Lymphedema: This condition is characterized by the abnormal accumulation of protein-rich fluid in the interstitial tissue, leading to swelling. It can be primary (inherited) or secondary (acquired) due to surgery, infection, or trauma. The right-sided swelling could be due to a blockage or damage to the lymphatic vessels or nodes on that side.

Deep Vein Thrombosis (DVT): A blood clot in the deep veins of the arm or leg can cause swelling, pain, and discoloration. Although DVT is more common in the legs, it can occur in the arms and could explain the right-sided swelling if the clot is located in the veins of the right arm or leg.
Cellulitis: A bacterial infection of the skin and subcutaneous tissue can cause swelling, redness, and warmth. If the infection is localized to the right side, it could explain the unilateral swelling.
Venous Insufficiency: Weak or damaged veins can lead to poor blood flow and fluid accumulation, causing swelling in the affected limb.

Superior Vena Cava Syndrome: Obstruction of the superior vena cava can cause swelling, discoloration, and shortness of breath. Although rare, this condition can be life-threatening and requires prompt diagnosis and treatment.
Compartment Syndrome: Increased pressure within a muscle compartment can cause swelling, pain, and numbness. If left untreated, compartment syndrome can lead to permanent damage and requires emergency medical attention.
Malignancy: Certain types of cancer, such as lymphoma or metastatic disease, can cause swelling due to lymphatic obstruction or tumor growth.

Klippel-Trenaunay Syndrome: A rare congenital condition characterized by abnormal blood and lymphatic vessel development, leading to swelling, varicose veins, and skin discoloration.
Parkes Weber Syndrome: A rare condition that affects the blood vessels and causes swelling, pain, and discoloration in the affected limb.
Lipedema: A rare condition characterized by the abnormal accumulation of fat in the subcutaneous tissue, leading to swelling and pain in the affected limb.