Version May 2024
INTRODUCTION — Lichen sclerosus (also known as lichen sclerosus et atrophicus) is a chronic, inflammatory skin disorder characterized by atrophic plaques on the skin or mucous membranes. Genital lichen sclerosus, particularly vulvar lichen sclerosus, is considered the most frequent presentation. (See "Vulvar lichen sclerosus: Clinical manifestations and diagnosis".)
Extragenital lichen sclerosus refers to lichen sclerosus in sites other than the anogenital area. Extragenital involvement typically presents as porcelain-white, hypopigmented, or hyperpigmented, atrophic plaques (picture 1A-E) and may accompany genital lichen sclerosus, occur alone, or overlie lesions of morphea (localized scleroderma). (See "Vulvar lichen sclerosus: Clinical manifestations and diagnosis" and "Pathogenesis, clinical manifestations, and diagnosis of morphea (localized scleroderma) in adults".)
The clinical features and diagnosis of extragenital lichen sclerosus will be reviewed here. The management of extragenital lichen sclerosus and the diagnosis and management of genital lichen sclerosus are discussed separately.
●(See "Extragenital lichen sclerosus: Management".)
●(See "Vulvar lichen sclerosus: Clinical manifestations and diagnosis".)
●(See "Balanitis in adults".)
EPIDEMIOLOGY — The true prevalence of extragenital lichen sclerosus is unknown, but the disorder appears to occur less frequently than genital lichen sclerosus [1-3]. Extragenital lichen sclerosus often occurs in association with genital lichen sclerosus. (See 'Concomitant genital involvement' below.)
Similar to genital lichen sclerosus, extragenital disease appears to be more common in females than males. In a retrospective review, 17 out of 20 patients with histopathologic findings consistent with extragenital lichen sclerosus were female [4].
PATHOGENESIS — The pathogenesis of lichen sclerosus is poorly studied. Most information on this subject has been derived from studies on genital disease.
Proposed etiologic factors for lichen sclerosus include immune dysfunction, genetic predisposition, infectious agents, and trauma [5-14]. In addition, the development of extragenital lichen sclerosus in patients with metastatic melanoma treated with ipilimumab in combination with nivolumab or other checkpoint inhibitors is described in case reports [15]. (See "Vulvar lichen sclerosus: Clinical manifestations and diagnosis", section on 'Etiology'.)
CLINICAL MANIFESTATIONS — Extragenital lichen sclerosus can occur in any location on the skin and infrequently appears in the oral cavity. Conjunctival lesions do not occur. Concomitant genital lichen sclerosus or morphea lesions may be present [16]. (See 'Concomitant genital involvement' below and 'Concomitant morphea' below.)
Cutaneous lesions — Cutaneous findings evolve over time, have a variable distribution, and may present with associated symptoms:
●Morphology – Early, active skin lesions of extragenital lichen sclerosus often appear as flat-topped and slightly scaly, hypopigmented, white, or mildly erythematous, polygonal papules that may coalesce to form larger plaques with peripheral erythema (picture 2A-C). Over time, as activity subsides, lesions may develop a porcelain-white color; variable degrees of palpable sclerosis; and a cigarette paper-like, wrinkled appearance that correlates with epidermal and superficial, dermal atrophy (picture 1A, 1C-D, 1F). In individuals with highly pigmented skin, established lesions may demonstrate hyperpigmentation and hypopigmentation rather than a porcelain-white color (picture 1B, 1E) [17].
Telangiectasias; follicular, keratotic plugs; and hemorrhagic or nonhemorrhagic bullae may also be present (picture 3) [18,19]. Examples of reported dermoscopic findings include structureless, white to yellow areas; chrysalis-like structures; linear, irregular vessels; perifollicular scaling; keratotic plugs; and rosettes [20-22].
●Distribution – Extragenital lesions are commonly found on the back, shoulder, neck, wrist, thigh, and inframammary areas [23,24]. In our experience, the lesions are often symmetrically distributed and located in areas of chronic friction. Cutaneous lesions following the lines of Blaschko (figure 1) have also been reported [25,26].
●Symptoms and complications – Extragenital lichen sclerosus ranges from an asymptomatic condition involving limited body sites to widely distributed lesions that can be severely disabling. Patients experience pruritus, a sensation of burning skin, and/or painful fissuring. Such symptoms may be more frequent when lesions are located in areas subject to friction or tension, such as the inframammary folds, antecubital fossae, axillae, waist, inguinal creases, and popliteal fossae. Bullae may develop, often with hemorrhage resulting in erosions.
