Skin manifestations of sarcoidosis.

The skin manifestations of sarcoidosis are classified as specific, where biopsy reveals non-caseating granulomas, and non-specific, typically erythema nodosum. The most frequent specific (granulomatous) skin lesions are maculopapules, subcutaneous nodules, scar sarcoidosis, plaques and lupus pernio. Skin biopsy allows early diagnosis of sarcoidosis through a non-aggressive procedure. In sarcoidosis, erythema nodosum is usually associated with bilateral hilar lymphadenopathy on the chest radiograph, this being known as Löfgren's syndrome. Cutaneous lesions have prognostic significance. Löfgren's syndrome is usually associated with good prognosis and spontaneous resolution. Maculopapular lesions and subcutaneous nodules are more often associated with remission of the systemic disease at two years, while plaques and, mainly, lupus pernio are hallmarks of chronic disease. Most cutaneous lesions of sarcoidosis are only mildly symptomatic and do not require treatment. However, chronic skin lesions, particularly lupus pernio, are disfiguring and can have a strong psychological and social impact. Treatment of these lesions is a challenge since they do not respond well to conventional treatments. The introduction of biological agents has been an important although not definitive advance in the treatment of cutaneous sarcoidosis.