Green nails are caused by a bacterial infection caused by Pseudomonas aeruginosa and Aspergillus. The bacteria nestles in the gap between the nail and nail bed where it produces a green pigment. It is more common in women whose hands are often in contact with soapy water or detergents but can also occur in professions such as bakers, beauticians and bartenders. Other causes are a condition called onycholysis, unclean nail care equipment and sharing of the same as well as the use of artificial nails.
Pseudomonas is a common household bacteria which can be found in plants, pets, soil and water. Normally the nail, or nail plate, and nail bed are not a hospitable place for the bacteria, but if they have become compromised in some way, then the pseudomonas can find a home. It feeds off the dead tissue in the plate of the nail and this is what causes the separation of the nail and nail bed. The green color is caused by the bacteria infecting the bed of the nail. As well as turning green, the nail may thicken and crumble at the edges and the finger may swell and be painful.
There are rare cases where a fungal infection known as onychomycosis is the cause of green nails. This condition becomes increasingly common as a person ages and it rarely affects children. Onycholysis occurs when a fingernail or toenail becomes loose and separates from the nail bed. This may happen because of repetitive trauma, damage due to manicure tools and a prolonged immersion in water, among others. As there are many causes, a doctor may want to check for skin problems or medical conditions like thyroid disease.
The application of artificial nails can also cause green nail syndrome. The technician applying the nail must clean and disinfect the nail surface before application. If an artificial nail is applied over a surface where there is pseudomonas bacteria, then the resulting virtual oxygen free environment will enable the bacteria to thrive. It then eats the oils and the byproduct is what causes the green color.
Green nails treatment is usually a topical antibiotic to treat the infection. Nails should be kept short to enable the medication to reach the nail more easily. Treatment should take about two or three weeks. The condition can be avoided by the wearing of gloves if hands are constantly in contact with water. Alternative treatments include plant-derived natural oils such as tea tree oil. Tea tree oil has anti-bacterial as well as anti-fungal properties so it is effective for both causes of green nails. Soaking nails in alcohol a few times a day may also help.