39: Red Spots

An 81-year-old female comes to the ED for an “infection” in her leg.  She states that she had cellulitis in this leg before and worries it has come back.  She notes multiple dark red spots on her shin and the dorsum of her foot.  She denies any fever, pain or swelling.

On exam she is afebrile and her vitals are normal.  You note a unilateral non-blanching rash on her left lower leg and foot.  She also has an ecchymotic area on her heel (not shown).  There is no significant tenderness or swelling.  Her pulses are diminished, but symmetric.  The rest of her exam is unremarkable and there are no other areas of rash.

Her labs show a normal hemoglobin and WBC count, but the platelets are somewhat low at 108,000.   The metabolic panel is normal.  What other test or tests should you do?

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Answer: Venous & Arterial Duplex

DIAGNOSIS: ACUTE DVT + ARTERIAL THROMBOSIS.

I’ve never read of a DVT causing petechiae without other symptoms, but I’ve seen it twice, once with a concomitant arterial thrombosis and once without.  The second one was even more of a mystery because the rash was on the shins and was bilateral.  He also had slightly decreased platelets, which may play a contributory role.  I’ll leave it to the academics in the crowd to leave their comments below and enlighten us all.

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EXCERPT ON PETECHIAE, PURPURAE, & ECCHYMOSES

from

QUICK ESSENTIALS: EMERGENCY MEDICINE

PETECHIAE, PURPURAE, & ECCHYMOSES: 
Definitions:    <2mm = petechia, >1cm = ecchymosis, in between = purpura
Ecchymosis:    DDx: trauma, coagulopathy, platelets, von Willebrands, capnocytophyga
Petechiae:    Below nipple ĉ fever: 20% bacteremia; often start at cuffs/waist;
DDx:        “REDLIGHTS”: RMSF(see ID section), Emboli fat, Drug, DVT, Leukemia, ITP, TTP,
SBE, meninGococcus, Hemolytic Uremic Syndrome, sepsis, scurvy, cough, trauma
Purpura:    Palpable: allergic, vasculitis(see Rheum), emboli.  Ecthyma: G- rods, fungi; PT/PTT

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