Nicolau's syndrome after local glucocorticoid injection.

We report three cases of Nicolau's syndrome induced by intraarticular glucocorticoid injections. Nicolau's syndrome is defined as livedo-like dermatitis secondary to acute arterial thrombosis occurring immediately after intravascular injection of an insoluble drug substance. The cases described by Nicolau occurred in association with injections of oily bismuth suspensions. In 1970s and 1980s, cases occurred with delayed-action penicillin suspensions injected intramuscularly. Typically, the injection is followed immediately by excruciating pain in the buttock, sometimes with syncope. Cyanotic patches and a livedoid pattern develop. Rapid resolution of the pain and slower clearing of the skin changes occur in most patients. We report three typical cases with both severe pain and skin changes. In addition, two other patients had incomplete variants without skin abnormalities. Each of these five patients had received an injection in or about a joint of a glucocorticoid in a crystalline suspension. The pathophysiology of this syndrome probably involves acute vascular spasm related to penetration of microcrystals into a blood vessel.