Black Toenails From Hiking: Care and Prevention

During descents, toes can slide forward and strike the boot repeatedly. A short toe box, loose heel hold, swollen feet, long nails, and socks that bunch can increase that contact. The resulting subungual haematoma may appear purple, brown, or black and can throb when pressure builds. More than one toenail may be affected because the same footwear forces act across the forefoot. The colour can remain visible while the nail grows out, and a damaged nail may later loosen.

Take pressure off the toe, elevate the foot if swollen, and apply a wrapped cold pack for brief periods. Wash any broken skin gently and protect a loose edge with a clean, non-stick dressing. Leave the nail attached and do not puncture it yourself. Before the next hike, trim nails straight across without cutting into the corners. Check that the heel stays secure while the toe box leaves space for swollen feet, and adjust lacing before long descents. Dry, smooth socks can reduce bunching and friction.

A recently bruised nail with intense, pulsing pain should be assessed promptly; a clinician may be able to release pressure after checking the injury. Seek urgent evaluation if the toe is misshapen, numb, difficult to bear weight on, deeply cut, or still bleeding. Spreading redness, warmth, pus, fever, or increasing swelling suggest infection. If darkness appeared without a plausible hiking injury, affects only one nail in an unusual pattern, spreads onto nearby skin, or stays fixed at the base as the nail grows, arrange a dermatology assessment.

Describe the route, descents, footwear, timing of the colour change, and whether the toe was painful during or after the hike. Ask if the nail bed or bone may be injured, whether pressure release would be useful, how to dress the toe for daily activity, and when it is reasonable to return to hiking.