Sometimes hand or foot injuries result in bleeding under the nail, a condition called subungual hematoma.
These bleeds can result in darkened discoloration, such as black spots, and pressure and pain.
This article will explore what’s happening under the nail in a subungual hematoma, how it’s commonly treated, and when to seek medical care.
Subungual Hematoma Explained
Subungual means “beneath a fingernail or toenail” and hematoma means “collection of blood.”
With subungual hematoma, injury to the nail results in bleeding in the nail bed, which is the soft tissue under the hard part of the nail that’s known as the nail plate.
Subungual hematoma can also affect the nail matrix, a layer of cells under the cuticle and at the base of the nail from which the nail grows.
Rapidly dividing cells of the nail matrix fill with keratin and thus become a hardened nail.
If there is bleeding under the nail but there’s no damage to the nail plate or nail fold, which attaches the nail to the skin of the finger, it’s known as a simple subungual hematoma.
If left untreated, a simple subungual hematoma typically grows out along with the lengthening nail plate and resolves on its own.
Until the nail grows out, however, you can expect weeks to months of blue-black discoloration. Interestingly, fingernails grow faster than toenails, so it takes longer for your toenails to grow out.
Sometimes, however, bleeding under the nail can result in your nail falling off (onycholysis).
In addition to discoloration, blood under the nail can lead to pressure and pain, which can be relieved by a podiatrist, a practitioner who specializes in feet (sometimes called a “foot doctor”), or another healthcare provider, such as a primary care doctor.
Other times there can be more extensive damage to the nail plate, nail fold, or finger or toe itself. Delayed treatment can result in permanent nail changes or infection.
Diagnosis
Based on the history and physical exam, most cases of subungual hematoma can be diagnosed and treated by your healthcare provider.
Also see your healthcare provider if you have other symptoms like swelling or inability to move the finger or toe. You might have a fracture. If it is continuing to bleed, you may have a laceration which requires sutures.
When a broken toe or finger is suspected, an X-ray is needed to get an image of the bone.
Rarely, what appears to be a subungual hematoma can be something else such as:
Nail bed nevus, a mole or birthmark that grows slowly or not at all Splinter hemorrhage, which is a thin red or brown-red line that looks like a splinter under the nail and can occur with heart infection (endocarditis) or psoriasis, a skin disease Longitudinal melanonychia, or black or brown nail streaks running lengthwise along the nail bed Melanoma, a form of skin cancer
All these listed conditions are painless, and, unlike subungual hematomas, they typically don’t change or change slowly.
Treatment
It takes about 48 hours for blood at the level of the nail bed to clot. If you wait longer than 48 hours to see a healthcare provider, drainage may not be possible.
In addition to being painful, nail discoloration can also be unsightly, which is another reason to seek medical help for this condition.
Nail trephination uses hot metal wire, electrocautery device, or spinning, large-bore needle to pierce the nail plate for drainage.
Fortunately, the nail plate lacks nerves, so this process doesn’t hurt.
The hole created by piercing should be large enough to let the blood drain, which takes about a day or two. During this time, the hole through which the blood oozes should be covered with sterile gauze. By performing this procedure, this can help prevent a situation in which the nail needs to be removed or in which the nail falls off by itself. Soaking your finger for 15 minutes a day in a warm solution with Epsom salts will help drain fluid and alleviate pain.
After the draining, an oral antibiotic, a medication taken by mouth to fight bacteria, shouldn’t be needed. Over-the-counter pain relievers like ibuprofen can help if you have pain.
Make sure to follow all the instructions from your healthcare provider, including methods of pain relief and caring for the finger or toe. You may be given instructions for soaking the affected area and applying clean dressings.
Your healthcare provider may also recommend elevating the affected toe or finger, using a cool compress, and applying an antibiotic ointment to the area with each dressing change.
If the hematoma covers more than half the nail or the nail injury is deep, your healthcare provider may choose to remove the nail completely.
Before removing the nail, your healthcare provider will numb the area, which is called a digital block, so that it doesn’t hurt to have it taken off.
Finally, keep in mind that it can take several months for a nail to grow back.
Summary
Subungual hematoma, or bleeding under the nail, can cause discoloration, pressure, and pain.
If you see your healthcare provider within 48 hours, it can be drained to relieve pressure.
If you have other symptoms suggesting a fracture, you experience pain, or the discoloration appears without a known cause, always see your healthcare provider.
