Chronic Venous Insufficiency: This condition is characterized by the inability of veins to return blood from the legs back to the heart due to valve issues, leading to increased pressure in the veins. Petechial markings (small, pinpoint spots due to minor hemorrhages) and bilateral edema (swelling) are common symptoms, especially in the lower extremities.

Deep Vein Thrombosis (DVT): Although DVT typically presents with more pronounced unilateral symptoms, bilateral DVT or conditions leading to increased venous pressure could result in petechiae and edema. The symmetry of the symptoms might suggest other causes, but DVT should be considered, especially if there are risk factors such as recent immobility, cancer, or genetic predispositions.
Heart Failure: Congestive heart failure can lead to fluid buildup in the body, causing edema, particularly in the legs. Petechiae might not be as directly related but could occur due to decreased perfusion and increased venous pressure.
Nephrotic Syndrome: This condition involves significant loss of protein in the urine, leading to low albumin levels in the blood, which can cause edema. Petechiae could be seen in the context of associated hypoalbuminemia and possible renal failure affecting platelet function or leading to a hypercoagulable state.

Disseminated Intravascular Coagulation (DIC): A serious disorder in which the proteins responsible for blood clotting become overactive, leading to the formation of small blood clots in various blood vessels throughout the body. Petechiae are a hallmark, and while edema might not be the primary symptom, it can occur due to the consumption of clotting factors and subsequent organ dysfunction.
Sepsis: In the context of sepsis, especially if caused by certain bacteria like Neisseria meningitidis (meningococcemia), petechiae or purpura can be seen. Edema might not be the primary presentation but can occur due to capillary leak syndrome associated with severe sepsis.

Kawasaki Disease: An acute febrile illness of childhood characterized by vasculitis, which can lead to edema and possibly petechial rash, though the latter is less common.
Ehlers-Danlos Syndrome: A group of disorders that affect connective tissues supporting the skin, bones, blood vessels, and many other organs and tissues. Some types can lead to easy bruising and poor wound healing, which might present with petechiae, and edema could be seen in certain subtypes due to vascular fragility.
Scurvy: Caused by vitamin C deficiency, scurvy can lead to perifollicular petechiae and edema, among other symptoms, due to the role of vitamin C in collagen synthesis and vascular integrity.