Green nail syndrome affecting a patients thumb nail and onycholysis affecting the other nails. Green nail syndrome, or chloronychia, is caused by infection with the bacterium Pseudomonas aeruginosa. It is most common in those whose hands are constantly exposed to water or detergents. Treatment for green nail syndrome is with antibiotics and keeping the nail dry. Onycholysis is the painless loosening or detachment of the nail from the nailbed. It is a risk factor for green nail syndrome.