Dermatitis granulomatosa intersticial

Abstract

Interstitial granulomatous dermatitis is an uncommon disease that is currently being defined. In general terms, this entity is characterized by a granulomatous inflammation of the skin within the context of a systemic disease, the most usual being autoimmune diseases. The difficulty of defining interstitial granulomatous dermatitis is due to its clinical and microscopic heterogeneity and the proliferation of terms used to denote this dermatosis. Clinically, interstitial granulomatous dermatitis may appear as subcutaneous linear cords on the trunk or as papules or plaques. Linear lesions have been considered as pathognomonic for this disease but are the least frequent lesion. The most common are papular eruptions, followed by erythematous plaques. Typical histopathologic findings consist of a granulomatous infiltrate composed of histiocytes distributed interstitially and in palisaded array within the reticular dermis, plus a variable number of neutrophils and eosinophils. Leukocytoclastic vasculitis can be the main finding among initial lesions. The importance of interstitial granulomatous dermatitis lies in its almost constant association with systemic disease, the most common being rheumatoid arthritis. The spectrum of associated diseases has increased in the last few years and includes other autoimmune diseases as well as several drugs, neoplasms and infections. Thus, this dermatosis should be considered as a marker of systemic disease, which must be excluded by history taking and complementary examinations.