Swelling on the inside of the ankle is common, and where it sits is a useful first clue. Puffiness tucked on the inner side of one ankle usually points to a problem in the tendons, ligaments, or joint right there. Swelling around both ankles usually means fluid is collecting from elsewhere in the body. A few patterns, like sudden swelling in one leg with chest pain or breathlessness, can’t wait.
The Most Common Local Cause Is a Worn Tendon or Sprained Ligament
The posterior tibial tendon runs down the inside of the ankle, behind the bony bump, and helps hold up the arch of the foot. When it is overloaded for a long time, it becomes chronically irritated and worn. Rarely it tears, especially in people on long-term steroid medicines.1Essentials of Physical Medicine and Rehabilitation. Posterior Tibial Tendon Dysfunction Once it can’t support the arch properly, the arch gradually sags, and this tendon problem is the most common reason adults develop a flat foot later in life.2PubMed. Posterior tibial tendon dysfunction
It most often affects middle-aged women, whose main complaint is pain on the inside of the ankle and heel.3Essentials of Physical Medicine and Rehabilitation. Posterior Tibial Tendon Dysfunction The pain and swelling along the inner foot and ankle tend to get worse with activity.4PubMed Central. Posterior Tibial Tendon Dysfunction: An Overlooked Cause of Foot Deformity As the arch collapses further, people often notice their shoes wearing unevenly.5PubMed Central. Posterior Tibial Tendon Dysfunction: An Overlooked Cause of Foot Deformity
A twist can instead sprain the deltoid ligament, a fan of tough tissue on the inner ankle that keeps that side stable.6PubMed. Medial Ankle Instability: Review of Anatomy, Evaluation, and Treatment A sprain there causes pain, tenderness, and swelling on the inside of the ankle.7Nationwide Children’s Hospital. Sports Medicine: Deltoid Ligament Sprain These sprains are less common than the familiar outer ankle sprain. If one heals poorly, it can leave the ankle feeling unstable and raise the risk of arthritis later.8PubMed. Medial Ankle Instability: Review of Anatomy, Evaluation, and Treatment
The two problems start differently. Tendon trouble usually builds over weeks or months without a single injury you can name, and the swelling sits in a line just behind and below the inner ankle bone. A sprain follows a specific twist, roll, or fall and swells within hours, with swelling and bruising that tend to spread around the ankle.
You can look for clues at home. Standing barefoot, compare how high each arch sits; a lower arch on the sore side is a hint. Try rising onto the toes of the sore foot alone, since difficulty or pain suggests a weak tendon. These are clues to bring to a doctor, not a diagnosis.
Less Common Causes Inside the Ankle
Gout is a form of arthritis caused by uric acid forming crystals in and around joints.9PubMed Central. Gout arthritis of the ankle successfully treated with arthroscopic debridement: A case report An attack brings sudden, intense pain and swelling, often in a single joint.10PubMed Central. Revisiting the pathogenesis of podagra: why does gout target the foot? The big toe is the most common target, but the ankle is affected in about half of people with gout over time.11ReumatologÃa ClÃnica (English Edition). Gouty Involvement of Foot and Ankle: Beyond Flares So a hot, very tender, swollen ankle that came on overnight without injury could be gout.
The skin over a gouty joint may look red and shiny and feel hot, and even a bedsheet touching it can hurt. Past attacks in the big toe make gout more likely.
The bony bump on the inner ankle can develop a small stress fracture from repeated load rather than one injury.12PubMed Central. Medial malleolar stress fracture resulting from repetitive stress caused by lateral ankle instability Runners, dancers, and people who suddenly increase their training are the likeliest to get one, as are those with repeated ankle sprains in their past. The typical pattern is pain that eases with rest and returns with activity. Aching and swelling over the bone deserves an X-ray. Early X-rays can look normal, so follow-up imaging may be needed.
Some inner ankle problems cause symptoms without much swelling. Tarsal tunnel syndrome is a nerve squeezed as it passes through a narrow channel on the inner ankle.13PubMed. Tarsal tunnel syndrome: a compression neuropathy involving four distinct tunnels Its main sign is numbness, tingling, or burning on the inside of the ankle and sole rather than obvious puffiness. Rarely, a fluid-filled cyst growing in the nerve itself causes it.14PubMed Central. Ultrasound facilitates the diagnosis of tarsal tunnel syndrome: intraneural ganglion cyst of the tibial nerve Some people also have an extra small bone on the inner side of the foot that can become painful, especially in teens and young adults.15PubMed Central. The accessory navicular
When Both Ankles Swell, Look Beyond the Ankle
When leg veins struggle to push blood back up, fluid pools low in the legs. Vein-related swelling usually affects both legs similarly and shows most around the ankles and lower legs.16Vascular Surgery Associates. 5 Ways to Tell Lymphedema Apart from Venous Insufficiency Standing for half or more of a work shift is linked with more vein disease, and the risk rises with age.17American Journal of Industrial Medicine. Chronic venous disorders and occupation
A typical day of vein swelling goes like this: slim ankles in the morning, puffy ones by evening, and socks that leave deep marks. Legs may feel heavy or achy after standing. Overnight, with the legs up, the swelling shrinks.
