Skin manifestations in sarcoidosis

Almost a century ago, the relationship of sarcoid infiltrations of the skin and granulomatous changes in other organs was recognised. Schaumann, in 1914, proposed that lupus pernio (fig. 1a–c) could be a manifestation of a generalised disease. Later on, a variety of skin manifestations have been described to occur more or less frequently. Lupus pernio indicates an unfavourable prognosis, whereas in the case of erythema nodosum (EN) (fig. 2), disease remission generally occurs within months or a few years [1–4]. The histopathological characteristics of the two findings are totally different, reflecting the variable clinical picture and outcome in this inflammatory disorder where the antigen(s) still are unknown [5, 6]. Beside these two extremes, there are a number of other more or less common skin lesions having either a maculopapular, subcutaneous, cicatricial or plaque character. In this chapter, a sharp distinction will be made between nonspecific lesions, i.e. erythema nodosum, and specific skin manifestations, e.g. lupus pernio. The frequency of skin lesions in sarcoidosis varies depending on the intensity by which they are looked for [7, 8], as well as on the ethnic background of the patients [5, 6]. In Scandinavia, about one-third of the patients born there will present with EN as part of Lofgren’s syndrome [2]. However, in Japanese patients, this syndrome is less common. In contrast, lupus pernio is very infrequent in Scandinavia, but more common among African Americans in the USA [5, 6]. On an average, y25% of sarcoidosis cases have cutaneous involvement, which may appear at any stage of the disease [5, 9, 10]. More recently, Yanardag et al. [7] reported a higher percentage (almost 33%) of skin manifestations among w500 Turkish patients. Roughly, 20% of them had EN. The frequency of reported specific cutaneous involvement in sarcoidosis ranges from 10–40%.