Warfarin-Induced Skin Necrosis

Systematic review of warfarin-induced skin necrosis case reports and secondary analysis of factors associated with mortality

OBJECTIVE

Warfarin-induced skin necrosis (WSN) is a rare (0.0.1%-0.1%) and severe adverse reaction. The clinical characteristics of this reaction and its mortality rate have not been explored in a large population. Therefore, we present the case of a Peruvian patient who developed WSN and perform a systematic review of case reports of WSN.

METHODS

A systematic search was performed using the Pubmed/Medline, Scopus, Web of Science and Embase databases. Patient clinical data were collected and extracted from every case report. Furthermore, we analysed the factors associated with mortality because of WSN using the Poisson regression model with robust variations, obtaining risk ratios (RR) and their respective confidence intervals (95% CI).

RESULTS

We identified 90 case reports that included a total of 111 patients with WSN (mean age 52.5 years), 20.72% of whom died of complications because of WSN. Being male (RR: 2.87; 95% CI 1.21-6.83) and having three or more affected regions (RR: 6.81; 95% CI 2.62-17.74) were associated with an increased risk of death caused by WSN.

CONCLUSION

This systematic review identified 90 case reports of WSN with three or more affected body regions. Male sex was associated with an increased risk of death. Further studies are needed to analyse and confirm these results.

Warfarin-induced major unilateral breast necrosis in a patient with antiphospholipid syndrome: A case report

•

Warfarin rarely causes necrosis, and antiphospholipid syndrome is a rarer cause of skin necrosis. Physicians should consider both conditions in the aetiology of skin necrosis.

•

Management should involve stopping warfarin treatment, administering alternative medications, taking a good history, and performing proper examination, investigation, and wound management with dressings or operation using a multidisciplinary team.

•

Wound management depends on the patient’s medical condition and considers the reconstructive ladder.

Introduction

Warfarin-induced necrosis is a rare complication associated with the use of warfarin in addition to antiphospholipid syndrome.

Case presentation

A 50-year-old female patient with a known case of antiphospholipid syndrome started warfarin treatment for ischaemic changes in her toes and subsequently experienced warfarin-induced necrosis in her left breast. Then, warfarin treatment was suspended, and she was started on enoxaparin. Debridement was performed, and a skin graft was applied without complications.

Discussion

Skin necrosis has many differential diagnoses, and physicians must take a proper history and perform a physical examination with proper investigations involving a multidisciplinary team, including plastic surgery, haematology, internal medicine, and wound care specialists. Plastic surgery offers many options for reconstruction depending on the patient’s medical condition, the size of the wound and the location following the reconstructive ladder.

Conclusion

This case report presents a rare complication of warfarin in the context of antiphospholipid syndrome and describes the management of unilateral breast necrosis. Physicians should be highly suspicious of this condition in patients with skin necrosis who were administered warfarin or have antiphospholipid syndrome.

Venous thromboembolism prophylaxis using the Caprini score

Venous thromboembolism (VTE) including pulmonary embolism (PE) and deep vein thrombosis (DVT) is one of the leading causes of preventable cardiovascular disease in the United States (US) and is the number one preventable cause of death following a surgical procedure. Post-operative VTE is associated with multiple short and long-term complications. We will focus on reviewing the many faces of VTE in detail as they represent common challenging scenarios in clinical practice.

Cutaneous Drug Reactions in the Elderly

Cutaneous adverse drug reactions comprise a significant proportion of all adverse drug reactions. They may mimic other dermatologic or systemic illnesses and may cause significant morbidity or mortality. Seven morphologic groups encompass the most commonly encountered cutaneous drug reaction syndromes: exanthematous (maculopapular), dermatitic/eczematous, urticarial, pustular, blistering, purpuric, and erythrodermic. Drug reactions may have significant downstream consequences for the older individual.

