Quick answer: Foot and ankle swelling is fluid building up in the tissues, which MedlinePlus calls edema. With diabetes it can come from long hours on your feet, salty food or a medicine, or from a kidney, heart, vein or foot problem. If you have diabetes, MedlinePlus and the NHS both say to get new foot swelling checked promptly.
This guide covers swelling in the feet and legs. For diabetic macular edema, swelling at the back of the eye, see NIDDK's guide to diabetic eye disease.
Why do feet swell when you have diabetes?
Gravity pulls fluid down, so swelling shows most in the feet and ankles (MedlinePlus). One foot or both is the first clue:
| Possible cause | Usually affects | What you might notice |
|---|---|---|
| Standing or sitting for hours, long trips, hot days, salty food | Both feet | Worse by evening; legs are least swollen early in the morning (MedlinePlus) |
| Weak leg veins (venous insufficiency) | One or both legs | Heavy, achy legs that feel better raised; itchy or thickened skin (MedlinePlus) |
| A medicine | Both feet | Starts after a new medicine or a higher dose |
| Kidney disease | Both feet | Feet, ankles or legs, sometimes the hands or face; often no early symptoms (NIDDK) |
| Heart failure | Both feet | Swelling with shortness of breath, tiredness or weight gain (NHLBI) |
| A blood clot, cellulitis, a hidden injury or Charcot foot | One foot or leg | Often red, warm or sore (see below) |
| Pregnancy, liver or thyroid problems, extra weight, older age | Usually both | Varies (MedlinePlus, NHS) |
Diabetes raises the odds of several of these. NIDDK says it is the leading cause of kidney disease, which about 1 in 3 adults with diabetes has, and that kidneys that can't remove extra fluid and salt can cause swelling called edema. Adults with diabetes are nearly twice as likely to have heart disease or stroke (NIDDK), and diabetes raises heart failure risk (NHLBI). And nerve damage, which up to half of people with diabetes have (NIDDK), can let an injury swell unnoticed.
Can diabetes medicines make your feet swell?
Some can, as can some blood pressure and nerve medicines. MedlinePlus drug pages say:
| Medicine (brand) | Used for | What MedlinePlus says |
|---|---|---|
| Pioglitazone (Actos, also in Actoplus Met, Duetact, Oseni) or rosiglitazone (Avandia) | Type 2 diabetes | May cause or worsen heart failure. Tell your doctor right away about swollen feet or legs, fast weight gain or shortness of breath, especially after a new or higher dose. |
| Insulin, such as insulin glargine (Lantus) or human insulin (Humulin, Novolin) | Type 1 and type 2 diabetes | Swelling of the feet or ankles, or sudden weight gain, is a serious side effect. Call your doctor right away. |
| Amlodipine (Norvasc) | High blood pressure, angina | Swelling of the feet, ankles or lower legs is a listed side effect. Tell your doctor if it is severe or lasts. |
| Pregabalin (Lyrica) or gabapentin (Neurontin) | Diabetic neuropathy, shingles, seizures | Swelling of the hands, feet, ankles or legs is a listed side effect. With pregabalin, call your doctor right away. With gabapentin, tell your doctor if it is severe or lasts. |
The combination matters. In earlier studies summarized in a 2017 trial report, about 15 in 100 people taking pioglitazone with insulin had swelling, versus 7 in 100 on insulin alone. MedlinePlus also lists steroids, estrogen, testosterone, some antidepressants and NSAIDs; its ibuprofen page says to stop it and call your doctor if your feet swell. Whatever the medicine, never stop a prescription without talking to your provider first (MedlinePlus).
Is swelling in only one foot a warning sign?
Yes. Swelling from gravity, medicines, the kidneys or the heart usually affects both feet. For new or worse swelling in one leg, MedlinePlus says to call your provider right away, and the NHS advises an urgent appointment if the cause is unclear. Rule out:
- A blood clot (DVT). The NHS lists throbbing calf or thigh pain, swelling in that leg, and red, blue or darkened skin. Chest pain or breathlessness means call 911, because a clot can travel to the lungs.
- Cellulitis. This skin infection causes red, warm, tender skin that spreads, sometimes with fever, says MedlinePlus, which lists skin sores from diabetes and cracked or peeling skin between the toes as risk factors.
