MORPHEA
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.
