O.V. Parygina 1,2, I.O. Smirnova1–3, M.V. Oganesyan 1, Y.G. Petunova1,2,
N.V. Shin1, A.O. Zhelonkina1, A.R. Zhelonkin 1
1St. Petersburg State University, St. Petersburg, Russian Federation
2City Dermatovenerological Dispensary, St. Petersburg, Russian Federation
3I.I. Mechnikov North-Western State Medical University, St. Petersburg, Russian Federation
Lichenoid vulvar dermatoses are a heterogeneous group of diseases characterized by a number of overlapping signs and/or morphological features. Clinical similarity is accounted for by the appearance of small discrete papules with closely adjacent superficial squamae. The prototype of lichenoid dermatoses is lichen ruber planus. Histologically, lichenoid pattern is characterized by basal epithelial cell damage and a band-like infiltrate in the upper dermis. The International Society on Vulvovaginal Diseases categorizes lichen ruber planus and early lichen sclerosus as dermatoses with this histological pattern. Some authors also classify plasma cell (Zoon) vulvitis as lichenoid vulvar dermatoses. The cause of diagnostic errors lies in the similarity of the clinical and histological presentations of lichenoid vulvar dermatoses. Dermatoscopy should be considered as an additional diagnostic test. Only few studies address the key dermatoscopic signs of vulvar dermatoses. Histological study is important for the differential diagnosis. However, at some stages of disease evolution, vulvar dermatoses can have an overlapping histological pattern. This paper summarizes t he data on the clinical, histological, and dermatoscopic presentation of the most common lichenoid vulvar dermatoses, i.e., lichen planus, lichen sclerosus, lichen simplex chronicus, and plasma cell vulvitis.
Keywords: lichenoid dermatoses, vulvar dermatoses, lichen sclerosus, lichen planus, lichen simplex chronicus, plasma cell vulvitis, Zoon vulvitis, dermoscopy.
For citation: Parygina O.V., Smirnova I.O., Oganesyan M.V. et al. Lichenoid vulvar dermatoses: clinical presentation, morphology, and dermatoscopic signs. Russian Medical Inquiry. 2020;4(10):617–624. DOI: 10.32364/2587-6821-2020-4-10-617-624.
Lichenoid vulvar dermatoses are a heterogeneous group of diseases with a number of overlapping signs and/or morphological features .
Clinical presentation of lichenoid dermatoses is characterized by the appearance of papules with closely adjacent superficial squamae (the name “lichenoid dermatoses” comes from the Latin “lichen” meaning the symbiotic association of fungi and microscopic green seaweed) . The prototype of lichenoid dermatoses is lichen planus (LP). Lichenoid dermatoses also include lichenoid rash, lichenoid contact dermatitis, graft-versus-host disease, lichen sclerosus, atrophic lichen planus, and lichen simplex chronicus .
Histologically, lichenoid inflammatory pattern is characterized by basal epithelial cell damage and band-like infiltrate in the upper dermis . The International Society for the Study of Vulvovaginal Disease (ISSVD) attributes LP and early vulvar lichen sclerosus and atrophic lichen planus to the dermatoses with this histological pattern . Some authors also recommend classifying plasma cell (Zoon’s) vulvitis (which is clinically similar to erosive vulvar LRP) as lichenoid vulvar dermatosis .
The cause of diagnostic errors lies in the similarity of the clinical and histological presentations of lichenoid vulvar dermatoses. In the last decade, dermatoscopy has gained popularity for the diagnosis of inflammatory dermatoses [5, 6]. Despite only few studies, vulvar dermatoses are characterized by specific dermatoscopic signs which can be considered as additional diagnostic criteria [7–9].
The aim of this review article was to systematize the most typical clinical, morphological, and dermatoscopic signs of lichenoid vulvar dermatoses required for the correct diagnosis (see Table 1).
LP ranks second among chronic non-infectious vulvar dermatoses . This disease is commonly diagnosed in women aged 40-70 years but occurs in younger women as well [11, 12]. There are three variants of vulvar LP (VLP), i.e., typical (papular), erosive (the most common VLP), and hypertrophic .
Typical VLP is characterized by the appearance of flat polygonal livid papules at sites with keratinized or partially keratinized epithelium (labia majora and labia minora, pubic area) . The appearance of rash is accompanied by itching and pain. Subjective symptoms are sometimes lacking . Skin rash may be either single or multiple, fine white lines are occasionally seen on the top of papular rash (Wickham striae). These lesions may be annular in shape . Papules disappear without a trace, scarring is not typical for this variant. Vulvar lesions may be associated with oral mucosa and skin involvement. Vulva is affected in 25-57% of women with oral mucosal rash .