- Charcot foot or a hidden injury. NIDDK says Charcot foot, a rare problem caused by nerve damage, may start with redness, warmth and swelling before bones shift or break. An unfelt sprain can swell too. NHS inform says to contact your doctor or podiatrist urgently about a hot, red, swollen foot, so don't wait for it to hurt.
Redness can be harder to see on brown or black skin, the NHS notes, so also compare warmth, size and how each shoe fits.
When are swollen feet an emergency?
Use this as a guide, not a diagnosis.
| If you notice | Do this | Why |
|---|---|---|
| Swelling with shortness of breath, chest pain or tightness, coughing up blood, or feeling faint | Call 911 | Can be a blood clot in the lungs (NHS, MedlinePlus) |
| New swelling in one leg, with pain, warmth or redness | Call your doctor right away | Possible DVT (NHS, MedlinePlus) |
| A hot, red, swollen foot, a change in foot shape, or swelling with fever or chills | Call your doctor or podiatrist today | Possible infection or Charcot foot (NIDDK, NHS inform, CDC) |
| A cut, crack or sore on a swollen foot, or a sore that turns black or smells bad | Call your doctor right away | Report sores and cracks right away (MedlinePlus); NIDDK says the same for an infection that turns black and smelly |
| Pregnant or just gave birth, with sudden swelling of the face, hands or feet, a bad headache or vision changes | Call your midwife, OB or doctor now | Possible pre-eclampsia, which the NHS says needs checking immediately |
| Fast weight gain, needing extra pillows to breathe, or worse swelling with heart, kidney or liver disease | Call your doctor right away | Signs of fluid buildup MedlinePlus says to report right away |
| Mild swelling in both feet that goes down overnight | Call your doctor's office and ask for a prompt visit | For anyone with diabetes, the NHS advises an urgent GP appointment for swollen feet, ankles or legs |
What helps mild foot and ankle swelling at home?
Once your doctor rules out a serious cause, try these steps:
- Raise your legs on pillows above your heart when lying down (MedlinePlus), or on a chair when sitting (NHS). If that makes you short of breath, stop and see your provider (MedlinePlus).
- Keep your legs moving. Leg exercise helps pump fluid back toward your heart (MedlinePlus), so wiggle your toes and move your ankles through the day (NIDDK) and walk around often on long trips.
- Go easy on salt, a common cause of swollen ankles (NHS), and lose weight if you need to (MedlinePlus).
- Loosen anything tight, from clothes to socks and shoes (NHS). NIDDK adds: no rubber bands to hold up socks.
- Wash, dry and moisturize your feet to help avoid infections, the NHS says, but keep lotion out from between your toes (NIDDK).
- Skip foot soaks. Some websites suggest Epsom salt soaks, but NIDDK tells people with diabetes not to soak their feet, because it dries the skin.
- Leave stockings and water pills to your doctor. MedlinePlus mentions support stockings and prescription water pills (diuretics), but with diabetes, ask before you try either.
Do diabetic socks help with swollen feet?
They won't make swelling go down. What a diabetic sock can do is avoid adding a tight band to a puffy ankle: the ADA says socks made for people with diabetes have an elastic area in and around the ankle so they are not too constricting.
A 2017 double blind trial tested this. In it, 80 adults with diabetes and leg swelling wore knee-high diabetic socks for 4 weeks. Only the group in mild compression socks (18 to 25 mmHg) had a statistically clear drop in ankle and calf size, of under 1 cm on average, and everyone had leg artery checks before joining, so ask your doctor before trying compression. The non-compression group's changes were smaller and not statistically clear. By week 4, most people in both groups rated their socks very comfortable.
The ADA suggests asking your provider about compression if you have weak leg veins, leg or foot swelling, a past leg clot, or long hours on your feet. "Edema socks" can mean either kind, so ask your doctor which you need, and see diabetic socks vs compression socks.
A word on our own socks: Mi Socks are non-binding crew and knee-high comfort socks with a loose top, smooth flat toe seam, terry-cushioned sole and breathable cotton-rich blend. They are not compression socks and won't bring swelling down. A knee high does put the top band higher, away from puffy ankles. Browse our socks for swollen feet, the Mi Socks Knee High 6-pack ($6.17 a pair) or the Crew 6-pack at $6 a pair. Both ship free in the US, like any order of $19 or more. For fit and sizing, see the best socks for swollen feet and ankles.
