Black Spots on Feet: Causes, Tinea Nigra & Melanoma

Common Causes

• Tinea nigra: Fungal infection causing dark brown/black spots on soles; common in tropics, spread via contaminated soil/water.
• Melanoma: Skin cancer appearing as irregular, jagged, or large (>6 mm) black spots. Urgent evaluation needed.
• Actinic keratosis: Precancerous scaly/crusty growths from sun exposure.
• Seborrheic keratosis: Benign dark spots from skin cell overgrowth; common in older adults.
• Hematoma: Bruise from bleeding under skin; resolves in weeks.
• Plantar warts: Viral growths on soles from contaminated surfaces.
• Foreign bodies: Dirt, splinters, glass shards.

When to See a Doctor

Any new or changing black spot that is irregular, has jagged borders, exceeds 6 mm, or is accompanied by pain, itching, or swelling should be evaluated promptly for possible melanoma.