Onychogryphosis (ram's horn nail)

Updated 11/1/2022
onychogryphosis, University foot and ankle institute

What is onychogryphosis? 

A type of nail dystrophy, onychogryphosis is the rampant growth of the toenails — most often the big toe. Also called ram’s horn nails, one or more toenails grow considerably faster than the others. Onychogryphosis describes the claw-like hypertrophy and thickening of the entire nail plate.


The afflicted nail frequently exhibits discoloration and hardness.


Onychogryphosis is characterized by an opaque, yellow-brown thickening of the nail plate with elongation and increased curvature. Sometimes the nail growth curves back into the skin and causes an ingrown toenail.

What are the causes of onychogryphosis?

Toenails and fingernails are primarily composed of a protein called keratin. Usually, nails grow one layer at a time in a symmetrical order. Nail changes and abnormalities may provide warning signs when your body is not functioning correctly.


For example:

  • Brittle nails may signal iron deficiency or thyroid disease.
  • Cracks in your nails could mean psoriasis.
  • Kidney disease can cause white lines to form in the nails.
  • Dark lines in the nails can indicate melanoma skin cancer.


It is essential to keep a close eye on your nails and look for unusual changes or growths. Onychogryphosis doesn’t just develop overnight; some cases are the result of years of inadequate personal care.


Who is most at risk of developing Onychogryphosis? 

Though nail disorders can occur at any stage of life, older adults are particularly susceptible. They can sometimes be forgetful, which may make them less vigilant about trimming their nails. Trimming nails can also become difficult due to arthritis or difficulties bending over and reaching the toes.


Onychogryphosis is common in people who live with or have had:

  • poor circulation
  • type 2 diabetes
  • bunions (hallux valgus)
  • gout
  • ichthyosis
  • peripheral vascular disease (PVD)
  • syphilis
  • family background or genetic predisposition
  • pemphigus
  • paronychia


In addition, repeatedly hurting your feet — or minor foot trauma — can damage the toes and nail plates, eventually leading to onychogryphosis.


Does toenail fungal infection cause onychogryphosis? 

Toenail fungus is more than a visual problem; this common infection may lead to severe complications if left untreated — including onychogryphosis.


As many as 50% of patients with onychogryphosis say they had toenail fungus for years before their onychogryphosis developed. Even if toenail fungus wasn’t the primary cause, there’s likely a correlation between the two.


What is the differential diagnosis for onychogryphosis? 

Other diseases have some of the same symptoms as onychogryphosis. Our podiatrists at University Foot and Ankle Institute (UFAI) will look at your all your symptoms and perform in-house diagnostic testing. With this information, we can give you sound medical advice and a diagnosis.


Conditions whose symptoms overlap with onychogryphosis include:

  • congenital malalignment of toenails
  • Pachyonychia congenita
  • Onychomycosis — which can co-exist with onychogryphosis


What is the treatment for onychogryphosis? 

UFAI podiatrists treat foot problems with the goal and minimizing pain and recovery time. Depending on the cause and symptoms, onychogryphosis can be treated conservatively or with surgery. Our goal is to keep your feet healthy and functional and we perfer non-invasive treatment options when possible.


Conservative treatment options 

  • Use mechanical debridement with a nail clipper to shorten the nail and remove subungual hyperkeratosis.
  • Cryotherapy before debridement softens the nail, making it easier to cut.
  • Blunt dissection with a nail clipper after medical nail avulsion.
  • Cauterizing the matrix with phenol.
  • If the cause of the ram’s horn is tight shoes and microtrauma to the nail bed, this can be minimized by changing to adequately fitted footwear.


What are surgical treatments for onychogryphosis? 

If conservative treatment fails, surgical or chemical nail avulsion may be needed. This procedure removes the proximal nail matrix at the base of the nail.


The nail bed deformity is generally treated by first surgically removing the nail. The avulsion of the nail will usually allow the nail bed a chance to repair the damage as it grows a new nail.

  • Surgery may include scalpel excision, cutting electrosurgery, or laser cutting.
  • Ablative techniques include chemical cautery, electrosurgery, or ablative laser.


What is the outcome of onychogryphosis? 

Onychogryphosis typically reappears after conservative treatment. Treatment, however, can be repeated to keep the nail bed short and prevent secondary complications. Use proper footwear to avoid excessive nail pressure on the nail bed.


How to prevent onychogryphosis 

You can do several things to minimize the risk of onychogryphosis and toenail fungus and maintain good nail health.

  • Wash your feet in soap and water regularly. Dry them off with a towel afterward.
  • Keep your feet dry. Change your socks a few times a day, wear cotton socks that remove moisture from your feet, rotate your shoes so they can dry out, and purchase shoes that breathe and don’t constrict your feet.
  • Use foot powder to keep your feet dry.
  • Wear flip-flops or other shower shoes in a locker room or pool.
  • Manicure your nails.
  • Use disinfected tools when trimming your nails.
  • Purchase new shoes after your nail fungus has been cured.


Why trust UFAI for your onychogryphosis treatment? 

It should not be a surprise that foot and ankle pain are widespread. The American Podiatric Medical Association reports that 77% of adults have experienced foot pain, and the pain is constant for 80% of those. 


One of the great things about modern medicine is that our surgical team is well-versed in treating every part of the human body. When it comes to the often-neglected feet, it’s a foot and ankle specialist who will keep you walking strong. That’s where we come in.


With decades of combined experience and the highest success rates in the nation, UFAI providers have treated more than 200,000 patients. We are one of the country's most technologically advanced foot and ankle practices.


UFAI’s surgeons are at the forefront of research, education, product design, regenerative medicine, and foot and ankle care advancements. Our non-profit foundation educates surgical fellows in the advanced foot, ankle treatment, and surgery has performed dozens of clinical trials, and has educated the community for 20 years.


Director Dr. Bob Baravarian — a Board-Certified Podiatric Foot and Ankle Specialist — is one of only a handful of foot and ankle clinicians to have both foot and reconstructive foot and ankle certifications as a Fellow of the American College of Foot and Ankle Surgeons.



Kameyoshi Y, Iwasaki Y, Hide M, Yamamoto S. Congenital onychodysplasia of the index fingers in identical twins. Br J Dermatol 1998;139:1120-2.

Ko D, Lipner SR. Onychogryphosis: Case Report and Review of the Literature. Skin Appendage Disord 2018; 4:326.





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