A Case Report and Review of the
Dr Mohamad Taha Yousuf
Consultant of Vascular Surgery
Mataria Teaching Hospital
Warfarin is the standard oral anticoagulant used in a
variety of clinical conditions. Warfarin inhibits the
vitamin-K dependent gamma-carboxylation of
coagulation factors II, VII, IX, X and the anticoagulant
proteins C and S.
Rarely (0.01 to 0.1 percent of warfarin-treated patients),
skin necrosis occurs when the resultant initial
procoagulant state in the first few days of starting
Warfarin leads to thrombosis in the dermal capillaries,
leading to skin necrosis.
Kumar M, Abrina V, Chittimireddy S. Coumadin-induced skin necrosis in a 64 year-old female despite LMWH
bridging therapy. Am J Case Rep. 2012;13:157-159.
Skin necrosis affects areas of the body with a high fat content, such as
breasts, thighs, buttocks, and abdomen. It is more common in females.
Onset of skin changes may begin from day one to day ten, with a peak
incidence on days three to seven after initiating Warfarin.
The condition is most often unilateral, but 30 percent of cases occur
bilaterally with multiple lesions.
Early recognition of this complication is very important because a delay in
the diagnosis may lead to serious complications such as limb amputation.
Brooks LW, Blais FX. Coumadin-induced skin necrosis. J Am Osteopath Assoc 1991;91(6):601-5.
Eby CS. Warfarin-induced skin necrosis. Hematol Oncol Clin North Am 1993;7(6):1291-300.
Our patient is a 52 year old Egyptian female with PMH of
diabetes and hypertension with a history of
a cerebrovascular accident 2 months ago with residual
aphasia and bulbar symptoms.
The patient presented to the emergency department with a
few days history of left lower limb edema.
Duplex ultrasound revealed left ileo-femoral DVT.
The patient was not admitted due to family refusal, so
Tinzaparin 0.7 ml once daily s.c. and Warfarin 5 mg tab. once
daily were prescribed with follow up at outpatient
department to check her INR after 1 week.
The patient returned to the emergency department after 8 days
by disturbed conscious level (GCS 10/15), chest infection and
urinary tract infection.
The left lower limb was swollen but less than before with
ecchymosis in the left thigh and left foot with blackish
The patient was admitted in the medical ICU.
CBC showed leukocytosis of 34000, severe anemia with
a hemoglobin of 6.6 mg/dL, and thrombocytopenia with
a platelet count 111000.
INR was 5.1 Creat. 1.2
Warfarin-induced skin necrosis was suspected based on presentation, time
since initiation of warfarin therapy and supratherapeutic INR.
Warfarin was stopped.
The patient received vit. K 10 mg I.V. amp.,2 units PRBCs, 4 units FFP and
broad spectrum antibiotic.
Subsequent lab. results were as follows:-
2nd day 3rd day 4th day 5th day
Hb 7.7 8.3 8.6 10.2
WBCs 30400 28900 27200 23100
Platelets 152000 153000 182000 207000
INR 12.9 9.1 5 3.2
• Duplex ultrasound revealed subacute left ileo-
• Abdominal ultrasound revealed fatty liver and
grade II nephropathy.
We put a plan of local wound care, waiting for
improvement of the general condition of the patient
for the definitive care.
After improvement of the INR, Fondaparinux 2.5 mg
once daily was started.
Unfortunately the patient died suddenly without
any surgical intervention in the 6th day of
The clinical use of the coumarin anticoagulants began with the
discovery of an anticoagulant substance formed in spoiled
sweet clover silage which caused hemorrhagic disease in cattle.
At the behest of local farmers, a chemist at the University of
Wisconsin identified the toxic agent as bishydroxycoumarin.
A synthesized derivative, dicumarol and its congeners, most
notably warfarin (Wisconsin Alumni Research Foundation, with
"arin" from coumarin added; were initially used as
Warfarin (Bristol-Myers Squibb, New York, NY) was first introduced in
1941 and now it is a frequently used oral anticoagulant that is approved
by the US Food and Drug Administration (FDA) in 1955 for the treatment
and prevention of various medical conditions.
