• 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.


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)

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

There's more to see -- the rest of this topic is available only to subscribers.