Lichen Sclerosus et Atrophicus on the Underarms and Torso

Lichen sclerosus et atrophicus (LSA) is a chronic, skin-limited disease that can cause significant symptoms, disfigurement, and disability. Although the etiology is still uncertain, autoimmune and genetic factors seem to play a significant role in the pathogenesis of this disease. While the diagnosis is clinical and confirmed via histology, noninvasive imaging modalities such as dermatoscopy and confocal microscopy may play a significant role. High-potency topical corticosteroids and calcineurin inhibitors remain the mainstay of treatment for patients with this disease.

A 28-year-old woman presented to our clinic with hypopigmented, atrophic macules coalescing into large patches on the right lateral neck. The lesions initially started as scattered spots on the neck and subsequently spread to the right shoulder, right axilla, bilateral medial breasts, and abdomen (Figure 1). The patches were asymptomatic.

A physical examination revealed hypopigmented, annular, atrophic patches across the torso. The patient had no family history of similar lesions or known medical problems, was taking no medications, and denied trauma to the areas.

The initial clinical presentation of our patient suggested extragenital LSA given the morphology of the lesions and their characteristic distribution. The patient did not have genital involvement. However, other diagnoses were considered, and a skin biopsy was performed. 

Histologic evaluation showed follicular plugging, a band of inflammatory cells, sclerosis of the papillary dermis, and pigment incontinence (Figures 2 and 3). These findings were consistent with early extragenital LSA. The patient was prescribed high-potency topical corticosteroids with significant improvement upon follow-up.

LSA is a benign, chronic, inflammatory, lymphocyte-mediated scarring of the epidermis and the dermis.¹The disease was originally described by Francois Henri Hallopeau in 1887. This condition typically presents in the genital region, with anogenital LSA comprising about 85% of cases.²The involvement of the glans penis is known as balanitis xerotica obliterans, while vulvar involvement is known as kraurosis. Other complications of this condition may include intraepithelial dysplasia, which may progress to squamous cell carcinoma.³

LSA can occur at any age, although the prevalence is highest in adult perimenopausal women. The disease has a bimodal peak of incidence in prepubertal children and postmenopausal women/middle-aged men. In both sexes, anogenital involvement is most common. In girls, it might present as hemorrhagic perianal lesions and may be mistaken for sexual abuse.

The pathogenesis of this disease remains unclear. Several hypotheses regarding the pathophysiological mechanism contributing to the disease presentation are suggested in the literature, including infection, autoimmune dysregulation, genetics, and hormonal factors.² There is a myriad of explained theories for the cause of LSA. For example, low estrogen has been theorized as a contributing factor given that it leads to vulvar atrophy in elderly, postmenopausal women. Two possible infectious triggers—human papillomavirus and acid-fast bacteria—have been claimed to cause LSA. The autoimmune response seems to be related to Th-1 response, which leads to a chronic inflammatory condition and an activation of signaling pathway involving fibroblast and collagen metabolism.³ It is also suggested that LSA might have a genetic predisposition. Affected patients may carry a gene for the disease that might be effectively expressed after environmental triggers.

Classically, LSA presents as a hypopigmented, ivory-colored, scaly, atrophic patch or thin plaque. Extragenital presentation is uncommon, but when it occurs, it classically affects the upper trunk, neck and shoulders, axilla, upper arms, flexor wrists, and around the umbilicus. Extragenital scrotal involvement is uncommon in men, despite common genital and vulvar involvement in women.^4,5 LSA may also coexist with lichen planus and morphea.⁶ LSA can be associated with allergic contact dermatitis to nickel and segmental cherry angiomas.^7,8

A hypertrophic variant of LSA has been reported in the literature with psoriasiform lichenoid dermatitis visible on histology.⁹ Hypertrophic lichen sclerosus is characterized by the development of hyperkeratosis, dyskeratosis, and parakeratosis. In sclerotic lesions, dissolution of elastic fibers is characteristic of the disease. In nonsclerotic lesions, the recognition of follicular hyperkeratosis and thickening of basement membrane might be a helpful clue in some individual cases.

