Cellulitis and Blood Clots: What to Know

Cellulitis is a skin and soft-tissue infection that commonly causes surface redness, warmth, tenderness, and swelling. A deep vein blood clot is a different problem involving a vein, often with swelling, aching, tightness, or warmth in one limb. The two can look similar, and one symptom does not identify the cause. A clinician considers skin findings, the limb pattern, risk factors, and circulation; an ultrasound or other testing may be needed when a clot is a concern.

Seek same-day assessment for new one-sided limb swelling, pain, warmth, or redness, particularly after prolonged immobility, surgery, a previous clot, pregnancy, or hormone treatment. Do not vigorously massage the limb or start compression garments without advice. Note when symptoms began, whether the skin is spreading or tender, and any chest symptoms. Bring a list of medicines, including blood thinners, because it affects clinical decisions.

Call emergency services for sudden breathlessness, chest pain, coughing blood, faintness, or a racing heartbeat; these can indicate that a clot has travelled to the lungs. For possible cellulitis, emergency help is also needed for confusion, severe weakness, shaking chills, rapidly spreading redness, or severe pain. Do not drive yourself if you feel faint or short of breath.

Ask whether the findings fit cellulitis, a clot, or another cause; whether imaging is needed; and which activity, pain relief, or skin care is safe. Ask how to recognise deterioration and whether any medicine interactions matter.