Acute Cutaneous Necrosis: A Guide to Early Diagnosis and Treatment

Acute cutaneous necrosis is characterised by a wide range of aetiologies and is associated with significant morbidity and mortality, warranting complex considerations in management. Early recognition is imperative in diagnosis and management of sudden gangrenous changes in the skin. This review discusses major causes of cutaneous necrosis, examines the need for early assessment, and integrates techniques related to diagnosis and management. The literature, available via PubMed, on acute cutaneous necrotic syndromes was reviewed to summarise causes and synthesise appropriate treatment strategies to create a clinician’s guide in the early diagnosis and management of acute cutaneous necrosis. Highlighted in this article are key features associated with common causes of acute cutaneous necrosis: warfarin-induced skin necrosis, heparin-induced skin necrosis, calciphylaxis, pyoderma gangrenosum, embolic phenomena, purpura fulminans, brown recluse spider bite, necrotising fasciitis, ecthyma gangrenosum, antiphospholipid syndrome, hypergammaglobulinemia, and cryoglobulinemia. This review serves to increase recognition of these serious pathologies and complications, allowing for prompt diagnosis and swift limb- or life-saving management.

Warfarin-Induced Skin Necrosis: A Case Report

Warfarin-induced skin necrosis is an unusual complication of anticoagulation therapy associated with high morbidity. A patient is presented who had protein C deficiency and in whom this complication developed twice within a short time as a result of delayed diagnosis. Early recognition of this syndrome has important implications in the treatment of such patients and may reduce the severity of complications.

Dabigatran in the Treatment of Warfarin-Induced Skin Necrosis: A New Hope

Warfarin-induced skin necrosis is an infrequent and well-recognized complication of warfarin treatment. The incidence was estimated between 0.01% and 0.1% whereas a paradoxal prothrombotic state that arises from warfarin therapy seems to be responsible for this life-threatening disease. To the best of our knowledge we present the first case of an old woman diagnosed with warfarin-induced skin necrosis, in whom novel oral anticoagulants and extensive surgical debridement were combined safely with excellent results.

Warfarin-induced skin necrosis

Warfarin-induced skin necrosis is an infrequent complication occurring in individuals under warfarin treatment who have a thrombophilic history or after administration of large loading doses of warfarin particularly without simultaneous initial use of heparin. A 62-year-old lady developed skin necrosis 4 days after initiating warfarin therapy of 5 mg daily without initial co-administration of heparin. The patient had a normal clotting profile. Skin necrosis progressed to eschar formation after cessation of warfarin and heparinization stopped expanding. Warfarin was reintroduced at 2 mg daily, initially together with low molecular weight heparin. Autolytic debridement of the necrotic tissue was followed by healing of the cutaneous deficit by secondary intention. Prompt diagnosis and discontinuation of warfarin are crucial for the prognosis.

Coumadin-induced skin necrosis in a 64 year-old female despite LMWH bridging therapy

Background:

Coumadin is the standard oral anticoagulant used in a variety of clinical conditions. Coumadin inhibits the vitamin-K dependent gamma-carboxylation of coagulation factors II, VII, IX, X and the anticoagulant proteins C and S. Rarely, skin necrosis occurs when the resultant initial procoagulant state in the first few days of starting coumadin leads to thrombosis and formation of blood clots tin the dermal capillaries. This in turn causes skin necrosis due to interruption in blood supply to the skin.

Case Report:

We are presenting the case of a 64 year-old female admitted for acute respiratory distress secondary to newly-diagnosed pulmonary embolism. The patient was started on therapeutic doses of low molecular weight heparin (LMWH) and coumadin. After 5 days of treatment, the patient started complaining of pain and numbness in both upper extremities. Overnight, this rapidly progressed to manifest hemorrhagic bullae with necrotic areas. This was immediately recognized as coumadin-induced skin necrosis. Coumadin was stopped immediately. Vitamin K was administered and local wound care was provided. Therapeutic LMWH was continued. The skin lesions began to show improvement after 3 days.

