Pincer Nails

Pincer nails (also called trumpet nails or omega nails) are a complex deformity of the nail plate marked by excessive side-to-side curvature (transverse overcurvature) that increases from the base of the nail toward its free edge. As the nail rolls in, its two lateral edges close together and pinch the soft tissue of the nail bed and the distal phalanx between them, giving the nail the shape of a trumpet or the Greek letter omega (Ω).

Unlike an ordinary ingrown toenail, where only the nail corner digs into the skin, a pincer nail involves the entire nail plate and nail bed. The result is reduced local blood supply, severe pain when walking, thickened keratin under the nail (subungual hyperkeratosis) and deformity of the bone at the tip of the toe.

Pincer nails develop when mechanical forces fall out of balance among three components: the nail plate, the nail bed and the bone of the distal phalanx:

• Traction beneath the nail: The nail bed shrinks or becomes scarred and contracted, so the nail plate loses its flat surface of attachment.
• Deformity of the distal phalanx: Bone spurs (osteophytes) or a bony outgrowth beneath the nail (subungual exostosis) on the distal phalanx push the center of the nail plate upward, forcing both lateral edges to curl down.
• Loss of keratin elasticity: The nail plate thickens and degenerates, loses its natural flexibility and stays permanently locked in its curled shape.

Main Causes

• Hereditary (congenital) pincer nails: These account for a significant share of cases and are inherited in an autosomal dominant pattern. They usually affect both big toes symmetrically, starting at a young age.
• Acquired mechanical causes:
  • Tight closed-toe shoes or high heels that squeeze the toes from side to side for long periods.
  • Cutting the nails deep into the side grooves, which removes the nail plate's natural support.
• Bone and joint disease:
  • Osteoarthritis of the distal joint: Bone spurs on the distal phalanx push the center of the nail plate upward.
  • Subungual exostosis: A benign bony growth that forms beneath the nail bed.
• Skin and systemic disease: Nail psoriasis, chronic fungal nail infection, systemic sclerosis, or side effects of certain medications such as beta-blockers.

Pincer nails are easily mistaken for ordinary ingrown toenails. Repeated nail removals or wedge resections then follow, and each new nail tends to grow back even more curved. At Haute-Derma, every workup includes front and side X-rays of the toe to rule out a bony outgrowth from the distal phalanx, along with measurement of the nail's transverse curvature angle. Our first-line approach is non-invasive nail bracing (orthonyxia) with flexible or metal-alloy braces, which gradually flattens the nail plate without surgery.