What Causes Green Nail Syndrome?

The colour often develops when bacteria multiply in the space between the nail plate and nail bed. Nail separation, also called onycholysis, can follow repeated wetting, minor injury, aggressive manicures, tight footwear, or an underlying nail disorder. The shade may range from pale green to dark green and can remain as the nail grows out. A single discoloured nail is common, although more than one nail can be involved when moisture or trauma affects several nails.

The colour alone does not identify every possible nail problem. A clinician may examine the nail and surrounding skin to distinguish bacterial overgrowth from fungal infection, bruising, medication-related colour change, or another cause.

Keep the affected nail short, clean, and dry. Avoid covering it with polish, artificial nails, or an occlusive dressing while it is discoloured, and do not dig under the nail or pull it away from the nail bed. Wear gloves that allow the hands to dry between wet tasks, and change damp socks or shoes promptly if a toenail is affected.

Arrange a dermatology or primary-care assessment if the colour persists, spreads, or returns. Treatment depends on how much the nail has separated and whether another nail condition is present; a clinician may recommend local care and address the cause of the separation.

Seek prompt medical care for increasing pain, warmth, swelling, pus, a rapidly spreading colour change, or redness extending onto the finger or toe. These findings can signal inflammation or a more active infection. Seek assessment sooner if you have diabetes, reduced circulation, a weakened immune system, or repeated nail infections.

Ask whether the nail has separated, whether testing is needed to rule out fungus, and how to protect the nail while it grows out. Mention recent manicures, nail injury, frequent water exposure, new footwear, skin conditions, and any products used on the nail.