Onyxis is a condition in which a part (usually the corner) of the nail enters the skin of the big toe. It can also emerge on the other toes and very rarely on the fingers.
 
It can be due to a direct injury to the toe that causes the corners of the nails to turn to the skin, to a genetic predisposition, to poor nail care, to narrow shoes or to continuous and recurring minor nail injuries (athletes).
 
The entry of the nail into the skin causes injury and thus entry of germs into the skin, resulting in local inflammation of the nail. Abscess formation, pus emission or, in neglected cases, hypertrophic granular tissue formation may also occur.
 
Symptoms include redness, swelling of the skin, pang or pus emission.
Treatment can be conservative or surgical.
Conservative treatment includes:

• Pediluviums in hot water with local antiseptics 2 or 3 times a day
• Keeping the foot dry during the rest of the day
• Avoiding closed shoes
• Oral administration of antibiotics
• Avoiding the use of topical antibiotic ointments

 
The surgical treatment can be the resection of the affected part of the nail with co-resection of the granular tissue of the paronych (partial onychotomy), the resection of the whole nail (total onycectomy), the removal of the nail with removal of the uterus-root behind and below the recurvation of the skin on the nail (radical onychotomy). The last operation prevents the future development of part or all the nail.

Radical Onychectomy can be performed with laser diode with very good and permanent results.