21 - pseudopelade ( foot prints in snow alopecia )

q:which is the variant of alopecia that shows "foot prints in snow" pattern ?

a. pseudopelade
b. trichotillomania
c. alopecia areata
d. all the above

answer : a . pseudopelade

Brocq used the term pseudopelade to describe a peculiar form of scarring alopecia resembling alopecia areata. (Pelade is the French term for alopecia areata.) This clinical entity is not a specific disease but a pattern of scarring alopecia, and the term pseudopelade of Brocq eventually should be abandoned. An additional source of confusion is the modern use of the term pseudopelade to describe a different form of scarring alopecia (ie, central, centrifugal, scarring alopecia [CCSA]).

Pseudopelade of Brocq is an end stage or clinical variant of various other forms of scarring alopecia and a diagnosis of exclusion. The same pattern of hair loss can be seen in burnt out (ie, no clinical or histologic evidence of inflammation) discoid lupus erythematosus (DLE), lichen planopilaris (LLP), and other forms of scarring alopecia. If a definitive diagnosis of DLE, LPP, or another condition can be made based on clinical, histologic, or immunofluorescent features, then the term pseudopelade of Brocq cannot be used. A primary form of traditional pseudopelade may exist, but this has yet to be established with certainty.

Pseudopelade of Brocq is a very uncommon pattern of alopecia.

Whites usually are affected more often.

Either sex can be affected.

Adults usually are affected more often, although the condition has been reported in children.

The typical patient is surprised to discover discrete asymptomatic areas of scalp hair loss . In many patients, the disease is slowly progressive; ie, new areas of alopecia develop over a period of months to years. However, the condition often worsens in spurts, with periods of activity followed by dormant periods. This is distinctly different from the slow but steady disease progression seen in several other forms of scarring alopecia. Disease progression in pseudopelade eventually ends spontaneously.

Lesions of pseudopelade are randomly distributed, irregularly shaped, and often clustered in patches on the scalp. Cases with exclusive crown or vertex involvement actually may represent examples of burnt-out, central, centrifugal, cicatricial (scarring) alopecia (CCCA). The individual lesion is hypopigmented (porcelain white is the classic description) and slightly depressed (atrophic). Lesions often are shaped irregularly, as opposed to the round or oval patches usually seen in alopecia areata and most cases of CCSA.

The classic description of "footprints in the snow" refers to dermal atrophy causing a slight depression below the surrounding normal scalp. In fact, many cases of pseudopelade do not demonstrate atrophy. Usually, only mild erythema and slight perifollicular scaling are present, and, often, no clinical evidence of inflammation is present. In fact, some authors would argue than any inflammation excludes traditional pseudopelade from the clinical differential diagnosis. Typical of many forms of scarring alopecia, a few isolated hairs may remain within an otherwise smooth, shiny, denuded patch. Include the nails and oral mucosa as well as the skin in physical examination to exclude evidence of other forms of scarring alopecia. Pseudopelade of Brocq is a diagnosis of exclusion.

Pseudopelade of Brocq is felt to be the end stage of several different forms of scarring alopecia, especially lichen planopilaris and chronic cutaneous lupus erythematosus. Therefore, the cause of pseudopelade of Brocq is linked to the etiology of the underlying skin disease.

Differentials:

Aplasia Cutis Congenita
Lupus Erythematosus, Discoid

Central, centrifugal, scarring alopecia
Follicular degeneration syndrome
Lichen planopilaris
Temporal triangular alopecia

Lab Studies

• No laboratory test has been found useful in establishing the diagnosis of pseudopelade of Brocq. If the history or physical examination suggests evidence of lupus erythematosus, antinuclear antibody testing would be appropriate.

Procedures

• Scalp biopsy is required for determining both diagnosis and prognosis.

·

• Ideally, the biopsy specimen is at least 4 mm in diameter and is sectioned transversely (horizontal to scalp surface).
• At the very least, discovering that follicles have been replaced by connective tissue will confirm the diagnosis of permanent scarring alopecia.

Histologic Findings

The histopathologic findings of traditional pseudopelade have yet to be clearly defined. The criteria established by Pinkus, based on his experience and on the writings of several other authors, are not correlated in any way with clinical features. Thus, pseudopelade as described by Pinkus is a histologic and not a clinical entity. In most cases of traditional pseudopelade, the active lesion is elusive, and the typical histologic findings are those of a burnt-out scarring alopecia. The histologic findings of pseudopelade of the crown more recently described apply to CCCA and not pseudopelade of Brocq. A prospective study of pseudopelade of Brocq with sound clinical correlation has yet to be performed. In most cases, if an active lesion is sampled, the histologic findings are those of the primary process, eg, lichen planopilaris.

Treatment:

When lesions of pseudopelade of Brocq are burnt out, treatment is neither necessary nor possible. Unfortunately, the condition can reactivate episodically and unpredictably. If active inflammation is present, consider an alternative diagnosis, and potent topical corticosteroids, such as fluocinonide or clobetasol, can be tried.