Hypertrophic VLP is the most uncommon variant. It manifests as confluent hypertrophic papules with hyperkeratosis which appear on edematous, erythematous (flesh-colored) skin [13, 16]. In some women, vulvar disease is accompanied by desquamative vaginitis with abundant vaginal discharge  which may result in vulvar and vaginal scarring .
Erosive VLP is the common variant. Erosions appearing around the vestibule of the vagina are characterized by well-defined borders, deep-red color, and smooth lucid surface [18, 19]. In a half of women, other mucosae and skin remain intact . In the rest of women, oral mucosa is affected more often compared to skin (mucosal LP). Pain, burning, bleeding after sexual intercourse, and dysuria rather than itching are a major concern for these women .
This rash resolves but leaves the area of atrophy and scarring which may cause the resorption of the labia minora, sealing of the clitoral hood, adhesions of the labia majora, vaginal opening stenosis, and vaginal strictures (see Fig. 1) .
Lichen sclerosus and atrophic lichen planus (lichen sclerosus et atrophicus) is the most common chronic non-infectious dermatosis affecting vulva . This disease mostly occurs in menopausal women (about 50% of cases) . However, this dermatosis may develop in the puberty (9%) and women of reproductive age (41%). Clinically, small (sized 3-6 mm) well-defined flat white shiny (confetti-like) papules emerge [23, 24]. These lesions may be isolated but are usually confluent to form dense milky-white plaques. As sclerosis and atrophy progress, vulvar mucosa becomes thin (cellophane-like), whitish, and wrinkly. Scratching results in erosions, ecchymosis, and cracked skin . Vulvar involvement is associated with the involvement of the perianal area (60% of cases) looking like a figure 8 or keyhole [23, 26].
Impaired vulvar architectonics is typical of this condition, i.e., adhesions between the clitoris and its hood (sometimes with pseudocyst formation), synechiae between the labia minora and labia majora, vaginal opening stenosis, anal stricture [25, 26]. Vaginal mucosae are not generally affected . Vaginal involvement was described in six women with severe dermatosis . Oral mucosae also remain intact (single cases without the involvement of genitalia were described) [28, 29]. Severe itching worsening at nights is the major subjective symptom in lichen sclerosus et atrophicus . In addition, these women complain of pain, burning, dysuria, vaginal discharge, vaginal bleeding, painful defecation, painful cracks and ruptures after sexual intercourse and defecation . Some women are forced to avoid all sexual activity due to severe dyspareunia .
Lichen simplex chronicus (Vidal) is one of the common dermatoses affecting the anogenital region both in males and females. The precise rate of this disease is unknown. Lichen simplex chronicus typically occurs at the age of 30-50 years.
Lichen simplex chronicus results in a vicious circle of itching, scratching, and inflammation . Specific mechanisms of this vicious circle remain elusive while the initial trigger of itching can rarely be recognized. Infectious or non-infectious itching dermatosis, warmth, sweating, chafing, excessive cleanliness, irritating medications for external use, and sanitary pads may be the trigger . Neuropathic itching is a potential trigger as well: it was demonstrated that lichen simplex chronicus occurs in women with lumbar nerve root compression, postherpetic neuralgia, and diabetic neuropathy . In some dermatoses (e.g., atopic dermatitis), skin is more predisposed to lichenization and lichen simplex chronicus [33, 34].
Permanent, intense, severe itching which is worsened at nights and disturbs sleep is the major symptom of lichen simplex chronicus. Clinical signs of lichen simplex chronicus affecting genitalia range from minimal pigmentation to severe lichenization, erythema, and edema. The lesion has three concentric areas: internal (infiltration), middle (papules), and external (hyperpigmentation). Excoriations and cracksin skin folds as well serous and hemorrhagic crusts are also typical .
Lichen simplex chronicus affecting genitalia is usually bilateral. However, sometimes dominant hand side is more involved. In these patients, skin lesion may be asymmetric or one-sided .
Plasma cell (Zoon’s) vulvitis is a rare chronic idiopathic genital disorder. Plasma cell vulvitis is referred to mucosal diseases (mucous membrane plasmacytosis, or plasma cell mucositis) which include the disorders of the penile shaft (Zoon’s plasma cell balanitis), vermilion border (plasma cell cheilitis), and oral cavity (plasma cell mucositis, atypical gingivostomatitis) .
This condition is relatively uncommon  and often misdiagnosed. It is typical of menopausal women . However, disease onset also occurs in younger age: histologically verified cases were reported at the age of 8 years and 26 years .
Vaginal vestibule, the labia minora, skin around the outlet of the urethra, and (occasionally) clitoris are affected . The lesions are 1-3 cm in size and have irregular shape, well-defined borders, orange-reddish color, and shiny or velvety surface. Dot hemorrhages of more intense color produce a specific cayenne pepper-like appearance. Edema, infiltrates, crusts, or discharge are unusual .
