A paronychia is an infection or abscess of the tissues around the base and along the sides of the nail plate. It is the most common infection in the hand.1 A paronychia can be located on the fingers or the toes. It occurs in all age groups. It can cause significant pain and discomfort leading to a visit to the Emergency Department.
A paronychia initially presents with redness, swelling, and tenderness along the edges of the nail plate. This can progress to an abscess that requires drainage. An infection that extends to the overlying proximal cuticle is termed an eponychia. This chapter discusses the treatments, which vary with the extent and the location of the infection.
The dorsal aspect of the distal digit consists of the nail plate, the nail bed (matrix), and the perionychium (Figure 107-1). The nail bed is situated beneath the nail plate and is responsible for growth of the nail. The perionychium consists of the soft tissue surrounding the nail plate (eponychium and lateral nail folds).
The distal finger illustrating a paronychia and the surface anatomy.
A paronychia is usually the result of frequent trauma, tight fitting apparel (e.g., gloves, pantyhose, and shoes), aggressive manicures, the use of artificial nails, hangnails or ingrown nails, or nail biting.2 A disruption of the seal between the nail plate and nail fold allows bacteria to enter, leading to pus formation in the eponychial space (Figure 107-1). It begins as a swelling and erythema in the dorsolateral corner of the nail fold that can progress to an abscess. A paronychia can grow and spread to adjacent structures and result in a felon, an osteomyelitis, or a tenosynovitis. Many paronychias are polymicrobial, containing both aerobic and anaerobic organisms.14 The most common organism to cause a paronychia is Staphylococcus aureus.3 In children and nail biters, paronychias are often caused by anaerobes secondary to finger sucking or nail biting.4 Gram-negative organisms should be considered in immunocompromised hosts. Chronic paronychias are the result of separation of the nail from the nail plate, which leaves a space for bacteria and fungi to collect.12 These infections are usually caused by Candida albicans.5
An early paronychia with signs of cellulitis may be treated nonsurgically. This requires frequent warm soaks (e.g., water, vinegar, or Burow's solution), immobilization, elevation, topical antibiotics (e.g., bacitracin or Mupirocin) with or without topical corticosteroids, and follow-up in 24 hours.2,6,11,12 Paronychia resistant to these measures should be treated with oral antibiotics to cover Staphylococcus, plus anaerobic coverage if nail biting or finger sucking were causative agents.12 Amoxicillin/clavulanate, clindamycin, and trimethoprim-sulfamethoxazole are commonly used antibiotics. Take into account the prevalence of methicillin-resistant Staphylococcus aureus in your community when deciding upon the choice ...