Why Do My Toenails Turn Black After Hiking?

By Giulia Maruzza|2025-12-22T12:48:41+00:00December 22nd, 2025|

Black toenail treatment Melbourne Podiatrist

Black toenails after hiking are extremely common, especially during multi-day treks, steep descents, and long-distance bushwalks. They can look alarming, but most cases are linked to simple mechanical overload rather than serious pathology.

What Causes Black Toenails After Hiking?

The most common reason for black toenails after hiking is a subungual hematoma – a collection of blood under the toenail caused by repeated microtrauma. Every step you take, especially downhill, pushes the toes forward into the toe box.

Long hikes also cause foot swelling, which reduces space inside the shoe. A boot that fits perfectly at the start of the day may become overly snug after 10–15 km. This traps the toes in a tight space, increasing downward and forward pressure with every step.

Downhill walking amplifies these forces dramatically. Your bodyweight shifts forward, causing increased pressure to the nail. Even well-fitted boots can become restrictive during steep descents, making black toenails a common outcome among hikers, trail runners, and backpackers.

What Other Conditions Can Look Like a Black Toenail?

While trauma is the most common cause, several conditions can mimic the appearance of a black toenail. Your Melbourne Podiatrist will always consider these differentials to ensure nothing serious is missed.

Possible differentials include:

Toenail fungus — causes yellow-brown thickening that may appear dark under certain angles.
Psoriasis — produces brownish discoloration, ridging, or pits in the nail.
Onycholysis — nail lifting from chronic pressure may cast a dark shadow beneath the nail.
Subungual melanoma (rare but serious) — often appears as a persistent dark streak that does not move as the nail grows.

How Melbourne Podiatrists Diagnose a Black Toenail

A thorough clinical assessment helps determine whether the discoloration is due to hiking trauma or another health condition.

Assessment may include:

Full medical and activity history, including recent hikes or changes in footwear.
Visual and physical Inspection of the nail to identify the type of discolouration and differential diagnoses.
Gait analysis to assess whether biomechanics (toe shape, pronation patterns, or pressure distribution) increase stress on the nails.
Footwear and sock review to identify mismatch issues.

Treatment: What Can Be Done for a Black Toenail?

If the toenail is painful, your Melbourne Podiatrist may perform a quick, sterile procedure to relieve pressure by draining the hematoma. This offers instant pain relief and helps prevent nail deformity as it grows out.

If the nail is loose or partially detached, trimming or removing the affected portion may prevent secondary infection.
Beyond immediate care, long-term preventative treatment strategies focus on stopping the trauma from happening again.

Custom Orthotics & Forefoot Load Redistribution

If your gait places excessive pressure on the tips of the toes or the nails, custom orthotics can be used to redistribute forefoot loads. By improving alignment and cushioning specific pressure points, orthotics can greatly reduce repetitive trauma under the nail. A gait analysis will identify what may be causing toenail changes through assessing the way your foot functions.

If you’ve noticed darkened/discoloured nails, are dealing with repeated nail discolouration, pain, or a cycle of nails loosening or falling off, it is worth getting things checked properly. Likewise, if you want to make sure, you’re taking the right preventative steps before your next hike, our Melbourne Podiatrists are here to help. Book an assessment and let us support you in keeping your nails healthy and pain-free.