Pathology Spotlight: Onychogryphosis

Onychogryphosis, or Ram’s Horn Nail, is a condition in which there is abnormal nail growth. It causes the nail to become very overgrown, often resembling a ram’s horn, as the name suggests. While it can affect any nail of the fingers and toes, it is most commonly seen in big toe.

There is no singular cause of onychogryphosis. Trauma to the nail bed is one of the most common causes, coming from either injury or overly restrictive footwear. Footballers and rugby players are at high risk due to this. Poor posture may lead to stress on the base of the nail causing onychogryphosis. Fungal infection of the foot may also act to overstimulate nail growth. People with poor circulation or diabetes are more at risk as these can affect the ability of trauma or infection of the foot to heal. Poor hygiene or failure to trim the nails regularly can also be a factor, and as the affected nails then become difficult to trim this can then exacerbate the condition.

Diagnosis is usually by simply examining the nail itself. The nail becomes thick, long and curved as it grows, as can be seen in our example, which comes from a big toe. The base of the nail becomes thickened and tender to pressure. If the cause is a fungal infection the nail will often become slightly crumbly, and take on a yellowish discolouration. This can have a secondary impact on ability to walk and posture, and the curvature of the nails may cause pressure on adjacent toes.


A Ram’s Horn toenail in our collection. The toenail is 6cm long.

Treatment can be as simple as grinding the nail down and taking preventative measures to prevent recurrence such as wearing well-fitting shoes and practicing good foot hygiene with regular nail trimming. In more advanced cases there may need to be surgical removal of the nail bed, along with treatment with either lasers or phenol to destroy the germinal matrix of the nail. These cells are responsible for new nail growth so without full destruction irregular spikes of new growing nail are likely.

Image from WikiDoc:

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