Keywords

A 52-year-old female patient presented with an localized area of incomplete alopecia.

A physical examination revealed ill-defined patchy areas of incomplete alopecia (Fig. 29.1).

Fig. 29.1
figure 1

In ill-defined patchy areas of incomplete alopecia

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Dermoscopy showed localized ivory white structureless areas of alopecia with the absence of follicular openings. The remaining follicles showed perifollicular scaling and violaceous structureless areas (Fig. 29.2).

Fig. 29.2
figure 2

Dermoscopy shows localized ivory white structureless areas of alopecia with the absence of follicular openings. The remaining follicles showed perifollicular scaling and violaceous structureless areas

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Based on the case description, clinical and dermoscopic photographs, what is your diagnosis?

Differential Diagnoses

  1. 1.

    Alopecia areata.

  2. 2.

    Lichen planopilaris.

  3. 3.

    Discoid lupus erythematosus.

  4. 4.

    Dissecting cellulitis.

Diagnosis

Lichen planopilaris. 

Discussion

Lichen planopilaris (LPP) is a primary cicatricial alopecia caused by chronic lymphocytic inflammation around the upper portion of the hair follicle. The origin of LPP, and the other primary cicatricial alopecias, remains poorly understood, but they all have in common a targeted folliculocentric attack, which leads to irreversible follicular destruction and permanent hair loss [1].

LPP usually presents as irregular patchy hair loss, with loss of follicular ostia, a hallmark of all cicatricial alopecias. Less commonly the hair loss is diffuse rather than patchy. Perifollicular erythema and perifollicular scale are typically present at the periphery of active lesions. Cutaneous lichen planus may develop before, during, or after the onset of LPP . Oral and genital lesions may also occur. Many patients have a history of scalp scaling, often considered seborrheic dermatitis, for many years before the diagnosis of LPP. Active, untreated LPP is often intensely symptomatic with severe pruritus, pain, tenderness, and burning [2].

Diagnosis of LPP always requires clinicopathological correlation and cannot be made by the above clinical signs and symptoms alone. At least one four mm deep punch biopsy specimen down to subcutaneous fat is submitted for horizontal sectioning and hematoxylin-eosin staining. Compared with vertical sectioning where three–four follicles may be acquired, horizontal sectioning allows up to 30 follicles to be examined. The biopsy site is an active, symptomatic hair-bearing area with perifollicular erythema and perifollicular scale, located at the margin of a bare patch, with a positive anagen pull test result when possible [1, 2].

The most common trichoscopic features of classic lichen planopilaris include the absence of follicular openings, perifollicular scaling and white cicatricial areas. Other common trichoscopic findings are perifollicular erythema, milky-red areas, classic white and blue-grey dots [3,4,5]. Perifollicular erythema and white cicatricial areas are associated with disease severity [3].

Key Points

  • Lichen planopilaris usually presents as irregular patchy hair loss, with loss of follicular ostia

  • Diagnosis of lichen planopilaris always requires clinicopathological correlation and cannot be made by the clinical signs and symptoms alone