A nail biopsy is a minor surgical procedure involving the removal of a small tissue sample from the nail unit to diagnose the cause of persistent or unusual nail changes. The nail unit includes the nail plate, nail bed, surrounding nail folds, and the matrix where the nail grows. This procedure is performed when visual inspection or non-invasive tests, like fungal scrapings, have not provided a clear diagnosis for issues such as chronic discoloration, abnormal thickness, or unexplained nail separation. The biopsy provides the necessary tissue for a pathologist to microscopically examine the cellular structure and identify the underlying condition.
Preparing for the Biopsy
Before the procedure, discuss all current medications with your healthcare provider. This is especially important regarding blood-thinning agents, such as aspirin, ibuprofen, and prescription anticoagulants like warfarin or clopidogrel. Because these medications increase the risk of bleeding, they may need to be temporarily stopped for three to seven days prior to the biopsy, but only under your prescribing doctor’s guidance.
You must ensure the nail area is completely clean and free of cosmetic enhancements. All nail polish, gels, or artificial nails must be removed from the affected finger or toe before arriving. If the biopsy is on a toenail, plan to wear loose-fitting or open-toed shoes afterward to accommodate the surgical dressing. Arranging for a driver is also advisable, particularly if you are prone to anxiety or if the procedure site is a foot.
What Happens During the Biopsy
The procedure begins with the administration of a local anesthetic, typically a digital block, which numbs the entire finger or toe. This involves several injections near the base of the digit, causing a brief sting or pressure before the area becomes numb. Once the anesthetic takes full effect (which may take up to 15 minutes), the surgical area is cleaned with an antiseptic solution.
The doctor selects the appropriate technique based on the location and nature of the condition. A punch biopsy uses a small circular tool to remove a cylindrical sample from the nail bed or matrix, often without removing the overlying nail plate. For lesions running the length of the nail, a longitudinal wedge excision may be performed, removing a narrow strip of tissue through the entire nail unit.
In some cases, the nail plate over the biopsy site may need to be partially or completely lifted to access the tissue underneath. During tissue removal, you should only feel pressure or tugging, not pain, since the area is anesthetized. Once the tissue sample is secured and placed in a preservative, the small wound is closed, often with fine sutures, and a protective dressing is applied.
Caring for the Site After Surgery
After the procedure, the digit will have a protective dressing in place to help minimize bleeding and protect the wound. Keep this initial dressing clean and dry for the first 24 hours. Elevating the hand or foot above the level of the heart for the first day helps reduce swelling and throbbing pain.
You may experience minor pain as the local anesthetic wears off, which is usually managed with over-the-counter pain relievers, such as acetaminophen. After the initial 24-hour period, change the dressing daily. Cleanse the wound gently with soap and water and apply a thin layer of sterile petroleum jelly or an antibiotic ointment. This process prevents the formation of a hard scab, which can delay healing.
Avoid strenuous activities and prolonged water exposure, like swimming or soaking in a bath, for about one to two weeks to allow proper healing. If sutures were placed, they are typically removed by the doctor during a follow-up appointment ten to fourteen days after the biopsy. Contact your doctor immediately if you notice signs of infection, such as increasing pain, spreading redness, swelling, or pus draining from the site.
Timeline for Receiving Results
Once the tissue sample is collected, it is sent to a pathology laboratory for microscopic analysis. At the lab, the sample is chemically fixed, embedded in paraffin wax, sliced into thin sections, and then stained for examination by a pathologist. This preparation ensures that the cellular structures are clearly visible for accurate diagnosis.
The time required for analysis varies based on the lab’s workload and the complexity of the condition. Generally, you can expect results within one to three weeks following the procedure. If the pathologist needs to perform additional specialized stains or tests to confirm a diagnosis, the timeline may be slightly longer.
Your healthcare provider reviews the final pathology report, which confirms whether the abnormal nail change is due to a fungal infection, an inflammatory skin condition, or a tumor. Results are typically communicated during a scheduled follow-up appointment, often coinciding with the suture removal visit. This conversation establishes a definitive diagnosis and informs the necessary treatment plan.