Parrot Beak Nail: Case Report and Review of Parrot Beak Nail Dystrophy

Abstract

Parrot beak nail dystrophy is an excessive forward curvature of the nail plate that can affect both fingernails and toenails. Few cases have been reported since its original description in 1971; however, the incidence is estimated to be 2.5% in healthy individuals. Although the pathogenesis has not yet been established, parrot beak nail has been associated with chronic crack cocaine use, congenital bone or soft tissue abnormalities, other nail dystrophies, peripheral neuropathy, systemic sclerosis, and trauma to the nail. We describe an 86-year-old man with dementia and neuropathy who presented with an unperceived parrot beak nail of his left fourth toenail and concurrent onycholysis of his left great toenail. He had stopped visits with his podiatrist for nail care, which fostered the growth of these nail dystrophies. Our patient's parrot beak nail was successfully treated with nail clipping and regular nail maintenance to prevent its recurrence. The associated conditions, etiologies, and treatment of parrot beak nails are discussed.

Keywords: beak; deformity; digit; dystrophy; finger; nail; onychodystrophy; parrot; toe; treatment.

Figure 1. Parrot beak nail dystrophy of the left fourth toenail

An 86-year-old man presented with a parrot beak nail of the left fourth toe. The nail dystrophy (red circle) was not evident when viewed from the front (A); however, over-curvature was apparent (red arrows) when viewed from the lateral (B) and inferior surfaces (C) of the left foot. Impingement of the nail (D) into the soft pulp of the digit (red arrow) was also observed without surrounding infection or pain.

Figure 2. Onycholysis of the left great toenail and xerosis of the skin concurrent with parrot beak nail of the left fourth toenail

Thickening of the left great toenail with distal onycholysis (white circle) was observed on the same foot as the parrot beak nail (red circle). A pincer nail deformity, demonstrated by pinching of the distal nail bed secondary to excessive transverse nail curvature (black arrows), of the great toenail was noted. In addition, xerosis (white arrows) of the skin on the dorsal foot extending onto the toe and lateral proximal nail fold was present.

Figure 3. Pre-treatment and post-therapy (clipping) of the left fourth toenail of an 86-year-old man with a parrot beak nail deformity

An anterior (A) and inferior (B) view of the parrot beak nail dystrophy (red circle, red arrow) before nail clipping. After treatment (C), there was a residual impression (red arrow) on the soft pulp of the digit without underlying infection. The removed parrot beak nail (D) shows over-curvature from the proximal (white arrow) to the distal (black arrow) nail plate.