Extragenital lichen sclerosus can negatively impact quality of life by limiting clothing choices, inhibiting participation in occupational and leisure activities, and contributing to concern about the appearance and texture of affected skin. In addition, trauma to unaffected skin, such as injury from tight clothing, injections, radiation therapy, herpes zoster, or other factors, may precipitate new lesions (Koebner phenomenon) (picture 4) [13,14,27-29].
In the author's experience, the residual atrophic cutaneous changes of lichen sclerosus are prone to xerosis as well as asteatotic and irritant dermatitis. Patients often require active management of these complications.
Oral lesions — Oral lichen sclerosus is rare and involves the lips, gingiva, palate, tongue, or buccal mucosa in children and adults [30-33]. Lesions often appear as irregular, white or hypopigmented plaques and may be atrophic, causing gingival recession. Most patients are asymptomatic but may experience pruritus, burning, or tightness in affected areas [30,31,34]. Oral lesions may present independently or in association with lichen sclerosus in other sites [35]. (See "Extragenital lichen sclerosus: Management", section on 'Oral disease'.)
Concomitant genital involvement — Coexistence with genital involvement may be common, warranting evaluation for genital involvement in all patients [1-3]. In one series of 355 female adults and children with genital and/or extragenital lichen sclerosus, approximately 16 percent had both extragenital and genital lesions, and only 3 percent had isolated extragenital lesions [2]. (See 'Diagnosis' below.)
Concomitant morphea — Clinical findings consistent with genital or extragenital lichen sclerosus may occur in patients with morphea (picture 5A-B) [36-39]. It is unclear whether the appearance of lesions consistent with lichen sclerosus represents the simultaneous occurrence of two separate disorders or the development of clinical findings that resemble lichen sclerosus in lesions of morphea. (See "Pathogenesis, clinical manifestations, and diagnosis of morphea (localized scleroderma) in adults", section on 'Clinical manifestations'.)
The frequency of extragenital lichen sclerosus in patients with morphea was evaluated in a retrospective study of 381 adults and 91 children with morphea [37]. Extragenital lichen sclerosus was detected in 19 patients (4 percent). Additional studies are necessary to confirm the frequency of extragenital lichen sclerosus in this population. (See "Pathogenesis, clinical manifestations, and diagnosis of morphea (localized scleroderma) in adults", section on 'Lichen sclerosus' and "Pathogenesis, clinical manifestations, and diagnosis of morphea (localized scleroderma) in adults", section on 'Generalized morphea'.)
The potential for coexisting morphea and genital lichen sclerosus supports performing genital examinations in patients with morphea. In the author's practice, most patients with morphea and genital lichen sclerosus have been postmenopausal females in whom features of extragenital lichen sclerosus accompany morphea. (See "Pathogenesis, clinical manifestations, and diagnosis of morphea (localized scleroderma) in adults", section on 'History and physical examination'.)
HISTOPATHOLOGY — The characteristic pathologic features of lichen sclerosus include (picture 6) [4]:
●Epidermal hyperkeratosis with follicular plugging
●Epidermal atrophy with flattening of rete ridges
●Vacuolization of the basal layer of the epidermis
●Marked edema in the superficial dermis (early lesions)
●Homogenized collagen in the upper dermis (established lesions)
●Lymphohistiocytic infiltrate underlying the zone of homogenized collagen
DIAGNOSIS — The diagnosis of extragenital lichen sclerosus can often be made based on the clinical appearance, particularly in patients with porcelain-white, atrophic lesions. (See 'Cutaneous lesions' above.)
When the diagnosis is uncertain, such as when features suggestive of other disorders are also present, a punch biopsy is useful for confirming the diagnosis. (See 'Differential diagnosis' below and "Skin biopsy techniques", section on 'Punch biopsy'.)
●Additional clinical assessment – Patients with skin findings consistent with extragenital lichen sclerosus should undergo a complete examination of the skin, oral cavity, and external anogenital skin. This allows for the assessment of the extent of skin disease and the identification of patients with associated oral or genital lichen sclerosus or morphea. The recognition of genital lichen sclerosus is particularly important because of its association with an increased risk for squamous cell carcinoma. Patients may be unaware of genital lesions or hesitant to mention them. (See "Vulvar lichen sclerosus: Clinical manifestations and diagnosis", section on 'Association with malignancy'.)
Recognition of patients with a history of immune checkpoint inhibitor therapy may also be relevant. Extragenital lichen sclerosus has been reported in patients treated with immune checkpoint inhibitors [15]. However, an association has not been confirmed. (See 'Pathogenesis' above.)
●Role of histopathology – The identification of characteristic histopathologic findings in biopsies of lesions suspicious for extragenital lichen sclerosus is almost always indicative of the diagnosis (picture 6). Although similar histopathologic findings occur in the lichen sclerosus-like variant of chronic graft-versus-host disease, the clinical history facilitates the differentiation of these disorders. (See 'Histopathology' above and "Cutaneous manifestations of graft-versus-host disease (GVHD)", section on 'Diagnosis' and 'Differential diagnosis' below.)
