What should you know about dark ridge on nail?

A vertical brown or black band can reflect pigment made in the nail, a small injury, medication-related change, or natural variation. A ridge that is also thick, crumbly, yellow, or lifting may occur with Nail Fungus. Pitting, tenderness, or separation can point toward Nail Psoriasis. A single dark band needs closer attention than matching changes across several nails because the pattern and its evolution help a clinician decide whether testing or further examination is needed.

Take a clear photograph in good light and record which nail is affected. Note when you first saw the band, whether it is widening, and whether the colour reaches the cuticle or surrounding skin. Keep the nail trimmed and avoid picking, aggressive buffing, or starting leftover antifungal medicine. A clinician may inspect the nail, ask about trauma and medicines, and test clippings before discussing treatment such as Oral Antifungal Treatment.

Arrange a dermatology appointment promptly for a new or widening band, irregular colour, bleeding, pain, nail destruction, or pigment spreading onto the skin beside the nail. Seek urgent care for severe throbbing pain, marked swelling, pus, or a rapidly worsening injury. These signs do not identify one diagnosis by themselves, but they should not be watched indefinitely.

Ask whether the band looks like pigment, trauma, infection, or inflammation; whether a nail sample or dermoscopic examination is useful; and which changes should prompt an earlier review.