Conclusions:

In coumadin-induced skin necrosis, the patient initially presents with pain and erythema, followed by petechial lesions which progress to become purpuric. Hemorrhagic bullae with necrosis and eschar formation may soon develop. Once it is suspected, coumadin should be stopped and the patient should be given Vitamin K and FFP to reverse the effects of coumadin.

Necrose cutânea induzida por antagonistas da vitamina K

Os anticoagulantes orais que atuam através do antagonismo à vitamina K são utilizados na prática clínica há muito tempo, porém ainda há dificuldades no seu manejo e na condução das complicações. Entre as complicações, as mais conhecidas são os transtornos hemorrágicos, mas outras também devem ser reconhecidas, tais como a necrose induzida por varfarina. Esta é uma grave, porém rara complicação, cuja fisiopatologia é ainda obscura e cujas causas são indefinidas. Dentre as possíveis causas, as mais prováveis são a deficiência de proteína C e de proteína S, reações de hipersensibilidade e deficiência de fator VII. Há maior incidência desta complicação entre mulheres de meia-idade, acometendo preferencialmente mamas e glúteos. As medidas mais importantes para o tratamento são: suspensão imediata da droga, uso de heparina não fracionada ou de baixo peso molecular em doses terapêuticas, emprego da vitamina K e, eventualmente, infusão de plasma fresco congelado ou de proteína C ativada recombinante.

Atypical ischemic lower extremity ulcerations: a differential diagnosis

Severe peripheral artery disease (PAD) is the predominant cause of ischemic ulcerations involving the lower extremities. PAD-associated ulcerations are typically distally located involving the feet, toes, and sometimes the calves. In contradistinction, atypical ischemic ulcerations of the lower extremity are often non-atherosclerotic in etiology, involve the proximal leg (thigh/buttocks), can evolve despite palpable distal pulses, and may coexist with other cutaneous aberrations (e.g. macules, purpura, nodules, and livedo reticularis). A differential diagnosis of atypical ischemic ulcerations involving the legs is presented.

Atypical warfarin-induced skin necrosis

Warfarin-induced skin necrosis (WISN) is a disorder of unclear etiology that predominantly affects obese women. Although WISN typically occurs within the first 10 days of warfarin therapy, some patients develop the complication several years after warfarin exposure. We describe the case of a 43-year-old Caucasian woman with a history of recurrent thromboembolic disorders, protein S deficiency, and multiple exposures to warfarin who came to the emergency room with complaints of worsening dermatitis that had progressed over a 15-hour period. Examination revealed multiple, diffuse "lace-like" erythematous eruptions with superimposed lesions that were tender, ulcerated, and crusted. A biopsy was performed, and histopathologic findings were consistent with WISN. Based on the Naranjo adverse drug reaction probability scale, a probable causal relationship existed between warfarin and skin necrosis in this patient. Since treatment is generally supportive, prompt and prudent evaluation of suspicious skin lesions is necessary to prevent the serious sequelae associated with WISN.

Dermatotoxicity of epicutaneously applied anticoagulant warfarin

Dermatotoxic effects of epicutaneous application of a first-generation anticoagulant, warfarin (WF) were examined in rats. Selected parameters of skin activity were determined 24h following warfarin application, including metabolic viability of skin explants, some aspects of oxidative activity in skin tissue homogenates and inflammatory/immune relevant activity of epidermal cells from warfarin-treated skin. No changes in skin metabolic viability (MTT reduction) were noted ex vivo following WF application, suggesting the absence of immediate toxicity for skin. In contrast, increased formation of malondialdehyde (MDA), with a decrease in protein and non-protein thiols in homogenates of warfarin-treated skin was demonstrated, pointing to prooxidant activity in warfarin-treated skin. Increased costimulatory activity of epidermal cells isolated from warfarin-exposed skin in Con-A-stimulated T-cell activation/proliferation assay was noted, reflecting proinflammatory and immune-modulating capacity of warfarin for epidermis. No evident differences in skin histology between control and warfarin-treated skin were found at that time point, while striking changes in tissue integrity, cellularity and appearance 72 h following WF application were noted. The observed histological picture probably reflects a regenerative/inflammatory program related to oxidant/inflammation-type warfarin-evoked injury to the skin. Presented data demonstrate the potential of epicutaneously applied warfarin to modulate local skin activity in rats.

