Skin involvement and outcome measures in systemic autoimmune diseases.
This paper focuses on skin manifestations that can be observed in autoimmune diseases such as rheumatoid arthritis (RA), Sjögren syndrome (SS), dermatomyositis (DM) and Behçet syndrome (BS). In RA the most widely recognized skin lesion is the rheumatoid nodule. Other cutaneous manifestations can be observed either non-specific or related to the disease itself and/or to the commonly used drugs. Cutaneous manifestations are considered one of the most typical extraglandular features of primary SS, generally they are distinguished in vasculitic and non vasculitic lesions. Among non-vasculitc lesions, skin dryness (xerosis) has been shown to be very common in pSS while vasculitis lesions include typically flat and palpable purpura and urticarial vasculits. In DM the skin manifestations are also frequent and include a heliotrope rash (blue-purple discoloration) on the upper eyelids with edema, a flat red rash on the face and upper trunk, and erythema of the knuckles with a raised violaceous scaly eruption (Gottron rash). The most frequent mucocutaneous finding in BS is aphthous stomatitis which can not usually be differentiated from idiopatic reccurrent aphthous stomatitis on clinical grounds. The most typical skin manifestations are nodular lesions, which are commonly seen in BS and may be due to panniculitis [erythema nodosum (EN)-like lesions] or superficial thrombophlebitis.