Description

• Onychogryphosis describes claw-like hypertrophy and thickening of the entire nail plate leading to severely distorted, brownish, spiraled nails creating the appearance of a ram’s horn.
• The exaggerated growth of the nail is usually upward/lateral, with superficial transverse striations, and pain can be elicited with applied pressure.

Epidemiology

Prevalence
Onychogryphosis occurs in 5% of the world population.

Etiology and Pathophysiology

• The nail bed matrix produces the nail plate at uneven rates.
• It is thought the faster growing side of uneven keratin production at the nail bed determines the direction of the nail deformity.
• Several potential causes of onychogryphosis (1,2)
  • Pressure or friction from footwear
  • Decreased perfusion secondary to peripheral vascular disorders
  • Onychomycosis
  • Self-neglect (infrequent cutting of nails for an extended length of time)
  • Hallux valgus
• Systemic diseases such as:
  • Ichthyosis
  • Psoriasis
  • Hyperuricemia
  • CNS diseases
  • Syphilis
  • Pemphigus
  • Leishmaniasis
  • Hansen disease
• Autosomal dominant condition, where the nails of the hands and the feet are involved, most notably in the 1st year of life (1)

Genetics
Autosomal dominant in some cases

Risk Factors

• Playing high-friction sports, such as football
• Older individuals
• Dementia
• Homelessness
• Chronic self-neglect
• Subungual epidermophytosis
• Hyperuricemia
• Diabetes mellitus
• Congenital malalignment of the great toenails (CMGT)

General Prevention

• Avoid injuries to the fingers and toes.
• Avoid compact footwear.
• Avoid nail polish because this causes trapping of moisture under the nail.

Commonly Associated Conditions

• Psoriasis
• Ichthyosis
• Onychomycosis
• Hallux valgus
• Diabetes mellitus