(See also Overview of Nail Disorders.)
Green nail syndrome is caused by an infection with Pseudomonas species. It usually develops in people who have onycholysis (partial separation of the nail bed from the nail plate or loss of the nail plate) or chronic paronychia and whose hands are often in water or exposed to irritants. The nail in the area of onycholysis becomes greenish in color.
Green nail syndrome may be treated with antiseptics, antibiotics, and sometimes surgical removal of the involved nail.