History
Neonatal purpura fulminans
Neonatal purpura fulminans occurs usually in patients with a deficiency of protein C. Protein C deficiency is usually inherited in an autosomal dominant manner, with heterozygous carriers often remaining asymptomatic until later in life, when they become very susceptible to venous thromboembolism. Autosomal recessive protein C deficiency, which is caused by homozygous or compound heterozygous mutations in protein C, is less common and usually leads to a more severe form of the disease, with onset of thrombotic manifestations at birth.
Within the first 72 hours after birth, a neonate with neonatal purpura fulminans exhibits purpuric lesions over many different skin sites, including the perineal region, the flexor surface of the thighs, and abdominal skin. The skin lesions soon enlarge and become vesiculated, producing hemorrhagic bullae with subsequent necrosis and black eschar formation. The margins of the lesions become erythematous and indurated. Thrombocytopenia is often evident.
The patient may later develop signs of a urinary tract infection (UTI). (For more information on the diagnosis and treatment of UTIs, see Urinary Tract Infection, Females; and Urinary Tract Infection, Males.)
Idiopathic purpura fulminans
Most of idiopathic purpura fulminans cases occur in children, and more than 90% are preceded by infection (commonly varicella or streptococcal infection). The purpura usually begins suddenly, 7-10 days after the onset of the precipitating infection, with the development of progressively enlarging, well-demarcated purplish areas of hemorrhagic cutaneous necrosis with deranged coagulation factors. Lesions begin as erythematous macules that progress within hours to sharply defined areas of purpura.
The illness is often complicated by impaired perfusion of limbs and digits, as well as major organ dysfunction caused by thromboembolic phenomena involving the lungs, the heart, or the kidneys. [18] In some cases, patients have undetectable levels of free protein S, as well as protein C and ATIII, at the time of admission. Procoagulant and anticoagulant factors, including protein C, protein S, and ATIII, must be measured by functional assays.
Acute infectious purpura fulminans
Over time, the term purpura fulminans has come to be applied to cases of purpura fulminans that occur in the face of overwhelming sepsis (ie, sepsis-associated fulminans). The four primary features of this syndrome are as follows:
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Large purpuric skin lesions
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Fever
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Hypotension
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DIC
Meningococci in the bloodstream are generally more predisposed to cause a dysfunction of the activated protein C pathway than other bacteria are. Staphylococcus aureus has been associated with purpura fulminans with accompanying toxic shock syndrome. [19]
Physical Examination
Purpura fulminans is frequently associated with shock physiology, including tachycardia, hypotension, fever, and altered mental status. Hallmark dermatologic features of purpura fulminans include the following (see the image below):
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Nonblanching purpura
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Sharply demarcated lesions
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With advanced disease, the development of hemorrhagic bullae with overlying skin sloughing
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Possible coalescence of lesions in branching or angular patterns
With severe advanced disease, multiorgan failure manifests with widespread bleeding, stroke, liver failure, and acute respiratory failure.
Lesion associated with purpura fulminans in an adult patient. Courtesy of DermNet New Zealand.
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Lesion associated with purpura fulminans in an adult patient. Courtesy of DermNet New Zealand.
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Schistocytes (arrows) on a peripheral smear. Courtesy of Bodhit AN, Stead LG. Altered mental status and a not-so-benign rash. Case Rep Emerg Med. 2011;2011:684572.
Tables
Typical Lab Values in Acute Disseminated Intravascular Coagulation (DIC)* |
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Lab Test |
Acute DIC |
Reference Range |
Platelet count |
< 150,000/L |
150,000-450,000/L |
Fibrinogen |
>340 mg/dL |
170-340 mg/dL |
Prothrombin time (PT) |
>13 seconds |
9-13 seconds |
Activated partial thromboplastin time (aPTT) |
>35 seconds |
23-35 seconds |
D-dimer |
>250 ng/mL |
0-250 ng/mL |
