A nail bed infection (paronychia) is a common nail infection with various causes and symptoms that include soreness and redness around the nail. Sometimes pus causes it to turn a yellow-green color. Paronychia is the most common nail infection. Paronychia is usually caused by bacteria (Staphylococcus aureus).

Greenish staining of human skin may result from a gamut of causes, such as chlorosis, exogenous copper, resolving ecchymosis, drugs, green textile dyes, green tattoos, apocrine and eccrine chromhidrosis, hyper biliverdinemia, chloromas, use of green dyes during tube feeding in patient with multiorgan failure, ...

You may have a green metal box near or in front of your home. These are called padmounted transformers and are a key part of the electrical system that delivers power to your home. They are only found in areas where electric service is buried underground.

It may also occur as transverse green stripes that are ascribed to intermittent episodes of infection. It is usually caused by the bacteria Pseudomonas aeruginosa and is linked to hands being constantly moist or exposed to chemicals, or in individuals who have damaged or traumatised nails.