Subjective symptoms of Zoon’s vulvitis are volatile and typically absent. Sometimes, these women complain of itching, burning (predominant symptom), tingling, dysuria, and dyspareunia . In most (73.3%) women, subjective symptoms are severe, and their level does not correlate with the area of lesions and disease duration (see Fig. 2) [40, 41].
Histological pattern and immune phenotype of lichenoid dermatoses
LP is characterized by the appearance of band-like CD3+ T cell infiltrates (at early stages, immunochemistry reveals predominantly CD8+ cells). These infiltrates have well-defined inferior border and are closely adjacent to epidermis thus masking distinct dermoepidermal junction. Occasionally, plasma cells and eosinophils can be found within these infiltrates.
Vacuolization of basal cells (or even the emergence of subepithelial cavities, interface dermatitis, or lichenoid inflammation) is typical of LP. Colloid (Civatt) bodies (degenerative keratinocytes) are found in the deep layers of the stratum spinosum. The thickening of stratum corneum (hyperkeratosis) and stratum granulosum (focal granulosis) are other typical epidermal lesions. Meanwhile, prickles are sharpened thus resembling the teeth of a saw. Pigment is found in the dermis (in particular, at late stages) .
Histological pattern of lichen sclerosus et atrophicus depends on the stage of the illness. Initially, the histological pattern of dermatosis is consistent with interface dermatitis (or lichenoid inflammation), as in LP. Basal membrane thickening, vacuolization of basal cells, and lichenoid infiltrate at the level of dermoepidermal junction composed mainly of lymphocytes and eosinophils are identified. Later stages are characterized by significant edema and homogenization of the fibers of papillary derma, and hyaline deposits under the basal membrane and in perivascular spaces (they can be detected using PAS staining). Inflammatory infiltrates which are mainly composed of CD3+ T cells (CD8 cells prevail over CD4 cells) emerge under the edema. These infiltrates may contain few macrophages, eosinophils, and plasma cells and spread from dermoepidermal junction deep into the dermis.
Histological pattern of lichen simplex chronicus is characterized by significant compact hyperkeratosis, granulosis, acanthosis, pseudoepitheliomatous hyperplasia (occasionally), and hyperplasia of dermal papillae. Mild inflammatory perivascular infiltrates containing melanophages are found in the underlying derma.
In lichen simplex chronicus, histology is useful for excluding other vulvar diseases, e.g., mycosis fungoides and extramammary Paget disease  since the diagnosis is mainly based on clinical presentation. Some studies demonstrate the expression of B7-H3 which regulates the distribution of Langerhans cells and further proliferation of T cells in lichen simplex chronicus .
Zoon’s vulvitis is characterized by the appearance of dense band-like infiltrate which involves papillary derma and may be rather deep (to the middle of the reticular layer). This infiltrate consists of multiple polyclonal plasma cells which sometimes contain Russel bodies. The number of plasma cells varies depending on disease stages (i.e., at later stages, their number increases). Vasodilation, erythrocyte transudation, hemosiderin deposits, and siderophages are found. Over time, fibrosis develops (see Fig. 3) .
The descriptions of the dermatoscopic signs of VLP are scarce. The most typical signs are thick linear curved vessels (hairpin- or spermatozoa-like pattern) distributed diffusely within the lesions, Wickham striae at the periphery of the lesions, skin redness .
Wickham striae are the key sign of LP . These are pearly white (sometimes with a shade of bluish or yellowish) streaks referred metaphorically to as “leaf veins”, “starry sky”, or “radiation” . Dot and/or liner vessels located at the periphery (mainly radially) of lesions may also be found together with Wickham striae.
Pigmentary and long-existing lesions are characterized by dot- or globule-like pigmentary changes (isolated dots or scattered black pepper appearance) commonly arranged chaotically or diffuse hyperpigmentation .
Dermatoscopic signs of vulvar lichen sclerosus et atrophicus are described in few publications [7, 8, 47]. The most typical dermatoscopic signs of vulvar dermatoses are homogenous unstructured bright white areas. They can be uniform and diffuse to form the backdrop of lesions or represented as isolated unstructured white or white pink areas. The morphological basis for these findings is papillary layer sclerosis and epidermal atrophy . White backdrop of lesions is identified by dermatoscopy even in clinically non-obvious cases .
The reduction or even the loss of vascular structures within lesions (compared to the adjacent areas) is another valuable diagnostic criterion of lichen sclerosus et atrophicus [7, 47].
