Onycholysis is when the nail plate separates from the nail bed. It usually presents as the nail lifting away from the underlying skin, starting from the tip. During this separation, the underside of the nail appears white or grey, and there can sometimes be a build-up of dirt or an unpleasant odour.
Causes of onycholysis include trauma, fungal infections, psoriasis, thyroid conditions, certain medications, and prolonged exposure to water or chemicals.
In treatment, it's important to identify and remove the underlying cause, protect the nail from trauma, and maintain hygiene. Where necessary, topical or systemic treatment can be planned by a dermatologist.