Morphea is a skin dermatosis that is idiopathic in nature. The most common form is solitary, but many clinical variants have been described, including linear, guttate, and generalized forms. A small subset of patients (<1%) progress to progressive systemic sclerosis. It is likely that many patients do not seek medical advice because the onset is insidious or the area of involvement is so small that it is hardly noticeable or bothersome.
Clinical Findings: Morphea is typically seen in young Caucasian females. The ratio of females to males has been estimated at 2:1. Morphea begins as a small erythematous macule. The lesion expands outward with a violaceous to red border. As it expands, the central portion becomes slightly hypopigmented and indurated in nature. The trunk is the most commonly involved region of the body. Most areas of involvement are asymptomatic to slightly pruritic. If the involved area crosses over a joint, there may be some loss of motion of the affected joint and pain with flexion and extension. The main differential diagnosis is between morphea and lichen sclerosis et atrophicus. Lichen sclerosis et atrophicus is typically more strikingly white in coloration and is less indurated.
Many variants of morphea have been described. Guttate morphea manifests with tiny, teardropshaped areas of hypopigmented macules with slight induration scattered about the trunk or extremities. The induration of guttate morphea is not nearly as prominent as that of localized morphea and may not be appreciable. These guttate lesions may be impossible to distinguish clinically from lichen sclerosis et atrophicus, and a biopsy is the only way to differentiate the two. Biopsies are not always conclusive, and the term morphealichen sclerosis overlap has been used to describe these lesions with features of both conditions. Generalized morphea is a rare variant with extensive involvement of the cutaneous surface. By definition, generalized morphea does not have systemic involvement, differentiating it from progressive systemic sclerosis. However, patients with generalized morphea may develop atrophy of the adipose and muscle tissues underlying the areas of involvement. Linear morphea, also called linear scleroderma, is a unique cutaneous variant that is well described and has a distinctive appearance and potential underlying com- plications. It is commonly found along the length of the affected extremity. This form occurs most commonly in childhood. The affected skin may become bound down and cause limb length discrepancies as the child grows. Joint mobility is also a potential complication. Cortical hyperostosis of the long bones underneath the area of linear morphea has been well reported and is termed melorheostosis. There are subtypes of linear morphea that have been given the names en coup de sabre and Parry-Romberg syndrome.
En coup de sabre is a specific type of morphea that occurs along the forehead, as well as partially onto the cheek and into the scalp. It appears as a depressed linear furrow from the scalp vertically down the fore-head. The appearance can be subtle or extremely noticeable and can cause significant cosmetic problems. Parry-Romberg syndrome is a name given to linear morphea that occurs vertically across the face, causing hemifacial atrophy. The underlying adipose tissue, muscle, and bone are involved, with significant disfigurement. Patients may have neurological involvement leading to seizures.
Pathogenesis: The pathogenesis of morphea is poorly understood. An unknown factor sets off this cutaneous reaction in which an excessive amount of collagen is produced locally by fibroblasts. Potential factors that may initiate the reaction are endothelial damage, certain Borrelia burgdorferi infections, and fibroblast abnormalities that lead to increased collagen production. Borrelia-induced morphea has yet to be described in the United States; it has been reported in Europe and Asia.
Histology: A punch biopsy specimen of morphea appears as a nicely formed cylinder. The dermis is expanded with excessive amounts of collagen. A slight inflammatory infiltrate is often seen along the dermalsubcutaneous border. Plasma cells are common.
Treatment: Therapy for localized morphea is not needed but can be attempted with topical corticosteroids, calcipotriene, and phototherapy. Linear morphea should be treated, because it has significant functional and cosmetic implications. Immunosuppressive agents such as methotrexate and prednisone have been the most thoroughly studied therapeutic agents.