What should you know about onycholysis fungus?

Onycholysis is lifting of the nail plate away from the skin beneath it. The detached area may look white, yellow, or grey because air and debris sit under the nail. Fungus may thicken, discolour, and weaken the nail, while repeated pressure, picking, wet work, psoriasis, or irritation can produce a similar appearance. A clinician may examine the nail and test material before choosing antifungal treatment.

Keep the nail short by trimming only the loose edge, and do not pull the attached portion away. Keep fingers or toes clean and dry, wear protective gloves for prolonged wet work, and avoid sharing nail tools. Pause polish, artificial nails, and harsh removers while the cause is being assessed. Treatment depends on the finding; options may include a prescribed topical or oral antifungal when fungus is confirmed. See [Nail Fungus](/conditions/nail-fungus/) and [Nail Psoriasis](/conditions/nail-psoriasis/) for related causes.

Arrange a clinical assessment if separation is spreading, returns, affects several nails, or does not improve as the nail grows. Seek prompt care for increasing pain, warmth, swelling, pus, bleeding, a dark mark that does not grow out, or separation after a significant injury. A clinician can decide whether specialist treatment such as [Nail Surgery](/treatments/surgical-dermatology/nail-surgery/) is relevant.

Could this be fungus, psoriasis, irritation, or an injury? Is testing needed before treatment? Which products should I stop using, and how should I protect the loose nail while it grows?