Differentials
Deep vein thrombosis
SIGNS / SYMPTOMS
Acute onset of swelling, warmth, redness, and pain that is more diffuse and can involve the whole leg. Palpable cord is not common along the course of an affected vein unless there is concomitant superficial vein thrombosis.
INVESTIGATIONS
Doppler ultrasound: thrombus in the deep venous system will confirm diagnosis.
Cellulitis
SIGNS / SYMPTOMS
Erythema is usually localized and confluent, with associated tenderness and generalized swelling. There may be associated lymphangitis or tender lymphadenopathy, which is not characteristic of superficial vein thrombosis. A palpable cord is not present with cellulitis. Systemic findings of fever, chill, and myalgias are more common with cellulitis.
INVESTIGATIONS
Doppler ultrasonography: compressible veins, absence of superficial vein thrombus.
Lymphedema
SIGNS / SYMPTOMS
Usually chronic rather than acute nonpitting edema of the extremity and involving the digits. Edema does not resolve or improve with recumbency. Involvement of feet and toes typical in lymphedema of lower extremity.
INVESTIGATIONS
Doppler ultrasonography: compressible veins, absence of superficial vein thrombus; B-mode imaging shows subcutaneous edema.
Chronic venous insufficiency
SIGNS / SYMPTOMS
Usually chronic leg swelling with associated ectatic veins, varicose veins, and skin changes that may include hyperpigmentation, stasis dermatitis, panniculitis, lipodermatosclerosis, and venous ulcers.
INVESTIGATIONS
Diagnosis is usually made on clinical exam.
Confirmation on Doppler ultrasonography: can show valvular incompetence and chronic venous obstruction and absence of acute thrombus.
Erythema nodosum
SIGNS / SYMPTOMS
Most common form of panniculitis, usually consisting of raised painful bilateral tender lesions that are frequently located over both shins. There is no palpable cord.
INVESTIGATIONS
Skin biopsy: septal panniculitis.
Cutaneous polyarteritis nodosa
SIGNS / SYMPTOMS
A form of vasculitis consisting of nodules of a bright red to blue color that follow the course of arteries. Usually bilateral and become confluent to form painful subcutaneous plaques.
INVESTIGATIONS
Skin biopsy: necrotizing vasculitis of the arteries.
Insect stings or bites
SIGNS / SYMPTOMS
A recent history of an insect bite or sting is typically given. Swelling and redness usually extend over a large area and do not follow the course of a vein. There may be associated pruritus.
INVESTIGATIONS
Diagnosis usually made on clinical exam.
Doppler ultrasonography: negative for superficial vein thrombus.
Tendonitis
SIGNS / SYMPTOMS
Usually pain, mild swelling, and warmth in the area of a tendon (e.g., Achilles', patellar). Pain increases with movement of affected joint, and a tendon friction rub may be palpable. Pain is worse during and after activity, and the tendon and joint area can become stiff as the swelling impinges on the movement of the joint.
INVESTIGATIONS
Ultrasound: thickened, blurred tendon, and possible hypoechoic foci within tendon.
MRI: tendon injury.
Lymphangitis
SIGNS / SYMPTOMS
Erythema, warmth, and tenderness along the course of a lymphatic vessel from source of infection (e.g., cellulitis) to regional lymph nodes. Lymph nodes usually palpable.
INVESTIGATIONS
Doppler ultrasonography: compressible veins, absence of superficial vein thrombus.
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