Differentials
Normal response to cold
SIGNS / SYMPTOMS
Normal hands can be mottled in cold. RP has classic pallor that is well demarcated.
INVESTIGATIONS
No differentiating tests.
Cyanosis/cryoglobulinemia
SIGNS / SYMPTOMS
Blue digits in cold but no distal digital pallor.
INVESTIGATIONS
Detection of circulating cryoglobulins.
Chilblains (perniosis)
SIGNS / SYMPTOMS
Symptoms include pruritus, erythema, and ulceration.
An acute response to cold temperatures but can be chronic.
INVESTIGATIONS
No differentiating tests.
Frostbite
Acrocyanosis
SIGNS / SYMPTOMS
There is no ischemia (no pallor in this condition), which is characterized by nonparoxysmal, in most cases persistent, painless bluish-red symmetric discolorations of the hands and often the feet. History with lack of pallor (no well-demarcated white color change).[8]
INVESTIGATIONS
No differentiating tests.
Erythromelalgia
SIGNS / SYMPTOMS
Usually provoked by heat.
Characterized by painful red extremities, burning, and increased skin temperature of affected area.[8]
INVESTIGATIONS
Thrombocytosis may be underlying cause.
Livedo reticularis
SIGNS / SYMPTOMS
Lacy purple appearance of skin at extremities.
Venous blood flow sluggish.
Usually found on legs.
INVESTIGATIONS
May be positive for antiphospholipid antibodies (e.g., anticardiolipin antibodies, lupus anticoagulant).
Carpal tunnel syndrome
SIGNS / SYMPTOMS
Numbness and tingling of fingertips, with no distal digital pallor.
Associated conditions may be present: pregnancy, hypothyroidism, diabetes, or rheumatoid arthritis.
Positive Tinel or Phalen test in carpal tunnel syndrome. Lack of color change in carpal tunnel syndrome.
INVESTIGATIONS
Nerve conduction studies: focal slowing of conduction velocity in the median sensory nerves across the carpal tunnel (necessary only if symptoms are severe or there is wasting of the thenar eminence).
Elevated thyroid-stimulating hormone, blood glucose, and serum abnormalities of other associated conditions may be present.
Cervical rib or other subclavian compression
SIGNS / SYMPTOMS
May develop RP, but ischemia is often positional with the arm above the head.
INVESTIGATIONS
CXR may demonstrate cervical rib. Routine screening of mild RP would not require this investigation, as it would be performed only if there was a high index of suspicion.
Subclavian steal syndrome
SIGNS / SYMPTOMS
Symptoms/signs of peripheral ischemia usually present unilaterally.
Dizziness, syncope, and vertigo common.
INVESTIGATIONS
Duplex ultrasonography demonstrates retrograde blood flow and occlusive lesions of vascular architecture.
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