The nail disease paronychia is an often tender bacterial or fungal infection where the nail and skin meet at the side or the base of a finger or toenail. It can start suddenly (acute paronychia) or gradually (chronic paronychia).

Description

The cuticle acts as a protective seal, but if it is damaged in any way then bacteria are able to enter the skin and cause infection. Despite the small area affected these infections can be extremely painful as the skin becomes inflamed, hot, red, and throbs continually. Pus is usually present, along with gradual thickening and browning discoloration of the nail plate. If a large amount of pus has collected then it may be necessary to make a little cut in the skin under local anaesthetic to release it.^[1]

When the infection comes on quickly it is usually caused by bacteria. This needs treatment with antibiotics, sometimes in the form of cream, other times with tablets. Chronic paronychia is most often caused by a yeast infection of the soft tissues around the nail but can also be traced to a bacterial infection. If the infection goes on and on then a fungal infection is often the cause and this needs anti-fungal cream or paint to treat it.

Most often it is trauma to the cuticle that allows infection in. Biting or picking at the cuticle, damage through work and overenthusiastic manicuring are the usual culprits. Individuals who work with their hands in water, such as health care workers and food processors, are quite prone to this type of infection. Excess water weakens the seal and soaps or detergents will remove the protective skin oils, leaving the skin dry and more liable to split.

If someone has a cold sore and puts their finger in their mouth then a herpes infection whitlow may appear. Herpes whitlows are frequently found among dentists and dental hygienists.^[2] Prosector's paronychia is a primary inoculation of tuberculosis of the skin and nails, named after its association with prosectors, who prepare specimens for dissection. Paronychia around the entire nail is sometimes referred to as runaround paronychia.

When someone is prone to whitlows it is a good idea for them to use rubber gloves when washing things. In general it is important to moisturise the skin well after having the hands in any water and not to go digging around the cuticle when manicuring the nails.