Epidemiology and clinical manifestations

Formerly believed to be very uncommon, vulvovaginal lichen planus is now either recognized much more often or has become more common. Lichen planus of any site occurs in about 1% of people, and approximately 57% of women with oral lichen planus exhibit vulvovaginal disease, which is often asymptomatic^1,2.

Vulvovaginal lichen planus occurs in several different morphologic forms and individual patients often present with several variants concomitantly (Table 15.1). These include erosive disease; white, reticulate lacy striae; sheets of white epithelium; and, on nonmucous membrane skin, red, or dusky red-brown papules.

Table 15.1 Usual Morphologic Variants of Vulvovaginal Lichen Planus

Most common on vulvovaginal skin is erosive lichen planus, which exhibits characteristic but nonspecific symptoms and signs. Patients generally report introital irritation, burning, superficial dyspareunia, and, sometimes, itching. About two-thirds of women with erosive genital lichen planus experience oral lichen planus usually associated with oral pain³. On physical examination, erosive lichen planus typically exhibits relatively well-demarcated vestibular erosions, with late disease manifested by scarring and resorption of normal landmarks (Figures 15.1–15.3). Many women also experience erosions of the labia minora, medial labia majora, and any area of the modified mucous membranes (Figure 15.4). Agglutination of the labia minora is common, as are adhesions which bury the clitoris. Erosive disease sometimes produces midline fusion of the vestibule, with resultant narrowing of the introitus (Figure 15.5). Rectal involvement is common (Figure 15.6).

Figure 15.1 This sharply demarcated erosion of the posterior fourchette with surrounding white epithelium is typical of erosive lichen planus.

Figure 15.2 Erosive lichen planus well localized to the vestibule, with surrounding, patchy, white epithelium, and narrowing of the introitus due to midline agglutination anteriorly.

Figure 15.3 Erosions and white striae (arrow) accompanied by generalized scarring and loss of labia minora, with the clitoris buried under the clitoral hood.

Figure 15.4 At times, lichen planus is more extensive, affecting all areas of the vulva and extending to hair-bearing skin.

Figure 15.5 Erosions, white papules, and marked narrowing of the introitus are present in the patient with lichen planus.

Figure 15.6 Perianal lichen planus is common, and is morphologically similar to vulvar lichen planus.

Erosive vulvar lichen planus is usually accompanied by vaginal and oral lichen planus, the “vulvovaginal–gingival syndrome.” Erosive vaginal lichen planus presents as superficial vaginal erosions or deep vaginal redness. Vaginal secretions are grossly and microscopically purulent (Figure 15.7). The yellowish or green discharge microscopically shows multiple white cells (mostly neutrophils), parabasal and basal cells (immature epithelial cells) shed from the base of erosions, and a marked decrease in lactobacilli, leading to an alkaline pH. Just as vulvar lichen planus results in scarring, synechiae of the vagina sometimes occur, occasionally resulting in complete closure of the vagina.

Figure 15.7 This wet mount of vaginal secretions of a patient with vaginal lichen planus shows large numbers of immature, parabasal cells, a remarkable number of white blood cells, and a lack of lactobacilli.

An examination of the mouth of a woman with erosive vulvovaginal lichen planus usually reveals white, lacy papules and striae and/or erosions on the posterior buccal mucosae (Figure 15.8). Often, women with erosive vulvovaginal lichen planus experience associated erosions and intense redness of the gingivae (Figure 15.9). The tongue is sometimes involved, with white, hyperkeratotic surface epithelium and/or erosions (Figure 15.10). Esophageal erosive lichen planus is becoming more recognized and can produce strictures that interfere with swallowing⁴.

Figure 15.8 Often, erosive vulvar lichen planus is accompanied by classic white, lacy striae of the buccal mucosae, sometimes accompanied by erosions.

Figure 15.9 Gingival lichen planus can be manifested by well-demarcated erosions as in this patient, or diffuse beefy red gingivae, or by white striae.

Figure 15.10 Women with erosive vulvar lichen planus sometimes experience concomitant lichen planus of the tongue, frequently manifested by diffuse white epithelium, often with irregular hyperkeratosis and erosions.

Although vulvar lichen planus is most often accompanied by vaginal and oral disease, some women exhibit disease in only one or two of these three sites.

Also, some patients experience involvement in additional areas, including the rectal mucosa and the esophagus. Like the vagina, esophageal adhesions and stenosis can occur. The extra-auditory canals and nasal mucosa are uncommonly affected. Occasionally, women with erosive vulvovaginal disease experience extragenital lichen planus, with dusky red papules on keratinized skin, destruction of nails, or scalp involvement producing scarring alopecia.

A second morphological presentation of vulvovaginal lichen planus is the classic, lacy, white epithelium (Figures 15.11 and 15.12). Although this classic mucosal lichen planus is much less common than erosive lichen planus, this form is pathognomonic for lichen planus. This manifestation is characterized by white striae, often forming fern-like or reticulate plaques. These distinctive plaques are frequently accompanied by vaginal lichen planus. Oral lichen planus occurs in this setting as well.

Figure 15.11 Although classic, well-formed white, lacy, reticulate striae are uncommon.

Figure 15.12 Typical white striae can occur on perianal skin as well.

Fairly often, mucosal vulvar lichen planus is characterized by a third morphology, that of uniformly white epithelium which often surrounds erosions (Figures 15.13 and 15.14). White lesions of lichen planus, whether fern-like or solid, are always located on mucous membrane or moist modified mucous membrane skin rather than on dry, keratinized skin. Women with white papules and plaques are most likely to experience itching.

Figure 15.13 Lichen planus can exhibit white, generalized epithelium that mimics lichen sclerosus.

Figure 15.14 These white plaques surrounding mucous membrane erosions are typical but not specific for lichen planus.

Yet another morphology of lichen planus occurs on dry, keratinized skin, presenting as dusky red, flat-topped, shiny papules (Figure 15.15). Extragenital lichen planus can occur almost anywhere, although facial involvement is extraordinarily uncommon. Only about 3–5% of women with erosive vulvovaginal lichen planus experience nonmucous membrane disease.

Figure 15.15 These erythematous, flat-topped papules of extragenital lichen planus generally do not accompany vulvar disease.

Diagnosis and differential diagnosis

The differential diagnosis of lichen planus depends upon the presenting morphology. Erosive lichen planus most closely resembles mucosal blistering diseases, because the fragile blisters on mucosal surfaces erode as they form, leaving nonspecific erosions (Table 15.2

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