Onychauxis is a uniform hypertrophy or thickening without deformity of whole nail plate. The thickening occurs at matrix and it is thought that trauma to the nail matrix results in increased production of onchyocytes. If there is a deformity of the nail plate with thickness, then that is called onychogryphosis. Onychauxis is common and in some settings is abbreviated as ‘O/X’ in clinical notes.
Maybe associated with minor repetitive trauma to the nail (eg wearing tight fitting shoes) or acute trauma. There may be a mallet toe present that exposes the toe nail to distal pressure on the ground. May be caused by a fungal infection or an underlying condition such a psoriasis or eczema. Poor circulation in the elderly has been associated with it. There was an old case reported of hypogonadism whose onychauxis reversed when androgen levels were restored (Lisser, 1924). It is also seen in Hansen’s disease (leprosy).
Nail appears more opaque than normal translucent pink appearance – may have a light brown discoloration.
Subungual hyperkeratosis and debris is common.
Most commonly, the hallux and fifth toenails ares involved – but others can be involved (all nails or isolated nails).
Nail cutting is difficult and often neglected.
Shoe pressure may cause pain.
Pressure may result in a subungual aseptic necrosis.
Management of Onychauxis:
As damage to the nail matrix is irreversible, there needs to be regular reduction of nail plate with nail cutters and nail drill/burr
Check footwear fitting for pressure on the toenails.
Those with an underlying skin condition may see an improvement in the onychauxis when there is an improvement in the skin condition.
Maybe permanent surgical removal of the nail if particularity problematic.
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