Localized scleroderma (ORPHA:90289)
A rare skin disease characterized by inflammatory and sclerosing disease affecting the skin and underlying connective tissues (subcutaneous tissue, fascia, muscle or bone). It causes cutaneous patches or bands of skin inflammation and thickness affecting the head, neck region, trunk and extremities.
Epidemiology
The incidence of localized scleroderma has been estimated at 1/37,000-625,000 people per year depending on the country. Women are predominantly affected (F/M sex ratio around 3:1). The mean age at diagnosis ranges from 8 to 47 years. In two-thirds of cases, it occurs in adults. Localized scleroderma is called ''juvenile'' when occurring in childhood (peak incidence between 7 and 11 years).
Clinical description
Localized scleroderma is classified into several subtypes (there is no consensual classification) that include limited (circumscribed or plaque morphea), generalized (≥4 lesions and/or ≥2-3 anatomical sites) or pansclerotic morphea, and linear morphea. Linear morphea tends to affect children and adolescents, while plaque morphea is more common in adults. However, both can coexist in the same patient (mixed morphea). First, areas of hard and dry skin develop in the hands, arms, face, or leg in an ipsilateral fashion. Then, plaques that spread centrifugally or wide strips (linear scleroderma) appear. Plaques are round or oval, often with a white appearance and a violaceous border. Linear scleroderma mainly develops on the face, thorax, arms, and legs. In the case of facial involvement, some strips developing on the forehead may be hollow and lead to a sabre-cut appearance (termed ''en coup de sabre''). Linear scleroderma tends to involve the underlying fat and muscles and may lead to muscle atrophy, ophthalmologic or neurological disorders such as headaches, seizures or uveitis. Localized scleroderma can result in major facial or limb asymmetry, flexion contractures, and disability. Raynaud's phenomenon is usually absent. It is important to note that localized scleroderma does not evolve into systemic sclerosis (rarely, systemic sclerosis and localized scleroderma can co-exist).
Etiology
The exact cause of localized scleroderma is unknown. The disease originates from a combination of genetic predisposition and environmental factors, implies vascular and autoimmune pathways which lead to localized overproduction of extracellular matrix (collagen).
Diagnostic methods
Diagnosis is based on clinical presentation. A skin biopsy may help to confirm the diagnosis by revealing abnormal accumulation of collagen, thickening of the vessel walls, and the presence of inflammatory infiltrates in the papillary dermis and around the vessels. Blood tests are usually normal. Some patients may have antinuclear antibodies excluding systemic sclerosis-associated specificities (anti-topoisomerase, anti-centromere or anti-RNA polymerase III antibodies).
Differential diagnosis
The differential diagnosis includes (but is not limited to): lichen sclerosus, granuloma annulare, erythema chronicum migrans, drug-induced dermatitis, eosinophilic fasciitis or systemic sclerosis, especially in case of generalized/pansclerotic morphea.
Management and treatment
Management is symptomatic and includes the use of topical steroids, tacrolimus, vitamin D derivates or imiquimod for morphea lesions, and systemic steroids, methotrexate or phototherapy for linear scleroderma of the neck and extremities with potential functional/esthetic consequences, or for generalized morphea. Treatment should be initiated promptly to prevent irreversible tissue damage. Physical therapy may be helpful to limit cutaneous indurations and muscle retraction.
Prognosis
Prognosis is usually favorable within 5 years but some patients may present with chronic disease and recurrences. Localized scleroderma is only rarely life threatening but can severely affect quality of life, particularly in children. Linear lesions tend to persist longer than plaque lesions.

                            Last update: 
                            February 2024


                            - Expert reviewer(s): 
                            Pr Vincent SOBANSKI