Onycholysis

Onycholysis denotes the separation of nail plate from the nail bed at its distal and lateral attachments. Total separation of the nail bed is termed onychomadesis (1).

It is said to occur particularly at the ring finger, but can occur on all fingernails, and is apparently due to sympathetic overactivity. It is uncommon.

Although it is not a disease of the nail matrix, secondary infection may cause nail discolouration which can be seen underneath the nail (1).

Causes include:

• thyrotoxicosis - known as Plummer's nails; the free edge of the nail becomes undulated and curves upwards (1)
• psoriasis
• fungal nail infection - usually by Candida albicans; mostly in women; green colouration
• space occupying lesion e.g. tumour
• trauma
• occupation - especially if there is constant wetting of the nails
• Raynaud's disease
• phototoxic reaction to tetracyclines

Reference:

• (1) Gregoriou S et al. Nail disorders and systemic disease: What the nails tell us. JFP 2008; 57(8)