- Blisters: If the rubbing is intense at first, a fluid-filled blister might form, sometimes with yellowish fluid if infected.
- Fungal infections: Used shoes can harbor fungi from the previous wearer, leading to athlete’s foot or toenail fungus. However, these usually cause itching, redness, peeling, or yellowed nails rather than a distinct “bump.”
Why Used Shoes Specifically?
New shoes can cause similar issues during break-in, but used ones pose extra risks:
- They might already be shaped to someone else’s feet, causing uneven pressure.
- Poor hygiene in second-hand shoes can transfer sweat, bacteria, or fungi, worsening irritation or leading to infection.
(Images above show typical examples of yellow corns and calluses on toes caused by shoe friction.)
How to Treat It
Most yellow bumps resolve with simple home care: