Reversible retiform purpura: a sign of cocaine use.

quent inhalational cocaine use was admitted to hospital after presenting to the emergency department with a four-month history of intermittent painful bruises (retiform purpura) involving her arms and legs, with recent ulceration of her nasal tip, ears and cheeks (Figures 1A, 2A and 3A). Previous episodes of the retiform purpura had improved spontaneously following abstinence from inhalational cocaine use. The patient’s medical history included Parkinson disease and em physema. She had no history of venous or arterial thromboembolism, pregnancy complications or spontaneous abortions. A complete blood count showed a leukocyte count of 2.4 (normal 4.0–11.0) × 10/L, with a low absolute neutrophil count of 1.4 (normal 2.0–8.0) × 10/L, a hemoglobin level of 112 (normal 115–155) g/L and a normal platelet count of 184 (normal 150–400) × 10/L. A positive atypical perinuclear antineutrophil cytoplasmic antibody (titer > 1:640) was detected, with an elevated proteinase 3 level. Testing for anticardiolipin antibodies was positive for im munoglobulin M (level 37.3 [normal 0–20] MPU) and negative for immunoglobulin G. β2 glycoprotein I antibody and lupus anticoagulant testing was negative. International normalized ratio, partial thromboplastin time, and protein C, protein S and antithrombin levels were normal, as were the results of complement, cryoglobulin, rheumatoid factor, antinuclear antibody and extractable nuclear antigen tests. A skin biopsy showed extensive thrombotic vasculopathy without evidence of vasculitis. Results of echocardiography, blood culture and special stains on skin biopsy ruled out an underlying infectious vaso-occlusive process. The patient had been admitted to another hospital three months previously with similar but less dramatic clinical findings, also with positive anticardiolipin immunoglobulin M serology of 43.2 MPU. The lesions had improved spontaneously during the patient’s hospital stay. This previous admission had also been preceded by recent exposure to cocaine. Thus, with clinical features of cutaneous vascular necrosis and recurrence of abnormal anticardiolipin serology 12 weeks apart, a diagnosis of antiphospholipid antibody syndrome was made. The patient was given pulse intravenous steroids and subcutaneous dalteparin for anticoagulation during her course in hospital. Further, abstinence from inhalational cocaine was recommended. Despite extensive purpura at presentation suggestive of necrosis, the lesions improved, demonstrating evidence of reperfusion and re versibility (Figures 1B, 3B and 3C). In addition, neutropenia reversed spontaneously, as had been noted on her previous hospital admission. The patient was given warfarin as an outpatient and maintained a therapeutic international normalized ratio of 2.0–3.0. Despite measures to encourage abstinence from inhalational cocaine use and despite ongoing anticoagulation treatment at therapeutic levels, a third admission to hospital was required, with clinical evidence of retiform purpura of the legs (Figure 2B) and neutropenia after cocaine inhalation. Reversibility was again shown with abstinence from cocaine use. Warfarin was stopped and the patient was given dalteparin for ongoing anticoagulation therapy, but she continued to develop new skin lesions following re peated cocaine inhalation. Reinitiation of oral prednisone therapy at 20 mg/d resulted in further improvement. The unique clinical reversibility of this phenomenon on abstinence from drug use and reliable clinical recurrence with exposure to cocaine on multiple occasions is noteworthy. Competing interests: None declared.