Localized scleroderma and related comorbidities: a single-centre cohort study.

[BACKGROUND] Localized scleroderma, or morphoea, is a rare autoimmune disease that affects the skin and underlying tissue. It is more common in girls and women than in boys and men. The incidence has two peaks: one in childhood and another in middle-age. Concomitant autoimmune diseases are frequently observed, whereas systemic sclerosis occurs rarely simultaneously.

[OBJECTIVES] To assess the clinical features, comorbidities and treatments of localized scleroderma in Southwest Finland.

[METHODS] Patients diagnosed with localized scleroderma (International Classification of Diseases, 10th Revision code L94) treated between 1 January 2005 and 30 November 2020 were identified from the hospital discharge register of Turku University Hospital, Turku, Finland. Diagnoses were classified into five main types and their subtypes based on the European Dermatology Forum criteria. Basic demographic data, associated comorbidities, and treatments used and their efficacy were recorded.

[RESULTS] A total of 155 people with morphoea were included, with 125 female patients (80.6%) and 30 male patients (19.4%). The most common subtype was limited, plaque-type morphoea (n = 71; 45.8%), followed by the generalized type (n = 57; 36.8%). Fifty-nine concomitant autoimmune diseases were identified in 45 patients (29.0%), most frequently autoimmune thyroid diseases (n = 23; 14.8%). Simultaneous systemic sclerosis was rare (n = 3; 1.9%). The most common malignancy was breast cancer (n = 11; 7.1%). Extracutaneous manifestations were more common in patients with paediatric-onset morphoea (n = 4/27; 14.8%) vs. those with adult-onset disease (n = 2/122; 1.6%). The most commonly used systemic treatment was methotrexate (n = 25; 16.1%), which was beneficial for 64% of the treated patients (n = 16). Phototherapy was administered in 63 of 155 patients (40.6%) and was beneficial in 49 (78%).

[CONCLUSIONS] At our centre, patients with morphoea often require systemic immunomodulatory treatment or phototherapy. The incidence of the generalized subtype and the occurrence of concomitant autoimmune diseases, particularly thyroid autoimmune diseases, is relatively high. No evidence of an increased risk of malignancy was found in these patients.