Warfarin inhibits the vitamin-K dependent gammam carboxylation of
coagulation factors II, VII, IX, X and the anticoagulant proteins C and S.
The blockade results in incomplete coagulation factor molecules that are
The protein carboxylation reaction is coupled to the oxidation of vitamin
K. The vitamin must then be reduced to reactivate it. Warfarin prevents
reductive metabolism of the inactive vitamin K epoxide back to its active
After starting Warfarin therapy, there is a delay in its action. Its
anticoagulant effect results from a balance between partially inhibited
synthesis and unaltered degradation of the four vitamin K dependent
The resulting inhibition of coagulation is dependent on their degradation
half-lives in the circulation. These half-lives are 6, 24, 40, and 60 hours for
factors VII, IX, X, and II, respectively.
The initial procoagulant effect of Warfarin
Half the activated Protein C disappears within 6 hours (its half-life). So,
Protein C runs out during the first few days of warfarin therapy, before
Factor X and II disappear, which have half-lives of 2-3 days. In some
circumstances this leads to excessive clotting.
Warfarin-induced skin necrosis was described by Flood and
colleagues who reported a case of a gangrenous breast but
erroneously believed it was due to an underlying coagulopathy and
not the drug therapy.
In 1954, Verhagen described a series of 13 patients on dicumarol who
developed necrosis, but he incorrectly suggested the necrosis was
associated with the underlying disease being treated when in fact it
was complicated by
a thrombosis and dicumarol therapy.
In 1961 Kipen first correctly ascribed the gangrenous skin changes to
Flood EP, Redish MH, Bociek S, et al. Thrombophlebitis migrans disseminata. NY State J Med 1943;43:1121-4.
Berkompas DC. Coumadin skin necrosis in a patient with a free Protein S deficiency. India Med 1991;84(11):788-91
Verhagen H. Necrosis of skin and underlying tissues during anticoagulant therapy with dicumarol Acta Medica Scandinavica 1954;148:453.
Kipen CS. Gangrene of the breast: A complication of anticoagulant therapy. N Engl J Med 1961;265:638-40.
What are the clinical features?
The condition remains a major diagnostic and therapeutic
The first sign is usually parathesia, pain and purpura ,
which over a few days becomes bluish-black with a red
Hemorrhagic bullae and full thickness skin necrosis
Who is affected by warfarin necrosis?
Warfarin induced skin necrosis is more common in women
than men. It usually occurs between the age of 50 and 70
years. It is more common in obese patients and
Warfarin induced skin necrosis is more likely if warfarin is
given without heparin or if a higher loading dose of
warfarin is given in the first day or two of treatment.
WISN is a complication of the drug therapy rather than
the result of simple over-anticoagulation.
Coumadin-Induced Skin Necrosis Janice M. Beitz, PhD, RN, CS, CNOR, CWOCN
What are the risk factors?
Inherited deficiency of Protein C, Protein S or Factor V
The exact aetiology of Warfarin-induced skin necrosis is still
unknown, but is often associated with a hypercoagulable state.
Protein C or protein S deficiencies have been reported in
patients with Warfarin-induced skin necrosis as well as in those
with Factor V Leiden, mutation of the prothrombin gene, lupus
anticoagulants and antiphospholipid syndrome.
ANDERSON DR, BRILL-EDWARDS P, WALKER I:. Haemostasis (1992) 22:124-128.
The pathogenesis is believed to be secondary to
a more rapid initial reduction in blood levels of vitamin K-
dependent anticoagulants (proteins C and S) than the
procoagulants (factors II, IX, X) during the warfarin
anticoagulation, this would paradoxically render a temporary
hypercoagulable especially In those patients already deficient
in the natural anticoagulants, i.e., protein C, protein S and
The transient hypercoagulability leads to local thrombotic
occlusions in the small vessels of the skin followed by skin
ROSE VL, KWAAN HC, WILLIAMSON K, HOPPENSTEADT D, WALENGA J, FAREED J:
Am. J. Clin. Pathol. (1986) 86:653-635.