Several common medicines cause ankle swelling. Calcium channel blockers, a common class of blood pressure medicines that includes amlodipine, often cause it, and higher doses make it more likely.18PubMed Central. Etiology of Drug-Induced Edema: A Review of Dihydropyridine, Thiazolidinedione, and Other Medications Causing Edema Regular use of anti-inflammatory painkillers like ibuprofen and naproxen makes the kidneys hold onto salt and water.19PubMed Central. Etiology of Drug-Induced Edema: A Review of Dihydropyridine, Thiazolidinedione, and Other Medications Causing Edema Some diabetes medicines, such as pioglitazone, can cause swelling.20PubMed Central. Etiology of Drug-Induced Edema: A Review of Dihydropyridine, Thiazolidinedione, and Other Medications Causing Edema Steroids and hormone treatments can also contribute to fluid retention.21Judson Siegel Podiatry. Swollen Ankles and Possible Medication Causes If swelling began after starting a new medicine, ask your doctor rather than stopping it on your own.
Lymphedema, a backup of the body’s drainage fluid, tends to swell one leg more than the other and can include the foot.22Vascular Surgery Associates. 5 Ways to Tell Lymphedema Apart from Venous Insufficiency Among people seeing a family doctor for swelling in both legs, heart conditions and high blood pressure in the lungs were the most common causes.23PubMed. Etiology and diagnosis of bilateral leg edema in primary care In heart failure, leg swelling often starts at the ankles and can climb higher as fluid builds.24PubMed. Pathophysiology of lower extremity edema in acute heart failure revisited Clues that the heart is involved include breathlessness when lying flat or waking up short of breath, needing extra pillows to sleep, tiring more easily on stairs, and swelling that keeps creeping up the legs.
Mild puffiness in both ankles after a long day on your feet, a long flight, or a hot day is common and often has no disease behind it, because gravity pulls fluid down into the lowest part of the body. A very salty dinner can add to it. Swelling is worth investigating when it is new, keeps getting worse, doesn’t go down overnight, or comes with other symptoms such as breathlessness.
Check Your Own Swelling With the Press Test
Pitting edema means swollen skin keeps a dent after you press it. Press the foot or lower leg firmly for 10 seconds, then grade the dent:25umms.org. How to Tell if You Have Edema
- 0: the skin springs back right away.26umms.org. How to Tell if You Have Edema
- 1+: you can barely see a dent.27umms.org. How to Tell if You Have Edema
- 2+: a light dent that fades within 15 seconds.28umms.org. How to Tell if You Have Edema
- 3+: a deeper dent that takes up to 30 seconds to fade.29umms.org. How to Tell if You Have Edema
- 4+: a deep dent that lasts more than 30 seconds.30umms.org. How to Tell if You Have Edema
Where the swelling sits matters too. Pitting swelling running only along the line of the inner ankle tendon, with no injury and no swelling elsewhere, is a sign doctors use to spot posterior tibial tendon trouble.31PubMed. Validity of the posterior tibial edema sign in posterior tibial tendon dysfunction
A simple log helps. Note the date, time, and pitting grade for each ankle, and whether swelling is worse in the evening. Write down new medicines or long trips, and take photos to show your doctor.
When Inner Ankle Swelling Needs Urgent Care
- Sudden swelling in one leg, especially after travel or bed rest, with calf pain, warmth, or tenderness can mean a DVT (deep vein thrombosis), a clot in a deep leg vein.32Achilles Foot and Ankle Center. What Causes Ankle Swelling? 15 Reasons & Quick Relief
- Swelling with chest pain or shortness of breath can mean a clot has reached the lungs or the heart is struggling. Call emergency services.33New England Podiatry. Why Are My Ankles Swollen?