How should you check swollen feet every day?
NIDDK suggests checking your feet each evening, including between the toes, with a mirror or helper if needed, for swelling, warm spots, cuts, sores and blisters. With swelling, also:
- Compare both feet for size, color and shape. The CDC says a change in foot shape means see your doctor right away.
- Feel for warmth with the back of your hand; MedlinePlus says to report redness, extra warmth or swelling anywhere on a foot. A colder foot matters too (see cold feet and diabetes).
- Do the press test. Press a finger on the swollen spot for about 5 seconds. A dent that slowly fills back in is what MedlinePlus calls pitting edema; tell your doctor how deep it was and how long the dent lasted.
- Notice your socks and shoes. Shoes that suddenly feel tight can mean more fluid (MedlinePlus), and so can deeper sock marks. With heart failure, weigh yourself each morning and call if you gain more than 2 to 3 pounds in a day or 5 in a week (MedlinePlus).
- Write it down: which foot, how far up the leg, whether it is gone by morning, and any new medicine. Your provider will ask (MedlinePlus).
More in our diabetic foot care checklist.
Frequently asked questions
Can swollen feet be a sign of diabetes?
Not usually. The CDC's symptom list includes numb or tingling feet and sores that are slow to get better, but not swelling. Never been tested? Ask your doctor.
Can high blood sugar make your feet swell?
Indirectly, over time, through the kidney, heart and nerve problems above. NIDDK says high blood glucose can damage the blood vessels in your kidneys, and that reaching your glucose and blood pressure goals is the best way to slow diabetic kidney disease.
Why do my feet swell more at the end of the day?
Gravity makes swelling most noticeable low in the body, and legs are least swollen early in the morning (MedlinePlus). With diabetes, still get swollen feet checked (NHS), and call right away about new swelling in one leg (MedlinePlus).
Will diabetic foot swelling go away?
It depends on the cause. The NHS says everyday swelling often goes away on its own, and that if it doesn't, your doctor can help find the right care. If you think a medicine is to blame, don't stop it on your own; ask your doctor first (MedlinePlus).
Should I take a water pill for swollen feet?
Only if your doctor prescribes one. MedlinePlus lists water pills (diuretics) and cutting back on salt among the options a provider may use once they have looked for the cause. Never take someone else's.
Sources
- MedlinePlus. Foot, leg, and ankle swelling; Swelling; Diabetes: taking care of your feet; Deep vein thrombosis; Cellulitis; Venous insufficiency; Compression stockings; Heart failure: home monitoring.
- MedlinePlus drug pages: Pioglitazone, Rosiglitazone, Insulin Glargine, Human Insulin, Amlodipine, Ibuprofen, Pregabalin, Gabapentin.
- NIDDK. Diabetes & Foot Problems; Peripheral Neuropathy; Diabetic Kidney Disease; Chronic Kidney Disease; Diabetes, Heart Disease, & Stroke; Diabetic Eye Disease.
- NHS. Swollen ankles, feet and legs (oedema); DVT; Pre-eclampsia. NHS inform. Diabetic foot issues.
- NHLBI. Heart failure symptoms; causes and risk factors.
- American Diabetes Association. 8 Tips to Protect Your Feet with Diabetes.
- CDC. Your Feet and Diabetes; Diabetes Symptoms.
- Wu SC, Crews RT, Skratsky M, et al. Double blind trial of mild-compression vs non-compression diabetic socks in adults with diabetes and leg swelling. Diabetes Res Clin Pract. 2017;127:35-43.
About this guide
Written by the Mi Socks team, last reviewed October 13, 2026. We sell non-binding socks, so weigh what we say about our own pair accordingly. No doctor, nurse or podiatrist has reviewed this guide (see how we write). It is general information, not medical advice. Mi Socks are non-compression comfort socks for everyday wear. They are not a medical device and are not intended to diagnose, treat, cure, or prevent any disease. If you have diabetes, neuropathy, poor circulation, or a foot wound, check your feet every day and follow your doctor's or podiatrist's advice. See our medical information page.