Transition to an oral anticoagulant in patients with heparin-induced thrombocytopenia

Recommendations for transitioning from therapy with heparin or a low-molecular-weight heparin preparation to therapy with an oral anticoagulant in patients with acute venous or arterial thromboembolism have undergone several changes during the last two decades. Physicians are now comfortable with beginning treatment with an oral anticoagulant once the diagnosis is confirmed, and loading doses are no longer considered to be necessary. Exceptions to early transition may be necessary in patients with an extensive iliofemoral or axillary-subclavian vein thrombosis or pulmonary embolism where thrombolytic agents may be indicated, or in individuals who require surgery or other invasive procedures, or if there are concerns about bleeding. The avoidance of early transition to oral anticoagulants in patients with acute heparin-induced thrombocytopenia also has been advised because of the potential for further thrombotic complications, including venous limb gangrene and warfarin-induced skin necrosis.

Cutaneous necrosis induced by acenocoumarol

Cutaneous necrosis is an infrequent but well-documented complication of oral anticoagulants. In the pathogenesis of cutaneous necrosis induced by oral anticoagulants recent hypotheses favour the combined role of local factors and a transient unbalance of coagulation mechanisms leading to an hypercoagulable state. There exists a genetic factor that determines a decreased level of two vitamin-K dependent glycoproteins, namely protein C and protein S. We present the case of an obese woman that developed an extensive cutaneous necrosis while receiving acenocoumarol for a deep venous thrombosis. She had an heterozygous deficit for protein C. The histopathologic findings of vessel thrombi and red blood cell extravasation were consistent with the clinical picture. A biopsy specimen taken from an initial lesion disclosed images of leucocytoclastic vasculitis. We reviewed the literature focusing on the pathogenesis and the histopathology of the disease.

Immunotoxicity of epicutaneously applied anticoagulant rodenticide warfarin: evaluation by contact hypersensitivity to DNCB in rats

The immunotoxicity of epicutaneously administered anticoagulant rodenticide warfarin (WF) was examined in this work by using experimental contact hypersensitivity (CHS) reaction to hapten dinitrochlorobenzene (DNCB). WF (0.05 and 0.5 mg/kg) administration 24 h before the induction of CHS does not change expression of CHS evaluated by ear swelling assay. Regional draining lymph node response during sensitization phase was characterized by decreased cellularity but increased spontaneous and IL-2 stimulated proliferation of draining lymph node cells (DLC). No changes in IL-2 production and in numbers of CD25(+) cells were noted and even decreased proliferative index (ratio of IL-2 stimulated to unstimulated DLC proliferation) was detected. Increase in granulocyte activity (MTT reduction and adhesion to plastic) was noted following application of WF solely with further increase following subsequent application of DNCB, when granulocyte activation (NBT reduction) was noted also. Access of WF into general circulation might be responsible for observed changes, what was supported by ex vivo changes in DLC and granulocyte functions assessed before initiation of sensitization and by in vitro effect of exogenous WF as well. Differential effects of WF on lymphocytes and granulocytes noted in this study highlight the need for simultaneous testing of both cell type activity what might constitute a more integrated approach in immunotoxicity studies.

Warfarin-induced skin necrosis associated with acquired protein C deficiency

A 36-year-old woman developed skin necrosis of the inner thighs following the re-introduction of warfarin after a laparoscopic cholecystectomy. She had a history of liver disease and cardiomyopathy and was on warfarin for 10 years. Warfarin-induced skin necrosis secondary to protein C deficiency was diagnosed. Although warfarin was ceased immediately, the prothrombin time measurements remained prolonged and warfarin levels remained therapeutic. Our patient, who had attached great significance to warfarin therapy, had continued the ingestion of warfarin despite our advice. She required three surgical debridements. Protein C levels, as measured 1 year later, were within normal limits, confirming the transient nature of the acquired deficiency during the acute event. This is the second reported case of warfarin necrosis associated with acquired protein C deficiency.

