Cutaneous sarcoidosis: clinical presentation and diagnostic difficulties

Sarcoidosis is a systemic granulomatous disease of unknown origin affecting mainly lungs, lymph nodes, skin, eyes and less frequently liver, spleen, parotid glands, central nervous system and bones. Skin lesions are present in 25% of patients with sarcoidosis and can be specific with sarcoidal granuloma formation or nonspecific presenting mostly as erythema nodosum. Specific skin lesions observed in 16-37% of patients are polymorphic, can mimic other cutaneous disorders, and may cause many diagnostic problems. The clinical diagnosis should be confirmed histopathologically. The most common form of cutaneous sarcoidosis is maculopapular variety and other forms, i.e. lupus pernio, angiolupoid, annular, nodular and subcutaneous varieties, are less frequent. In some patients sarcoidal granulomatous infiltration of old scars (scar sarcoidosis) can be observed. Cutaneous lesions may occur in any stage of sarcoidosis, mainly at the onset of the disease. In some patients they are the initial symptom, and in rare cases only skin involvement may be present. Diagnostic value of cutaneous sarcoidosis is commonly recognized but its prognostic significance is still not clear. All authors are in agreement that erythema nodosum is a marker of acute, self-limiting sarcoidosis and lupus pernio appears in the late, chronic stage of the disease. The course of lupus pernio may be protracted and in some patients is refractory to therapy with corticosteroids. All cases of cutaneous sarcoidosis should be screened for visceral involvement, since the course, mode of therapy and prognosis are related to systemic disease.