One Swollen Ankle: Cause & What to Do?

Case 1: One Swollen and Painful Ankle

When only one ankle is swollen, it’s more likely to also be painful.

These pains can occur at rest, without doing anything. Or only when walking or running. Or when touching or pressing on the ankle.

Here are the most common causes of a swollen ankle with pain:

• Ankle sprain: Stretching or tearing of the ankle ligaments due to a twist of the foot.
• Ankle fracture: Crack or break in the bones of one or both of the ankle’s malleoli.
• Tendinitis: Inflammation of a tendon in the ankle.
• Arthritis: Inflammation of the ankle joint.
• Gout: Accumulation of uric acid crystals in the ankle joint.
• Bursitis: Inflammation of the synovial bursa in the ankle, a component within the joint.
• Infection: Often following a trauma or surgery, especially if there has been a wound.

💡 See also: How to know if you have an ankle sprain or fracture?

Case 2: One Swollen Ankle Without Pain

Is your ankle swollen but you have no pain at all?

No pain at rest, when walking, or when moving your foot?

Here are the most likely causes of this swelling:

• Water retention (edema): Simply having a swollen ankle due to fluid accumulation, without any specific cause! It’s more common to have both ankles affected, but not necessarily.
• Venous insufficiency: A blood circulation problem in the ankle.
• Lymphedema: Swelling of the ankle due to a malfunction of the lymphatic system.
• Allergic reaction.
• Medications: Side effects of certain medications causing ankle swelling, such as antihypertensives or anti-inflammatories.
• Varicose veins: Dilated and swollen veins in the ankle.
• Deep vein thrombosis (DVT): Formation of blood clots in the deep veins of the ankle, often following surgery or prolonged bed rest.

Pain is only one of many indicators that help determine the cause of swelling. It can provide clues, but it is not sufficient on its own!

Has your ankle been swollen for a long time or a short time?

In a publication aimed at healthcare professionals, the authors recommend considering when the swelling appeared:

• Is the onset recent? Less than 3 days, or 3 months?
• Is the onset long-standing? More than 3 months?

Here are the most common causes of swelling on one side of the ankle, depending on whether the swelling has been present for a long time or not:

When Should You See a Doctor for a Swollen Ankle on One Side?

Very often, while browsing the internet or reading magazines, you will come across articles that say something like, “If in doubt or concerned, it’s crucial to consult your doctor.”

My goal here is not to repeat this widely read formula, although I understand why many health and medical writers use it. Instead, I aim to be as precise as possible in advising you on when to consult a doctor or not.

In the vast majority of cases, swelling in the ankle without any other symptoms does not require immediate consultation.

You can simply mention it to your primary care physician during your next scheduled visit for another reason, if it still worries you at that time.

Other symptoms associated with ankle swelling may, on the contrary, prompt you to consult without urgency.

These symptoms include:

• If you have great difficulty walking while bearing weight on the ankle, or if it feels unstable or extremely painful when walking;
• If you have a fever not explained by an ongoing illness like the flu or a bad cold;
• If your skin has rapidly changed color, becoming purplish or very red;
• If you have lost a lot of weight recently or feel generally unwell.

How Can You Be Sure It’s Not Something Serious?

Even though it’s often impressive and worrying, swelling in one ankle is, in the vast majority of cases, something benign.

Benign doesn’t mean not annoying. But it means that it is not a sign of a more serious underlying disease in the vast majority of cases.

Try to Rationalize the Situation

Cognitive biases often lead us to immediately think of serious conditions like cancer when we encounter less severe symptoms, such as simple swelling.

Given that serious diseases like cancer are often more publicized and discussed, they are more mentally accessible, which can make us consider them more likely.

Additionally, once we have an idea in our mind, we tend to seek information that confirms it rather than information that contradicts it. If we are worried about a serious condition, we might ignore evidence suggesting otherwise.

Seek Opinions from Others

If these explanations are not enough to reassure you, you can seek the opinion of someone in your circle. Explain your thoughts to them and why you think it might be something serious.

Confronting your thoughts with someone else’s can help you gain perspective.

And based on that, you can decide whether or not to seek medical advice.

Can the Swelling Go Away on Its Own?

Yes, absolutely. As a physical therapist, I have numerous examples of conditions where ankle swelling resolves on its own over time without specific treatment.

For example, after a ligament rupture in the ankle (grade 2 or 3 sprain) or in cases of water retention, which is often more significant in the summer.

So keep hope: if you have ankle swelling, it can go away on its own with time.

Now, are there things you can do to speed up the disappearance of the ankle swelling, regardless of the cause?

What to Do When You Have One Swollen Ankle

Depending on the cause of your ankle swelling, there may be specific treatments.

For example, in the case of rheumatoid arthritis, a rheumatic disease causing joint inflammation (arthritis).

But in the vast majority of cases, medical, non-medical, or surgical treatments for ankle swelling are the same.

I have already dedicated a complete article to this topic, which I invite you to read: how to reduce swelling in a swollen ankle?