Retiform Purpura and Digital Gangrene Secondary to Antiphospholipid Syndrome Successfully Treated With Sildenafil

Abstract

A 16-year-old African American female adolescent with a 2-year history of systemic lupus erythematosus (featuring a malar erythema, photosensitivity, arthritis, and anemia in the setting of high-titer antinuclear, anti– double-strand DNA, anti-Smith, and anti-Ro antibodies) and Raynaud phenomenon presented with persistently painful and dusky toes since wearing a new pair of boots 2 weeks previously. She also noted an increased frequency of Raynaud episodes. Her dose of nifedipine was increased (from 30 mg/d to 60 mg/d) because of the latter, and she continued her baseline regimen of prednisone (5 mg/d), mycophenolate mofetil (1500 mg, twice daily), hydroxychloroquine (400 mg/d), and indomethacin (75 mg, twice daily). Despite this, she experienced worsening pain and progressive necrosis of her toes and was hospitalized for evaluation and treatment of impending digital gangrene. On physical examination, retiform purpura was evident on the left first and second toes. There was a hemorrhagic bulla on the distal left first toe, and the left second toenail was absent, replaced by a necrotic ulcer (Figure 1). Milder purpura on a background of dusky reticulated erythema was present on the left medial sole, left third through fourth toes, and right first through fourth toes. Dorsalis pedis pulses were diminished, more so on the left foot than the right foot. Findings from arterial Doppler studies showed a complete absence of blood flow in all the digits of the left foot and in the second through fourth digits of the right foot. A biopsy specimen from the peripheral portion of the purpuric area on the left first toe revealed thrombi in the lumens of small and medium-sized blood vessels throughout the mid and deep reticular dermis (Figure 2). There was no inflammatory infiltrate or fibrin deposition in the vessel walls. Partial necrosis of the eccrine glands and the overlying epidermis was apparent. Laboratory evaluation revealed elevated anticardiolipin IgM antibody levels, which had also been elevated in laboratory testing performed 10 months prior, and presence of the lupus anticoagulant. Anticardiolipin IgG and anti2 glycoprotein I antibodies were not identified. There were no abnormalities found in the remainder of an extensive evaluation for thrombophilia, which included protein C and S levels and activity, antithrombin III activity, homocysteine levels, and testing for factor V Leiden and prothrombin gene mutations. The clinical, histologic, and laboratory findings confirmed a diagnosis of thrombotic vasculopathy second-