Paronychia

Paronychia is an inflammation of the skin around the nail, which can occur suddenly, when it is usually due to the bacteria "Staph. aureus", or gradually when it is commonly caused by "Candida albicans". The term is from from "para", "around", "onyx", "nail" and the abstract noun suffix "-ia".
The index and middle fingers are most commonly affected and usually present with redness, swelling and pain. Pus or discharge may be present. 
Risk factors include repeatedly washing hands and trauma to the cuticle such as may occur from repeated nail biting, or hangnails.
Treatment ranges from antibiotics and anti-fungals, and if pus is present, the consideration of incision and drainage.
Paronychia is commonly misapplied as a synonym for herpetic whitlow or felon.
Definition and etymology.
Paronychia is an inflammation of the skin around the nail, which can occur suddenly (acute), when it is usually due to the bacteria "Staph. aureus", or gradually (chronic) when it is commonly caused by "Candida albicans".
The term is from from "para", "around", "onyx", "nail" and the abstract noun suffix "-ia".
Signs and symptoms.
The index and middle fingers are most commonly affected and may present with redness, swelling and pain. Pus or discharge may be present.
Causes.
Acute paronychia is usually caused by bacteria. Paronychia is often treated with antibiotics, either topical or oral or both. 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 is continuous, the cause is often fungal and needs antifungal cream or paint to be treated.
Risk factors include repeatedly washing hands and trauma to the cuticle such as may occur from repeated nail biting. or hangnails. In the context of bartending, it is known as "bar rot".
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".
Painful paronychia in association with a scaly, erythematous, keratotic rash (papules and plaques) of the ears, nose, fingers, and toes may be indicative of acrokeratosis paraneoplastica, which is associated with squamous cell carcinoma of the larynx.
Paronychia can occur with diabetes, drug-induced immunosuppression, or systemic diseases such as pemphigus.
Diagnosis.
Types.
Paronychia may be divided as occurring suddenly, acute, or gradually, chronic.
Acute.
Acute paronychia is an infection of the folds of tissue surrounding the nail of a finger or, less commonly, a toe, lasting less than six weeks. The infection generally starts in the paronychium at the side of the nail, with local redness, swelling, and pain. Acute paronychia is usually caused by direct or indirect trauma to the cuticle or nail fold, and may be from relatively minor events, such as dishwashing, an injury from a splinter or thorn, nail biting, biting or picking at a hangnail, finger sucking, an ingrown nail, or manicure procedures.
Chronic.
Chronic Paronychia is an infection of the folds of tissue surrounding the nail of a finger or, less commonly, a toe, lasting more than six weeks. It is a nail disease prevalent in individuals whose hands or feet are subject to moist local environments, and is often due to contact dermatitis. In chronic paronychia, the cuticle separates from the nail plate, leaving the region between the proximal nail fold and the nail plate vulnerable to infection. It can be the result of dish washing, finger sucking, aggressively trimming the cuticles, or frequent contact with chemicals (mild alkalis, acids, etc.).
Alternatively, paronychia may be divided as follows:
Differential.
Differential diagnosis of paronychia include:
Treatment.
When no pus is present, warm soaks for acute paronychia are reasonable, even though there is a lack of evidence to support its use.
 Chronic paronychia is treated by avoiding whatever is causing it, a topical antifungal, and a topical steroid. In those who do not improve following these measures, oral antifungals and steroids may be used or the nail fold may be removed surgically.
Antibiotics.
There is no strong evidence recommending topical vs. oral antibiotics, and this may be physician-dependent based on experience. Antibiotic used should have staph aureus coverage. Topical antibiotics used may be a triple antibiotic ointment, bacitracin, or mupirocin. In patients failing topical treatment or more severe cases, oral antibiotics are an option; dicloxacillin (250mg four times a day) or cephalexin (500mg three to four times a day). Indications for antibiotics with anaerobic coverage include patients where there is a concern for oral inoculation; this would require the addition of clindamycin or amoxicillin-clavulanate.
Antibiotics such as clindamycin or cephalexin are also often used, the first being more effective in areas where MRSA is common. If there are signs of an abscess (the presence of pus) drainage is recommended.
Epidemiology.
Paronychia is more common in women than in men, with a female-to-male ratio of three to one. Usually, they affect manual labor workers or patients in occupations that require them to have their hands or feet submerged in water for prolonged periods (e.g., dishwashers). Middle-aged females are at the highest risk of infection.