What should you know about skin growth under toenail?

A bump beneath the nail can be related to repeated shoe pressure, a prior injury, a wart, fungal or bacterial infection, or a cyst near the nail bed. Dark colour after trauma may reflect trapped blood, while a new or widening pigmented area needs assessment. A lesion that grows, bleeds, becomes painful, or does not heal may require a clinician to consider conditions such as [Basal Cell Carcinoma](/conditions/basal-cell-carcinoma/); the growth itself does not establish that diagnosis. General information on [Skin Lumps](/symptoms/skin-lumps/) may help you describe it.

Do not drill into the nail, cut beneath it, or apply acid-based products. Keep the nail trimmed without digging at the edges, choose footwear with room for the toes, and keep feet clean and dry. Photograph the nail in good light so gradual changes are easier to notice. A dermatologist or podiatry clinician may examine the nail, gently sample material for infection, or recommend a biopsy when the cause is uncertain.

Arrange prompt assessment for a stripe or patch that widens, pigment that reaches the surrounding skin, bleeding, drainage, nail destruction, or a lump that persists after an injury should have settled. Seek urgent care for rapidly spreading redness, severe throbbing pain, fever, or inability to walk comfortably. People with diabetes, poor circulation, or reduced immunity should seek advice early for a painful or infected-looking toe.

Ask whether the change fits trauma, infection, or a nail-bed lesion; whether a sample or biopsy is needed; and how long observation is reasonable. Discuss footwear, wound care, nail regrowth, and signs that need rechecking. If inflammation or a raised scar is suspected, ask whether [Steroid Injection Into The Skin](/treatments/injectables/intralesional-steroid-injection/) has a role.