Fatal warfarin-induced skin necrosis after total hip arthroplasty

Skin necrosis associated with warfarin anticoagulation is a rare but serious complication. Few cases of warfarin-induced skin necrosis are found in the orthopaedic literature. We report a fatal case of warfarin-induced skin necrosis after total hip arthroplasty.

Adverse dermatologic effects of cardiovascular drug therapy: part III

Cardiovascular disease is common, affecting an increasing number of persons as the population ages. To combat this growing health problem, physicians use a multitude of medications in the treatment of their patients. Although pharmacologic therapy greatly enhances quality of life for a majority of patients, there is always the potential for an unfavorable reaction. For example, cardiovascular drugs can induce a vast array of adverse dermatologic responses. This article reviews the various cutaneous reaction patterns that can occur as a result of treatment with vasodilators and other antihypertensive drugs, anticoagulants and antiplatelet drugs, thrombolytic agents, and lipid-lowering agents.

Localized cutaneous necrosis associated with the antiphospholipid syndrome

A 34-year-old woman with systemic lupus erythematosus and high titres of antiphospholipid antibodies was admitted to hospital suffering a viral illness but developed haemorrhagic and necrotic areas on the neck and anterior chest 7 days following cessation of warfarin. Anticoagulation had been initiated following a retinal vein thrombosis, but was ceased on day 4 of admission when she was found to be excessively anticoagulated (international normalized ratio (INR) > 10). However, at the time of developing the cutaneous lesions, the INR was sub-therapeutic. Histology of a skin biopsy from the neck revealed thrombosis of upper dermal blood vessels without vasculitis, consistent with antiphospholipid antibody-related skin necrosis. This case illustrates one of the cutaneous features that can occur in patients with elevated titres of antiphospholipid antibodies and the importance of closely monitoring anticoagulation in such patients.

A meta-analysis of thromboembolic prophylaxis in total knee arthroplasty

Deep venous thrombosis (DVT) is common in total knee arthroplasty (TKA). Because of the rarity of the most serious outcomes, most randomized controlled trials lack the power to analyze these outcomes. A meta-analysis was performed for agents used in DVT prophylaxis in TKA employing a Medline literature search. Study inclusion criteria were randomized controlled trials comparing prophylactic agents in elective TKA with mandatory screening for DVT by venography. Fourteen studies (3,482 patients) met inclusion criteria. For total DVT, all agents except dextran and aspirin protected significantly better than placebo (P < .0001). For proximal DVT rates, low-molecular-weight heparin was significantly better than warfarin (P = .0002). There was a trend that aspirin was better than warfarin (P = .0106). No significant difference was found for symptomatic pulmonary embolism, fatal pulmonary embolism, major hemorrhage, or total mortality.

Prothrombotic phenotype of protein Z deficiency

Protein Z (PZ) is a vitamin K-dependent plasma protein whose function has been uncertain. The structure of PZ is very similar to that of the coagulation-related factors VII, IX, and X and PC, but PZ differs from these other proteins in that it is not the zymogen of a serine protease. We have shown recently that PZ forms a calcium ion-dependent complex with activated factor X at phospholipid surfaces and that this interaction leads to the inhibition of activated factor X activity through, in part, the action of a previously unidentified plasma protein named PZ-dependent protease inhibitor. Herein, we report that the presence of PZ dampens the coagulation response in human plasma and that concomitant PZ deficiency dramatically increases the severity of the prothrombotic phenotype of factor V(Leiden) mice. The results indicate that PZ plays a physiologically important role in the regulation of coagulation.

Warfarin induced skin necrosis

BACKGROUND

Warfarin induced skin necrosis is a rare complication with a prevalence of 0.01-0.1 per cent. It was first described in 1943.

