Infection of the lateral or proximal nail folds is called paronychia. Acute paronychia is usually caused by Staphylococcus aureus.
Chronic paronychia is caused by many different bacteria and yeasts such as candida.
Pseudomonas is a bacteria that thrives in a warm moist environment. It grows if a space is created between the under surface of the nail plate and the nail bed. The bacteria makes a green pigment and stains the nail plate. The buttons on the left lead to descriptions of these diseases.