What Is a Nail Biopsy?

A nail biopsy involves removing a portion of the nail plate, nail bed, nail fold, or nail matrix for microscopic examination. Because nail problems can stem from infections, inflammatory diseases, trauma, or even tumors, a biopsy provides the most accurate way to determine the underlying cause.

Conditions Commonly Diagnosed

Nail biopsies are performed when nail changes are unexplained, persistent, or suspicious. They can help diagnose:

• Fungal infections (onychomycosis)

• Psoriasis and other inflammatory skin conditions affecting nails

• Lichen planus (causing ridges, thinning, or discoloration)

• Pigmented streaks or melanonychia, to rule out melanoma

• Benign or malignant tumors of the nail unit

• Trauma-related nail deformities

• Chronic nail dystrophy (rough, brittle, or thickened nails)

Types of Nail Biopsies

Depending on the suspected condition, different techniques may be used:

• Nail plate biopsy – a small piece of the nail plate is clipped or shaved; often used for fungal cultures.

• Nail bed biopsy – tissue beneath the nail is sampled, usually after partial nail removal.

• Nail fold biopsy – tissue from the skin around the nail edges is taken to evaluate periungual lesions.

• Nail matrix biopsy – tissue from the nail’s growth center is sampled, often to rule out melanoma.

• Longitudinal biopsy – samples nail matrix, bed, and fold together for complex or large lesions.

What to Expect During the Procedure

• The area is cleaned and numbed with local anesthesia.

• In some cases, the nail plate is partially or fully removed to access the biopsy site.

• A small tissue sample is taken using scissors, a punch tool, or a scalpel.

• The site may be sutured for healing, especially if the nail matrix is involved.

• Mild pain or throbbing can occur for a few days afterward, but most patients recover quickly.