Differential Diagnosis for a Painful Hard Bump on the Bottom of the Foot
- Single most likely diagnosis:
- Plantar wart: This is the most likely diagnosis given the description of a hard bump that resembles a wart or corn on the bottom of the foot, which is a common location for plantar warts. The pain associated with it, especially when pressure is applied, further supports this diagnosis.
- Other Likely diagnoses:
- Corn or callus: These are thickened areas of skin that can develop due to repeated pressure or friction, which could cause pain, especially if they become inflamed or infected.
- Plantar keratosis: A condition characterized by thickening of the skin on the bottom of the foot, often due to pressure, which can be painful.
- Ingrown toenail: Although typically associated with the toes, an ingrown toenail can cause a painful bump if it becomes infected or if the nail grows into the surrounding skin.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
- Melanoma: Although rare, a melanoma on the foot, known as acral lentiginous melanoma, can present as a new or changing growth and must be considered to avoid missing a potentially deadly diagnosis.
- Squamous cell carcinoma: This type of skin cancer can appear as a firm, growing bump and is more common in areas exposed to the sun, but can also occur on the foot.
- Infection (e.g., abscess, cellulitis): An infection in the foot can cause a painful bump and requires prompt treatment to prevent serious complications.
- Rare diagnoses:
- Plantar fibroma: A benign growth on the bottom of the foot that can cause pain, especially if it grows large enough to press on nerves or other structures.
- Glomus tumor: A rare, benign tumor that typically occurs under the nail but can also appear on the bottom of the foot, causing significant pain.
- Foreign body reaction: If something like a splinter or other foreign object becomes embedded in the foot, it can cause a painful bump as the body reacts to the foreign material.