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13 Causes for a Lump on the Side of Your Foot

lump on side of foot

Our feet quite literally carry us through our day, and any changes in them, good or bad, can be life-changing. If you've ever noticed a lump on the side of your foot and had concerns, you're not alone. In this blog post, we'll explore 10 of the most common causes of lumps on the side of the foot, causes that I see as a foot doctor daily in my patients. Hopefully, this will help shed light on these bumps and give you tips on what to do next.

13 Causes For a Lump On The Side of Your Foot

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lump on side of foot

A bunion is the most common cause of a lump on the side of the foot. A bunion is found at the base of your big toe. The bump that you see on the outside of your foot is the head of the largest long bone of the foot, the 1st metatarsal, swinging out.

Sometimes the head of the 1st metatarsal can become enlarged, making this bunion bigger. Causes of bunions are many including tight shoes that squeeze your toes together, having a flat foot, autoimmune diseases like Rheumatoid Arthritis (RA), or genetic disorders like Charcot Marie Tooth disease (CMT).

2. Bunionette/Tailor's Bunion

A bunionette or Tailor's bunion is a bunion that happens at the base of your 5th toe, also known as your baby or pinky toe. The lump that you see on the side of your foot in a bunionette is caused by the head of the 5th metatarsal.

A bunionette or tailor's bunion has similar causes to a regular bunion including tight or pointy shoes being worn over years or decades, having a flat foot, or other biomechanical changes to your feet, rheumatoid arthritis, or genetic disorders.

3. Corns and Calluses

Friction and pressure on the outside of the foot can lead to calluses and corns, which may look like a lump. Increased friction or pressure to your foot can come from shoes that are too tight to that just aren't right for your foot type, or changes in your foot shape over time due to injury, disease, or even aging.

4. Bursitis

lump on side of foot
An example of a bunion with bursitis

Bursitis is inflammation of a fluid-filled sac. Often times these sacks are normally found around joints as a form of protection. It's once they become irritated or inflamed through injury, or too much pressure when a problem or bursitis happens.

For example, in the case of bunions or bunionettes, these bursae can become inflamed as the bunion/bunionette gets worse, having both conditions seen together.

5. Ganglion Cysts

lump on side of foot

Ganglion cysts are also non-cancerous, fluid-filled sacs that often form near joints or tendons. Ganglion cysts usually happen due to some sort of injury, no matter how small, and can grow in size over time.

These cysts can cause some pain due to pressure against your shoe, or from the surrounding skin swelling.

Sometimes ganglion cysts go away on their own, but in other cases, they need to be drained by a doctor, or surgically removed to prevent them from coming back and for pain relief. Ganglionic cysts are a pretty common cause of a lump on the side of the foot as well.

6. An extra bone

Some people, as they grow can end up developing an extra bone in their foot, known as an accessory bone. These bones are usually harmless, and many people don't even know they have one until they have a foot X-ray for another reason. For some people though, these accessory bones can be painful and do cause a visible lump, usually on the side of the foot.

7. Tumors

In some cases, tumors may develop on the side of the foot. This lump can be either soft tissue like fat or even bone. The lumps can be caused by many factors like trauma or injury, genetic disorders, or abnormal cell growth which can be cancerous (cancer) or non-cancerous (benign). For this reason, it is so important to have any new lumps on your feet examined by a foot doctor.

8. Gout

lump on side of foot
An example of a gout attack

Gout is a type of arthritis caused by the buildup of uric acid crystals in and around the joints. The big toe is probably the most common place for gout to attack, but the side of the foot can also be affected by gout as well. This can lead to a painful lump on the side of your foot. Diet, changes in kidney function, and certain genetic disorders can increase your risk of developing gout.

9. Osteoarthritis

Osteoarthritis, commonly known as just arthritis is inflammation of a joint. Arthritis can happen due to age, that joint being previously injured, infection, having an auto-immune disease, added stress being placed on a joint due to being overweight, or biomechanical changes to your foot. Oftentimes, when a joint is affected with arthritis, extra bone is made around the joint, which can look like a lump, especially if that joint is located at the side of your foot.

10. Bone Spurs

A bone spur is like a hook or spike of bone. Bone spurs can develop for many reasons including trauma or injury. Bone spurs also are seen in osteoarthritis. For many people though, they don't know they even have a bone spur until they have a foot x-ray for another reason. Bone spurs, especially if they affect one of the many joints along the side of your foot can look like a lump to your eye.

11. Infections

Infections can lead to the development of a lump on the side of the foot. This lump can also be seen with pain, swelling, or drainage. Those with diabetes, neuropathy, or poor circulation are at increased risk for foot infections.

12. Rheumatoid Arthritis

lump on side of foot

Rheumatoid Arthritis (RA) is an autoimmune disease that attacks the joints. In addition to RA causing bunions, bunionettes, and other foot deformities, RA can also be responsible for something called Rheumatoid nodules. A rheumatoid nodule is a build-up of inflammatory cells. In many cases, rheumatoid nodules are found on the side of the foot and look like a lump.

13. Wart

A wart is a soft tissue growth caused by the Human Papilloma Virus or HPV. HPV has many different strains, responsible for genital warts, and certain types of cancers. HPV is also responsible for plantar warts as well. Plantar warts can be painful, especially if they are over a part of your foot that gets a lot of pressure, like the side of your foot, and can appear like a lump as well.

Key Takeaways

Finding a lump on the side of your foot can be concerning, but understanding the possible causes can help you take action. Again, if you notice any new lumps, it's so important to make an appointment with a foot doctor for an exam.

Schedule Your Appointment At Direct Podiatry Arizona

Are you in need of a foot doctor in the Phoenix area? Hello, My name is Dr. Tarr, and I am the owner of Direct Podiatry Arizona in Tempe. To view my available appointment times, click here.

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