DIFFERENTIAL DIAGNOSIS — A variety of disorders may present with clinical features that resemble extragenital lichen sclerosus. Examples include:
●Vitiligo – Vitiligo is characterized by the presence of well-demarcated, depigmented patches on the skin (picture 7A-B). In contrast to extragenital lichen sclerosus, skin texture is normal, without signs of atrophy or sclerosis. (See "Vitiligo: Pathogenesis, clinical features, and diagnosis", section on 'Clinical features'.)
●Lichen planus – Extragenital lichen sclerosus may present as violaceous, polygonal papules on the wrists or ankles that closely resemble lichen planus (picture 8A-B) [40,41]. Unlike extragenital lichen sclerosus, lichen planus is often pruritic. A skin biopsy can be used to distinguish between these disorders. (See "Lichen planus".)
●Tinea versicolor – Tinea versicolor presents with hypopigmented macules and patches primarily located on the trunk and proximal upper extremities (picture 9A-B). Fine scale is often evident, and a potassium hydroxide preparation will reveal the presence of fungal elements. Signs of cutaneous atrophy and sclerosis are absent. (See "Tinea versicolor (pityriasis versicolor)" and "Office-based dermatologic diagnostic procedures", section on 'Potassium hydroxide preparation'.)
●Anetoderma – In anetoderma, loss of elastin in the dermis contributes to reduced skin elasticity and the appearance of circumscribed, 1 to 3 cm areas of depressed, flaccid, wrinkled, or bulging skin (picture 10). Anetoderma may occur as a primary disorder or as a result of a preceding, inflammatory process or other skin abnormality. The neck, trunk, and upper extremities are most frequently affected. (See "Anetoderma".)
●Cutaneous T cell lymphoma – Like extragenital lichen sclerosus, lesions of patch-stage mycosis fungoides may present with epidermal atrophy manifesting as fine, cigarette paper-like wrinkling (picture 11A-B). Lesions of mycosis fungoides are often erythematous, resembling an eczematous dermatitis. Hypopigmented mycosis fungoides presents with hypopigmented patches (picture 12A-B). (See "Clinical manifestations, pathologic features, and diagnosis of mycosis fungoides", section on 'Skin lesions'.)
●Chronic graft-versus-host disease – Patients who have received hematopoietic cell transplants may develop lesions that closely resemble extragenital lichen sclerosus as a manifestation of chronic graft-versus-host disease (picture 13). Knowledge of the patient's transplant history is useful for diagnosis. (See "Cutaneous manifestations of graft-versus-host disease (GVHD)", section on 'Sclerotic manifestations'.)
●Morphea – Skin lesions that resemble the classic, atrophic, white patches of extragenital lichen sclerosus may develop in individuals with morphea, an idiopathic, inflammatory disorder that causes sclerotic changes in the skin. The relationship between morphea and lichen sclerosus remains unclear. (See 'Concomitant morphea' above and "Pathogenesis, clinical manifestations, and diagnosis of morphea (localized scleroderma) in adults".)
SUMMARY AND RECOMMENDATIONS
●Epidemiology – Extragenital lichen sclerosus is an uncommon disorder that may involve the skin or oral cavity. The disorder occurs more frequently in females than in males, and the occurrence in children is rare. (See 'Epidemiology' above.)
●Clinical manifestations:
•Cutaneous lesions – Early, active skin lesions of extragenital lichen sclerosus often present as flat-topped, polygonal papules that may coalesce into large plaques (picture 2A-C). Inactive lesions can develop a porcelain-white color, a finely wrinkled surface, and variable degrees of sclerosis (picture 1A, 1C-D). In individuals with highly pigmented skin, lesions may be hyperpigmented or hypopigmented (picture 1B, 1E). (See 'Cutaneous lesions' above.)
•Oral lesions – Oral lichen sclerosus presents as irregular, white or hypopigmented plaques on the lips or in the oral cavity. (See 'Cutaneous lesions' above.)
●Diagnosis – A variety of other skin disorders share clinical features with extragenital lichen sclerosus. When the diagnosis is uncertain based upon clinical examination, a skin biopsy should be performed. (See 'Diagnosis' above and 'Differential diagnosis' above and 'Histopathology' above.)
●Assessment for concomitant disorders – Extragenital lichen sclerosus can occur in association with genital lichen sclerosus or morphea. A complete examination of the skin, oral cavity, and external anogenital skin should be performed to identify patients with these disorders. (See 'Concomitant genital involvement' above and 'Concomitant morphea' above.)
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