METHODS

A literature review was undertaken using Medline; all relevant papers on this rare compli-cation of warfarin therapy were used.

RESULTS

There are several adverse skin manifestations associated with the use of oral anticoagulants, ranging from ecchymoses and purpura, haemorrhagic necrosis, maculopapular vesicular urticarial eruptions to purple toes. This article concentrates mainly on warfarin induced skin necrosis. The syndrome typically occurs during the first few days of warfarin therapy, often in association with the administration of a large initial loading dose of the drug. Although the precise nature of the disease is still unknown, advances in knowledge about protein C, protein S and antithrombin III anticoagulant pathways have led to a better understanding of the mechanisms involved in pathogenesis. Differential diagnosis between warfarin induced skin necrosis and necrotizing fasciitis, venous gangrene and other causes of skin necrosis may be difficult; the disease may also be confused with other dermatological entities.

CONCLUSION

Warfarin induced skin necrosis, while rare, is an important complication. All surgeons should be aware of its existence.

Multicentric warfarin-induced skin necrosis complicating heparin-induced thrombocytopenia

Two patients developed catastrophic multicentric skin necrosis while receiving warfarin to treat venous thromboembolism complicated by immune-mediated heparin-induced thrombocytopenia (HIT). Patient 1 developed skin necrosis involving the breasts, thighs, and face, as well as venous limb gangrene and bilateral hemorrhagic necrosis of the adrenal glands, resulting in death. The second patient developed bilateral mammary necrosis necessitating mastectomies, as well as skin necrosis involving the thigh. Neither patient had an identifiable hypercoagulable syndrome, other than HIT. HIT may represent a risk factor for the development of multicentric warfarin-induced skin necrosis (WISN).

Anticoagulant-induced skin necrosis in a patient with hereditary deficiency of protein S

Skin necrosis is a rare but debilitating complication of treatment with vitamin K antagonist anticoagulants such as warfarin. A clinically similar syndrome has been reported less frequently with heparin therapy. We recently managed a thirty-year-old female patient who developed skin necrosis on her left lower extremity while on warfarin for postpartum DVT. The lesions started to develop 48 hr after stopping heparin therapy. Discontinuation of warfarin and reinstitution of heparin was complicated by a rapid decrease in platelet count consistent with heparin-induced thrombocytopenia (HIT) and its associated risk of platelet activation and thrombosis. The diagnosis was supported by the identification of antibodies against heparin/platelet factor 4 complexes in the patient's serum. The platelet count recovered and the patient improved after switching to therapy with the heparinoid danaparoid. Evaluation for a hypercoagulable state revealed a partial deficiency of protein S, a condition that previously was identified in two of her family members. It is not clear if this patient suffered from warfarin-induced skin necrosis, a manifestation of heparin-mediated platelet activation, or a complex condition in which both drugs contributed. HIT may affect 1-3% of patients who receive unfractionated heparin, and this case raises the possibility that heparin may contribute to, or cause, some episodes of skin necrosis attributed to warfarin. Because many patients who develop warfarin-induced skin necrosis have been treated initially with heparin, it would seem prudent to consider HIT in these situations.

Warfarin-induced skin necrosis

Skin necrosis is an uncommon complication of warfarin (Coumadin; Dupont Pharma, Wilmington, DE) therapy. The presentation may mimic other disorders. This article reports a case of a 72-year-old woman who presented to the emergency department complaining of swelling and ecchymosis to her left breast and right foot. The patient had been hospitalized for coronary artery bypass grafting, and had been discharged from the hospital earlier that day. This article reviews the pathophysiology and clinical features of warfarin-induced skin necrosis.

Late-onset warfarin-induced skin necrosis: case report and review of the literature

Warfarin-induced skin necrosis is a rare complication of therapy with warfarin or other coumarin derivatives. When it occurs it usually appears 3 to 6 days after initiation of therapy and almost always between days 1 and 10. We report a case of late-onset (16 days after initiation of therapy) warfarin-induced skin necrosis and review the literature on this rarely reported variant of warfarin-induced skin necrosis. The skin lesion in our patient was not associated with either deficiency of protein C or resistance to activated protein C.