- Fever, chills, or redness that spreads quickly may signal a skin or joint infection.34Achilles Foot and Ankle Center. What Causes Ankle Swelling? 15 Reasons & Quick Relief
- Being unable to put weight on the foot, or a visibly deformed ankle after an injury, needs urgent evaluation and often an X-ray.35American Medical Association. What doctors want patients to know about ankle sprains and strains
- New numbness, tingling, or skin that turns purple or shiny and tight needs prompt attention.36Achilles Foot and Ankle Center. What Causes Ankle Swelling? 15 Reasons & Quick Relief
- During pregnancy, swelling with a severe headache, vision changes, or high blood pressure needs urgent care.37Achilles Foot and Ankle Center. What Causes Ankle Swelling? 15 Reasons & Quick Relief
- Gaining more than 2 pounds in a day or waking breathless at night can be a heart failure warning.38Achilles Foot and Ankle Center. What Causes Ankle Swelling? 15 Reasons & Quick Relief
A leg clot is easy to dismiss because it can feel like a pulled calf muscle: a dull ache, tightness, or cramp that doesn’t ease with stretching or rest. The leg may look slightly redder or feel warmer than the other, and the swelling is often only in that leg. Some clots cause few symptoms, so after a recent long trip, surgery, or bed rest, any new one-sided swelling is worth checking quickly even if it seems mild.
Other signs call for a regular appointment rather than the ER: swelling that lasts more than a week or two without a clear cause, inner ankle pain with a sagging arch, swelling that started with a new medicine, and repeated sprains or an ankle that feels unstable.
Easing the Swelling at Home
Compression stockings with about 20 mmHg of pressure can reduce leg swelling after long sitting or standing.39Annals of Vascular Diseases. Compression Therapy: Clinical and Experimental Evidence In people with diabetes, mild compression socks reduced ankle swelling without harming blood flow.40PubMed Central. Control of Lower Extremity Edema in Patients with Diabetes: Double Blind Randomized Controlled Trial Assessing the Efficacy of Mild Compression Diabetic Socks Check with a doctor first if you have poor circulation in your legs. Putting stockings on in the morning, before swelling builds, works best.
For fluid swelling, raise your legs above heart level for 20 to 30 minutes a few times a day. Lie down and prop your feet on pillows, because a footstool while sitting up barely changes how fluid drains. If elevation brings no change after several days, see a doctor rather than keep waiting. During long stretches of sitting, take short walks or do ankle pumps, and cut back on salty foods.
Injuries need support and rehab. After a sprain, braces and foot supports help in the first weeks, followed by a structured exercise program.41PubMed Central. Rehabilitation of the Ankle After Acute Sprain or Chronic Instability Arch supports can correct the inward roll of the foot in runners.42PubMed. Arch-support foot-orthoses normalize dynamic in-shoe foot pressure distribution in medial tibial stress syndrome For a sore tendon or sprain, rest from the activities that cause pain, use ice for 15 to 20 minutes after activity, and wear supportive shoes instead of flat sandals. Rebuild strength gradually with balance exercises.
How Doctors Find the Cause and Treat It
The doctor will ask when the swelling started and whether there was an injury, whether one or both ankles are swollen, and which medicines you take, including new ones. They’ll also ask about breathlessness, chest pain, or weight gain.
The exam compares both legs standing and sitting for size, skin color, and warmth, and checks your arch from behind to see whether it has dropped. The doctor presses along the inner ankle to find exactly where it is tender, which helps separate tendon, ligament, and bone problems. They also check your pulses and press on the swollen skin to see whether it pits, which helps decide whether fluid is the cause.
Ultrasound is quick and inexpensive, and works well for spotting tendon and ligament injuries.43Egyptian Journal of Radiology and Nuclear Medicine. High resolution ultrasonography and magnetic resonance imaging in the evaluation of tendino-ligamentous injuries around ankle joint It can mistake a complete ligament tear for a partial one, so MRI is often used to confirm severe injuries.44Egyptian Journal of Radiology and Nuclear Medicine. High resolution ultrasonography and magnetic resonance imaging in the evaluation of tendino-ligamentous injuries around ankle joint X-rays are used to look for fractures.45American Medical Association. What doctors want patients to know about ankle sprains and strains For body-wide causes, blood tests can check kidney function and protein levels, a vein ultrasound can look for clots or weak veins, and heart tests may be needed if both legs are swollen.
Most tendon problems are first treated with supports, braces, and exercises. If these fail, surgery can rebuild the tendon using a nearby one and often reshape the heel bone.46PubMed. Surgical reconstruction of posterior tibial tendon dysfunction: prospective comparison of flexor digitorum longus substitution combined with lateral column lengthening or medial displacement calcaneal osteotomy After surgery people usually keep weight off the foot for 2 to 6 weeks in a cast or boot.47Journal of Arthroscopic Surgery and Sports Medicine. Non-operative and operative management of posterior tibialis tendon dysfunction – A systematic review and meta-analysis These surgeries usually improve function.48Journal of Arthroscopic Surgery and Sports Medicine. Non-operative and operative management of posterior tibialis tendon dysfunction – A systematic review and meta-analysis