This elderly man had noticed the discolouration and thickening of the nails of both of his big toes for several years.
Initially he attended his GP who, thinking it was a fungal nail infection, had prescribed tioconazole solution twice a day.
After a year, there had been no improvement and the patient gave up, thinking he just had to live with it. However, when the nail began to cut into the adjacent toe he sought further help.
- What is the diagnosis, management and differential diagnosis?
Diagnosis and management
The most likely diagnosis in this case is onychogryphosis, a hypertrophy of the nail in which the nail becomes thickened and discoloured.
Deformity develops as one side of the nail grows slower than the other so that it assumes the shape of a ram's horn. The big toenails are most commonly affected. Onychogryphosis usually follows injury, such as a heavy object falling on the nail.
General advice about footwear can be helpful and regular trimming and filing by the chiropodist may be sufficient. In more severe cases, surgical avulsion of the nail under local anaesthetic with ablation of the nail bed is necessary. If remnants of the nail matrix are left there is the risk of regeneration of the nail. A saturated solution of phenol is often now used to achieve this.
Possible different diagnoses
- Fungal infection of the nail
- Psoriasis, eczema
- Old age, due to impairment of peripheral circulation
Fungal infection of the nail:
- May be caused by a dermatophyte such as Trichophyto rubrum, yeast such as Candida albicans or mould such as fusarium species.
- One or more nails may be affected - most commonly the big toenail.
- Nail discolouration - yellow, white or brown.
- Destruction of the nail.
- Confirm the diagnosis before treatment for microscopy and culture.
Contributed by Dr Jean Watkins, a sessional GP in Hampshire.