In early stages, the presentation of LSA might be nonspecific. Only chronic and old lesions usually exhibit the classic features of LSA. The microscopic features of early lesions may have lichenoid changes and present as dermal edema and interface dermatitis. In the later stages of the disease, the lesions show hyalinization with orthokeratotic hyperkeratosis, thinned epidermis, hydropic degeneration of the basal layer, superficial dense homogenous dermal fibrosis, and chronic inflammatory infiltrates in the upper dermis. Usually, the classic histologic features of lichen sclerosus are seen in both vulvar and extragenital lesions. However, vulvar lichen sclerosus lesions have a higher mean epidermal thickness of more than 3 times of that seen in extragenital lichen sclerosus. Also, vulvar lichen sclerosus tends to have a more sclerotic with inflamed dermis. Carcinoma associated lichen sclerosus tends to show exaggerated epidermis thickness, basal atypia, and loss of the edematous-hyaline layer.¹⁰

A variety of disorders may present similarly to extragenital lichen sclerosis (Table). For example, lichen planus presents as polygonal, violaceous, pruritic plaques with overlying white reticulated stripes. However, vulvar lichen planus presents as painful patches mainly in the vaginal introitus with reticulated hyperkeratosis at the edge of the lesion (Wickham striae).¹¹ While early lesions of LSA may present similarly to lichen planus, the presence of basal layer squamatization, pointed rete ridges, and the presence of superficial elastic fibers favors the diagnosis of lichen planus rather than LSA.

Morphea/scleroderma also presents as ivory-shiny plaques and resembles LSA. Under microscopy, the architecture of the homogenization of the papillary dermis in morphea may mimic LSA. However, the preservation of the superficial elastic fibers and thickened collagen bundles in the reticular dermis favors the diagnosis of morphea over LSA.

Although chronic radiation dermatitis and LSA may be challenging to differentiate, the following features on histopathology may be helpful: the presence of ecstatic blood vessels in the upper dermis and stellate fibroblasts are more suggestive of radiation dermatitis. In contrast, a lichenoid interface dermatitis and an atrophic upper dermis are more consistent with LSA. Radiation-induced LSA of the vulva was reported for the first time in the literature in 2017.¹² Several cases of postirradiation extragenital LSA have been reported in the literature.^13,14

Mycosis fungoides, the great imitator, should also be included in the differential diagnosis. It typically presents as erythematous patches or plaques.¹⁵ Histologically, early lesions are sometimes indistinguishable from LSA and other common inflammatory skin diseases. Later lesions are characterized by band-like papillary dermal infiltrates, intraepidermal lymphocytes, and dermal reticular fibroplasia.¹⁶

Vitiligo is also a consideration and presents as clearly defined depigmented macules and patches.¹⁷ More concerning conditions, such as vulvar intraepithelial neoplasia, can be considered in the differential diagnosis as well.

The first guidelines for the management of genital and extragenital LSA were published in 2002 by the British Association of Dermatologists. Two updates of these guidelines have been published since their first release, one in 2010 and one in 2018.¹⁸ The aim was to offer evidence-based management of LSA in both adult and pediatric patients.¹⁹

Since the etiology and pathophysiology of LSA is still unknown, a targeted therapy is yet to be determined in the clinical setting. The first-line management for LSA consists of potent topical corticosteroids, such as clobetasol propionate, 0.05% ointment once or twice daily for 1 to 3 months.²⁰  A confident decision on the appropriate corticosteroid potency and duration of use remains the main challenge in managing LSA, especially when treating LSA in children. Other therapeutic options with promising efficacy for erosive LSA include treatment with methylaminolevulinic acid and laser-mediated photodynamic therapy.^21,22 A significant positive response to methotrexate alone or in combination with other treatment options is widely studied.²³ An effective combination of pulsed high-dose corticosteroids combined with low-dose methotrexate in patients with refractory generalized extragenital LSA was described in the literature.²⁴ This treatment modality is widely applied in clinical practice.

A complete resolution of extragenital LSA with pulsed dye laser is a preferrable treatment option.²⁵ Although the mechanism is still unknown, the absence of skin pigmentation and scarring made this option a desirable treatment by the treating dermatologists.²⁵ Also, 3 months of treatment with oral psoralen plus ultraviolet A showed completely resolved extragenital LSA without recurrence of the disease.²⁶ Because management of the disease is a clinical challenge, several unsuccessful treatment options were described in multiple studies. For example, a solitary treatment with topical pimecrolimus, 1% ointment showed ineffectiveness for the treatment of extragenital LSA.²⁷