Quick Scoop: Dents in fingernails are often called nail pitting or nail ridges , and they can happen for a few different reasons, from harmless trauma to skin or autoimmune conditions. The most common causes include psoriasis , psoriatic arthritis , eczema/dermatitis , alopecia areata , and sometimes injury or repeated pressure on the nail.

Common causes

  • Psoriasis. This is one of the most common causes of nail pitting, and nail changes are common in people with psoriasis.
  • Psoriatic arthritis. Nail pitting can show up with joint symptoms too.
  • Eczema or dermatitis. Inflammation of the skin can affect nail growth and create dents.
  • Alopecia areata and other autoimmune diseases. These can also cause pitting.
  • Trauma or pressure. Repeated nail damage, manicures, or an injury can interrupt normal nail growth and cause dents or horizontal ridges called Beau’s lines.
  • Severe illness or certain treatments. High fever illnesses and chemotherapy can cause nail ridges or dents as well.

What the dent looks like

Small pinhole-like dents are more typical of nail pitting , while longer horizontal dents are more like Beau’s lines. The pattern matters because it can help point to whether the cause is inflammation, illness, or physical injury.

When to get checked

If the dents are new, spreading, painful, affecting multiple nails, or happening with rash, joint pain, or hair loss , it’s worth seeing a dermatologist or clinician. If you want, I can also help you tell the difference between nail pitting, Beau’s lines, and fungal nail changes.