Cutaneous reactions to recombinant human interferon beta-1b: the clinical and histologic spectrum

BACKGROUND

Recombinant human interferon beta-1b has been recently approved for the treatment of multiple sclerosis. A significant proportion of patients treated with this medication experienced cutaneous reactions.

OBJECTIVE

We describe the clinical and histologic features of cutaneous reactions to recombinant human interferon beta-1b.

METHODS

Consecutive patients with cutaneous reactions to recombinant interferon beta-1b were evaluated clinically and by biopsy.

RESULTS

Clinical lesions varied from subtle uninflamed sclerotic dermal plaques to erythematous plaques to cutaneous ulcers at injection sites. The nonsclerotic lesions were frequently painful. The firm plaques showed fibrosis histologically, whereas nonsclerotic inflammatory lesions demonstrated a consistent pattern of vascular thrombosis. Hematologic evaluation demonstrated platelet activation in most patients with inflammatory lesions, a feature also noted before interferon treatment in some patients.

CONCLUSION

Therapy with recombinant interferon beta-1b is associated with a spectrum of cutaneous reactions and vascular thrombosis.

Necrotizing skin lesions induced by low-molecular-weight heparin after total knee arthroplasty

We report the unusual complication of focal necrotizing skin lesions accompanied by moderate thrombocytopenia in a female patient undergoing thromboprophylaxis with low-molecular-weight heparin after total knee arthroplasty. Heparin-induced thrombocytopenia was suspected and confirmed using the heparin-induced platelet activation assay. The skin lesions improved gradually after the discontinuation of heparin application. In addition to the description of this exceptionally rare adverse effect of low-molecular-weight heparin, a brief discussion of previously reported cases is provided.

Warfarin-Related Skin Necrosis

Skin and soft tissue necrosis may be an unexpected and unpredictable consequence of warfarin therapy, occurring in 0.01% to 0.1% of patients receiving the drug. Classically, the archetypal patient is female, middle-aged or older, and the area of necrosis occurs in areas of abundant fat, such as breast, thigh or abdomen. The onset begins three to 10 days after commencing therapy. Two cases of warfarin-related skin necrosis are presented. One is a classical abdominal presentation. The other is a much rarer presentation of warfarin necrosis affecting the hand. The implications of the variable presentations in terms of pathophysiology and treatment strategies are discussed.

Hematologic disorders associated with ischemic stroke

Hematological disorders underlie a small proportion of all ischemic strokes. The association of these coagulation abnormalities with ischemic stroke is not always clear. The etiology of stroke still remains uncertain in a large number of cases and proper screening for coagulation abnormalities and the discovery of new coagulation disorders will probably increase the rate of strokes attributable to these causes. Since large case-control studies with unselected and consecutive stroke patients from different ethnic origins have not yet been performed to determine the role of coagulation abnormalities in ischemic stroke, our knowledge is dependent on case reports and small series of mostly younger patients. Extensive hematologic evaluation of unselected stroke patients will likely yield little useful information and be too expensive. Every stroke patients needs a careful evaluation, and in selected cases, this should include coagulation parameters. Patients with unexplained strokes after a careful evaluation, previous thrombotic episodes, or a positive family history for thrombosis, are good candidates for further coagulation studies. As long as the hypercoagulable state persists, both arterial and venous thromboembolic recurrences can be expected. Many of these patients may benefit from anticoagulants. In patients with hereditary coagulation disorders, studies should be extended to close relatives. Since some coagulation tests are fairly expensive, provide only equivocal data, and are not widely available, we advise a step-by-step approach starting with the patient and family history.

Outpatient anticoagulation issues for the primary care physician

Increasingly, primary care providers are caring for patients who require anticoagulation. In this article the indications for, complications of, and methods of dosing and monitoring warfarin in the outpatient setting are reviewed. Heparin use among ambulatory patients also is discussed.