The diagnosis of warfarin induced skin necrosis is made clinically.
Clinical history and cutaneous distribution may be of major
assistance in distinguishing WISN from other conditions,
because WISN lesions are difficult to distinguish histologically
Biopsy results suggestive of WISN usually show fibrin and
thrombi in small dermal vessels with no evidence of
Blood tests for protein C and protein S levels are important to
assess the likely predisposing causes.
Comp PC, Elrod JP, Karzenski S. Warfarin-induced skin necrosis. Semin Thromb Hemost 1990;16(4):293-8.
Recognition of the population at risk is crucial.
According to The American College of Chest Physicians Guidelines, a
bridge therapy for at least 5 days and until the INR is stable and
therapeutic for at least 24 hours in patients receiving warfarin for
treatment of a DVT.
Standard or low-dose warfarin should be used instead of initial large
A clinician should be cautious when advancing the dosage of warfarin.
In high risk patients full heparinization should be
achieved before starting warfarin.
Clinicians should be aware of the syndrome and
especially attuned to patients with early complaints of
localized skin discomfort especially in the breast,
buttocks, and thighs even in the absence of overt signs.
A high level of suspicion may allow rapid reversal of
warfarin and full heparinization before the syndrome
TreatmentNo current consensus exists regarding how to best treat WISN. Current
treatment options are based on previously published case reports and
include the following:-
Immediate discontinuation of warfarin to prevent further necrosis, reversal
of warfarin effects by the administration of vitamin K and FFP or PCC.
Protein C concentrate in patients with an underlying deficiency.
Anticoagulation should be continued with a parenteral agent once
Wound care. Viegas GV. Coumadin skin necrosis: Pedal manifestations. J Am Podiatr Med Assoc 1992;82(9):463-8.
For the necrotic areas topical therapy may include use of local
antibiotics, such as silver sulfadiazine, or special dressings
including foams, special impregnated gauzes, and hydrogels.
Surgical treatment is required in more than 50 percent of cases,
with mastectomies and amputations necessary in advanced
Skin grafting may be required. Myocutaneous flaps are
sometimes needed to close large defects.
Timmons J. Dressing selection for the treatment of coumarin necrosis. Nurs Stand 2000;14(49):66-8, 70.
Miura Y, Ardenghy M, Ramasastry S, et al. Coumadin necrosis of the skin: Report of four patients. Ann Plast Surg 1996;37:332-7
Sustained anticoagulation is vital for some patients'
conditions but remains a challenge. Long-term heparin
is inconvenient and may be associated with
osteoporosis. An alternative is enoxaparin, a low-
Cases have been reported in which WISN sufferers
have been restarted on Warfarin without any further
sequelae (warfarin was started at 1 mg/day with a
very slow increase in the dose). Others have
developed signs of impending recurrence.
Jillella AP, Lutcher CL. Reinstituting warfarin in patients who develop warfarin skin necrosis. Am J Hematol 1996;52:117-9.
Development of new oral anticoagulants offers the
possibility of treating these patients effectively due to
the high thrombophilic diathesis in such patients.
After the acute event is resolved ,the patient and
family members may need to consider testing for
Protein C and S or Antithrombin deficiencies.
Arch Turk Soc Cardiol 2014;42(8):787
WISN is a rare but serious complication of Warfarin therapy,
associated with high morbidity and mortality rates, and often
requires surgical intervention.
WISN usually appears 3 - 7 days after initiating warfarin
treatment in susceptible individuals, although it may appear
It is more common in females and frequently affects areas with
abundant subcutaneous fatty tissue such as breasts, thighs, and
A bridge therapy for at least 5 days and until the INR is stable
and therapeutic is important.
Standard or low-dose warfarin should be used instead of
initial large loading-doses.
Once it is suspected, Warfarin should be stopped and the
patient should be given Vitamin K and FFP to reverse the
effects of Warfarin.
The novel anti-coagulants can be safely used in this relatively
rare but serious clinical situation.