Occasionally, keratin plugs, grey-blue dots, and unstructured reddish-purple areas can be seen inside the lesions. Keratin plugs (follicular keratotic plugs, comedo-like openings) are oval or rounded yellowish or whitish accumulations of keratin in hair follicles. Sometimes they are described as yellowish-white circles . Unstructured reddish-purple areas correspond to hemorrhages which can occur spontaneously as sclerosis progresses. Their size varies from petechia to ecchymosis. They can be seen as dots, globules, or isolated unstructured purple areas at dermatoscopy.
Dermatoscopic signs of vulvar lichen simplex chronicus include the increased number of vessels within the lesions compared to adjacent unaffected areas. Vessels are diffusely distributed within the lesions and can be linear, linear curved (serpentine, wave-like, coiled), or dot-like. The backdrop of these vessels is whitish-grey .
Plasma cell vulvitis is characterized by reddish-orange-yellow lesions and curved linear vessels within the lesions [6, 48]. Typical unstructured reddish-orange-yellow areas are a hallmark of this disease. They may be diffused (i.e., distributed over large areas) or focused . Multiple curved linear vessels vary in their width and shape (e.g., serpentine, spermatozoa-like, coiled, or bowl-shaped). According to the 2019 Consensus on Terminology, these vessels are referred to as linear curved vessels (see Fig. 4).
Clinical presentation of vulvar dermatoses is similar to that of other dermatoses. Meanwhile, the specifics of the affected area account for a modified clinical presentation thus making diagnostic difficulties in vulvar disorders. The cause of diagnostic errors lies in the similarity of the clinical and histological presentations of lichenoid vulvar dermatoses. When diagnosing these conditions, clinical and morphological data should be matched. Different rate of the involvement of oral mucosa, skin, and nails in various dermatoses, a tendency to vulvar scarring and vaginal involvement should be considered. More case reports addressing the sensitivity and specificity of the dermatoscopic signs of vulvar dermatoses are required.
About the authors:
Olga V. Parygina — postgraduate student of the Department of Infectious Diseases, Epidemiology, & Dermatovenerology, St. Petersburg State University, 7/9, Universitetskaya Emb., St. Petersburg, 199034, Russian Federation; dermatovenerologist of the City Dermatovenerological Dispensary, 3, River Volkovka emb., St. Petersburg, 192102, Russian Federation; ORCID iD 0000-0003-2056-9803.
Irina O. Smirnova — Doct. of Sci. (Med.), Associate Professor, professor of the Department of Infectious Diseases, Epidemiology, & Dermatovenerology, St. Petersburg State University, 7/9, Universitetskaya emb., St. Petersburg, 199034, Russian Federation; professor of the Department of Dermatovenerology, I.I. Mechnikov North-Western State Medical University, 41, Kirochnaya str., St. Petersburg, 191015, Russian Federation; dermatovenerologist of the City Dermatovenerological Dispensary, 3, River Volkovka emb., St. Petersburg, 192102, Russian Federation; ORCID iD 0000-0001-8584-615X.
Marianna V. Oganesyan — assistant of the Department of Infectious Diseases, Epidemiology, & Dermatovenerology, St. Petersburg State University, 7/9, Universitetskaya emb., St. Petersburg, 199034, Russian Federation; ORCID iD 0000-0003-0816-8038.
Yanina G. Petunova — Cand. of Sci. (Med.), associate professor of the Department of Infectious Diseases, Epidemiology, & Dermatovenerology, St. Petersburg State University, 7/9, Universitetskaya emb., St. Petersburg, 199034, Russian Federation; dermatovenerologist of the City Dermatovenerological Dispensary, 3, River Volkovka emb., St. Petersburg, 192102, Russian Federation; ORCID iD 0000-0002-6489-4555.
Natal’ya V. Shin — Cand. of Sci. (Med.), associate professor of the Department of Infectious Diseases, Epidemiology, & Dermatovenerology, St. Petersburg State University, 7/9, Universitetskaya emb., St. Petersburg, 199034, Russian Federation; ORCID iD 0000-0002-8138-1639.
Anton R. Zhelonkin — clinical resident of the Department of Infectious Diseases, Epidemiology, & Dermatovenerology, St. Petersburg State University, 7/9, Universitetskaya emb., St. Petersburg, 199034, Russian Federation; ORCID iD 0000-0001-9013-3197.
Angelina O. Zhelonkina — clinical resident of the Department of Infectious Diseases, Epidemiology, & Dermatovenerology, St. Petersburg State University, 7/9, Universitetskaya emb., St. Petersburg, 199034, Russian Federation; ORCID iD 0000-0002-8007-8945.
Contact information: Irina O. Smirnova, e-mail: email@example.com. Financial Disclosure: no authors have a financial or property interest in any material or method mentioned. There is no conflict of interests. Received 12.10.2020, revised 25.10.2020, accepted 03.11.2020.