Nail Hematoma

What Causes Blood Under the Nail?

Subungual hematoma: a collection of blood trapped beneath the nail plate, usually following crush injury or repeated pressure.

Dropping something on the toe is the obvious cause. More often in diabetes, the cause is repetitive, meaning a tight shoe pressing the nail during long walks. Because sensation is reduced, patients typically discover the dark patch rather than remember the injury.

Why Does It Need Attention in Diabetes?

Three reasons. First, the injury that caused it may have damaged deeper tissue. Second, blood under the nail can become infected in a poorly supplied foot. Third, and most importantly, a dark patch under a nail is not always blood.

Melanoma can appear under a nail, and it is missed far too often because everyone assumes bruising. The distinguishing feature is simple: blood grows out with the nail over weeks, while a pigmented lesion stays where it is or spreads.

How Is It Treated?

• Small, painless collections are monitored as they grow out
• Large or painful collections are drained to relieve pressure
• The nail is checked for underlying bed injury or fracture
• Footwear is reviewed, since repeated pressure means it will recur
• Any patch not growing out is referred for specialist opinion

What Should You Watch For at Home?

Mark the position mentally and check monthly. The patch should move toward the tip as the nail grows. Additionally, come in promptly if the toe becomes painful, red, swollen or starts discharging, since those suggest infection under the nail.

What Does Treatment Cost?

Assessment is charged at standard consultation rates, and simple drainage is a minor in clinic procedure. Any imaging or specialist referral is explained and quoted separately when required.