Onychogryphosis

Onychogryphosis is a nail dystrophy characterized by thickened, curved nails, most often affecting the toenails. The nail plate becomes hypertrophied and develops an irregular, claw-like deformity that can resemble a ram's horn. The condition is usually acquired and commonly involves the great toe, though any nail can be affected.

Etiology and risk factors include a multifactorial background. Age-related nail changes, peripheral vascular disease, diabetes mellitus, and neuropathy increase risk. Recurrent trauma or neglect of nail care, persistent pressure from ill-fitting footwear, and prior nail disease such as onychomycosis or psoriasis can contribute. Congenital cases are rare.

Clinical features encompass a thick, hard, and curved nail with increased transverse and longitudinal curvature. The edge may overgrow and become irregular; debris may accumulate under the nail, and subungual infection can occur. Pain or tenderness and difficulty wearing shoes may be present.

Diagnosis is typically clinical, based on history and examination. Imaging, such as X-ray or MRI, may be used to assess underlying bone deformities before surgical planning. Differential diagnoses include pincer nails, onychomycosis, and subungual exostosis. Microbiological testing can identify coexisting fungal infection.

Management aims to relieve pain, improve function, and reduce recurrence. Mild cases are managed with careful trimming, thinning, keratolytic agents, and education on proper nail care and footwear. Treatment of any fungal infection is important. More severe cases may require professional debridement, partial nail avulsion, or total nail avulsion with matrixectomy to prevent regrowth. Addressing underlying conditions such as diabetes or vascular disease is important. Regular follow-up is needed due to recurrence risk.

Prognosis varies; with appropriate care, symptoms can be controlled and function preserved, but recurrence is common without addressing contributing factors.