Paronychia is an inflammation of the skin around the nail, which can occur suddenly, when it is usually due to the bacterium Staphylococcus aureus, or gradually when it is commonly caused by the fungus Candida albicans. The term is from Greek: παρωνυχία from para around, onyx nail, and the abstract noun suffix -ia.Risk factors include repeatedly washing hands and trauma to the cuticle such as may occur from repeated nail biting or hangnails. Treatment includes antibiotics and antifungals, 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 bacterium Staphylococcus aureus, or gradually (chronic) when it is commonly caused by Candida albicans.The term is from Greek: παρωνυχία from para, "around", onyx, "nail" and the 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. It is often treated with antibiotics, either topical (applied to the skin) or oral (taken by mouth), 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.
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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. : 660  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. : 343  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:
Candidal paronychia is an inflammation of the nail fold produced by C. albicans. : 310 
Pyogenic paronychia is an inflammation of the folds of skin surrounding the nail caused by bacteria. : 254  Generally, acute paronychia is pyogenic, as it is usually caused by a bacterial infection. Differential
Differential diagnosis of paronychia includes:

Cellulitis is a superficial infection and presents as erythema and swelling to the affected portion of the body with no area of fluctuance. Treatment is with oral antibiotics. Whitlow or felon is a subcutaneous infection of the digital pulp space. The area becomes warm, red, tense, and very painful due to the confinement of the infection, creating pressure in the individual compartments created by the septa of the finger pad. These require excision and drainage, usually with a longitudinal incision and blunt dissection to ensure adequate drainage. Herpetic whitlow is a viral infection of the distal finger caused by HSV.