What should you know about unilateral pitting oedema?

Fluid has collected in the tissues, often around the foot, ankle or lower leg. Pressing gently for a short time may leave a temporary hollow. One-sided swelling can follow prolonged standing, injury, inflammation, a blocked vein or problems with drainage through the lymphatic system. The appearance alone cannot identify the cause. Redness, warmth and tenderness may accompany Cellulitis; itchy raised areas may fit Hives, while deeper swelling of the skin can occur with Angioedema. A clinician may compare both limbs, check pulses and sensation, review medicines and decide whether imaging or other tests are needed.

Measure and record when the swelling began, whether it changes during the day, and any pain, redness, breathlessness or recent travel, surgery or injury. Remove tight clothing or jewellery from the swollen area. Avoid vigorous massage or starting compression garments until a clinician has assessed sudden one-sided swelling. Resting with the limb supported may be reasonable for mild swelling after an obvious minor strain, but it should not delay review when the cause is unclear. Do not use leftover antibiotics or water tablets without medical advice.

Seek urgent medical care for sudden swelling, calf pain, warmth, marked redness, a tense limb, or swelling that is rapidly worsening. Call emergency services for breathlessness, chest pain, coughing blood, fainting or sudden confusion. Facial or tongue swelling with trouble breathing also requires emergency help. Fever with rapidly spreading red skin should be assessed urgently.

Ask what findings suggest fluid retention, infection, injury or a circulation problem, and whether you need an ultrasound or other test. Clarify which activities, elevation or compression are suitable, and which changes should send you back for urgent review.