliculitis decalvans or central centrifugal cicatricial alopecia. This can be a particular diagnostic problem when dissecting cellulitis occurs without other diseases of the follicular occlusion triad. Bacterial infection should, of course, be excluded. Usually, the depth of the inflammation in the scalp (clinically and histologically) and the development of sinuses in established disease distinguish dissecting cellulitis from folliculitis decalvans (in which the upper part of the follicle is damaged but there is no deep abscess formation).

Fig. 28.36 Dissecting cellulitis of the scalp. Inflammatory nodules, sinus tracts, chronic drainage, and sclerosing alopecia occur in this disease, also known as perifolliculitis capitis abscedens et suffodiens. Tufts of hair may emanate from a single opening.

Fig. 28.37 Dissecting cellulitis of the scalp. Hypertrophic scarring and keloid formation has developed. Note the solitary pustule. A bacterial culture should be taken.

Treatment

Antibiotics, either antistaphylococcal (as for folliculitis decalvans) or antiinflammatory (as for acne), may give control. Isotretinoin can also be effective, again making a link with acne. Either of these approaches may need to be administered as repeated or long-term treatment. Occasionally, marsupialization of the sinus tracks or incision and drainage of abscesses may be done; secondary infection may require other antibiotic choices.

    Once the patient is free of tenderness, inflammation, and pustules, then the scarring may be addressed. Intralesional triamcinolone each month may help reduce the scarring. In patients not responding to more conservative therapies, and who don't mind permanent loss of hair, laser-assisted epilation should be considered.

Discoid lupus erythematosus

Discoid lupus erythematosus (DLE) (Fig.28.38; see also Ch.13) is one of the commoner causes of scarring alopecia. An appropriate biopsy (see earlier) will help to establish the diagnosis.

Fig. 28.38 Lupus erythematosus of the scalp. Scarring alopecia with erythema and scaling.

Fig. 28.39 Frontal fibrosing alopecia. Note the receding frontal hairline in an older woman.

Lichen planopilaris

Follicular accentuation of lichen planus, also known as lichen planopilaris, may affect the scalp and cause localized alopecia (see Ch. 8, Fig. 8.7). The important differential diagnosis is DLE.

Frontal fibrosing alopecia

This disorder occurs in women, usually middle-aged, causing a gradual recession of the frontal scalp margin (Fig.28.39). It has been suggested that it may be a variant of lichen planus, but no clinically apparent inflammation is present. The main differential in postmenopausal women is a receding hairline as part of female pattern androgenetic alopecia.

Pseudopelade

Etiology and pathogenesis

Pseudopelade has been viewed as an idiopathic cause of scarring alopecia, although this may not always be correct; as discussed here, it may be the end result of several conditions. Nevertheless, it is useful as a description of a particular morphology, and the term is retained here. Most patients are women.

Clinical

Round to oval, non-inflamed, white, alopecic areas of the scalp, like footprints in the snow, are characteristic (Fig.28.40). No crust, scale, or follicular hyperkeratosis occurs. There may be perifollicular erythema in early and moderate atrophy in late stages. The course is chronic, with slow progression.

Fig. 28.40 (a,b) Pseudopelade. Complete hair loss is seen in a pattern likened to footprints in the snow.

Fig. 28.41 Aplasia cutis congenita.

Differential diagnosis

A biopsy is necessary to establish the diagnosis. The key differential is cutaneous lupus erythematosus or lichen planopilaris. Indeed, lesions with an identical appearance can occur in patients with lupus erythematosus (see Fig. 13.9b), and some cases of pseudopelade are probably ‘burned out' lupus or lichen planopilaris.

Treatment

If signs of either lichen planus or lupus are seen, appropriate therapy should be considered. In cases where one is left with the diagnosis of pseudopelade, and if progression is noted, hydroxychloroquine may be tried. In the case of old, stable, ‘burned out' disease, hair transplant or scalp reduction may be considered.

PRACTICE POINTS

Aplasia cutis congenita

This congenital disorder may occur at various body sites and may or may not be inherited, associated with other skin findings, associated with other (especially ectodermal) manifestation, or occur as part of a malformation syndrome. However, much the commonest pattern is a completely bald spot on the scalp in an otherwise normal newborn (Fig.28.41; see also Ch.19, Fig.19.29). Obstetric trauma is often erroneously blamed, especially if the area has the eroded appearance that may precede the scarring process.

Fig. 28.42 Alopecia neoplastica, in this case from breast cancer.

Erosive pustular dermatosis of the scalp

This condition typically affects fragile skin of elderly scalps, presenting as sheeted crusting. It is sterile, but primary bacterial infection and low-grade staphylococcal infection of granulation tissue need to be excluded. Temporal arteritis is usually more acute and painful, and slow-healing herpes zoster is unilateral, but either may at times be in the differential diagnosis. Biopsy may be needed to exclude a neoplasm.

Alopecia neoplastica

Infiltration of the scalp by metastatic disease may cause hair loss (Figs 28.42 and 33.46a).

White/Cox: Diseases of the Skin, 2ed.(c) 2006, Elsevier Inc. All rights reserved.