Chapter 107. Paronychia or Eponychia Incision and Drainage

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).

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 of antibiotic.

A progression of the infection results in fluctuance and the formation of an abscess. The digital pressure test may be used to diagnose the presence of an abscess when the exam is otherwise equivocal. Instruct the patient to oppose the thumb and affected finger and apply light pressure to the distal volar aspect of the affected digit. If an abscess is present, the skin under the nail plate will blanch.10 The presence of an abscess, fluctuance, or pus beneath the nail plate requires an incision and drainage procedure. This procedure will relieve the patient's pain, promote healing, and prevent complications from local extension into surrounding bone and soft tissues.

A herpetic whitlow is a herpes simplex virus infection of the distal phalanx that can be confused with an early paronychia or felon. The presence of multiple clear vesicles that coalesce suggests a herpetic whitlow. The herpetic whitlow is a nonsurgical and self-limited infection. Treatment consists of a dry dressing to the affected finger in order to prevent autoinoculation and transmission of the infection, oral antiviral agents, and analgesics. Incision and drainage is not recommended, will prolong the recovery, and lead to secondary bacterial infection.7 A chronic paronychia should be referred to a Hand Surgeon or Dermatologist for treatment.

• Povidone iodine or chlorhexidine solution
• Sterile gloves
• #11 scalpel blade or an 18 gauge needle
• Local anesthetic solution without epinephrine
• 18 and 27 gauge needles
• 5 to 10 mL syringe
• Ethyl chloride spray
• Forceps
• Mosquito hemostat
• Ribbon-gauze packing, ½ in. wide
• Petrolatum gauze, ½ in. wide
• Scissors
• 4 × 4 gauze squares
• 18 gauge angiocatheter
• 20 mL syringe
• Sterile saline
• Adhesive tape

Explain the procedure, its risks, and benefits to the patient and/or their representative. Obtain an informed consent for the procedure. Assess and update the patient's tetanus immune status if indicated. Place the patient on a gurney with the extremity on a bedside procedure table in a well-lit room. Soak the digit in warm water for 5 minutes to soften the skin. Perform a digital nerve block if the patient is apprehensive, has significant tenderness, or if it is not a simple paronychia or eponychia. Refer to Chapter 126 for the complete details regarding digital anesthesia techniques. Alternatively, apply ethyl chloride spray to the area until the skin turns frosty and pale. Apply povidone iodine or chlorhexidine solution circumferentially to the distal digit and allow it to dry. The digit can be secured to a sterile tongue depressor for better control, especially in uncooperative children.

Simple Paronychia or Eponychia

There is no need for a skin incision in an uncomplicated paronychia or eponychia. Simply lifting the eponychium off the nail plate at the point of maximal tenderness and/or fluctuance is usually curative. Slide the tip of a #11 scalpel blade (or an 18 gauge needle) under the paronychia, or eponychia, at the site of maximal fluctuance (Figure 107-2). Advance the scalpel blade to lift the soft tissue from the nail plate until there is an efflux of purulent fluid. Apply digital pressure to the area to express the pus. Gently place a hemostat under the soft tissue to break any loculations. Irrigate the pocket with an angiocatheter on a syringe containing sterile saline.

Packing a paronychia is controversial and physician-dependent. Place a small piece of ribbon gauze or petrolatum gauze under the elevated soft tissue followed by a simple dressing. If packing is not performed, apply an antibiotic ointment followed by a simple dressing or bandage. Oral antibiotics are not recommended for an uncomplicated paronychia or eponychia.

Paronychia with Extension under the Lateral Nail Plate

A more extensive incision and drainage is required when pus accumulates laterally and beneath the nail plate. Remove the lateral nail plate to allow adequate drainage (Figure 107-3A). Use scissors to cut the nail plate longitudinally. Aim the point of the scissors upward and against the undersurface of the nail plate to prevent injuring the nail bed. Remove the lateral nail plate with a hemostat. A small (2 to 3 mm) incision may be required in the corner of the nail fold to remove the nail plate (Figure 107-3A). This will result in the egress of pus. Irrigate the area with saline. Insert a small piece of petrolatum gauze under the nail fold (Figure 107-3B). This will prevent the nail fold from fusing to the nail bed.

Paronychia with Extension under the Proximal Nail Plate

A paronychia with extension under the proximal nail plate also requires the removal of a portion of the nail plate (Figure 107-4). Make two 3 to 4 mm long incisions at the corners of the nail folds (Figure 107-4A). Cut the proximal one-third of the nail plate with scissors (Figure 107-4B). Aim the point of the scissors upward and against the undersurface of the nail plate to prevent injuring the nail bed. Grasp and remove the proximal segment of the nail plate with a hemostat. This will result in the egress of pus. Irrigate the area with saline. Insert a piece of petrolatum gauze under the nail fold to prevent it from fusing to the nail bed (Figure 107-4C).

Removal of the entire nail is rarely necessary except in the case of an extensive subungual abscess. An alternative to nail removal is trephination with a heated paper clip or a microcautery unit.8 A large opening or multiple holes are required with this technique in order to eliminate the pus. Refer to Chapter 102 for the complete details regarding trephination.

Chronic Paronychia

A chronic paronychia occurs from recurrent episodes of inflammation or from neglected infections. It is much more difficult to treat and eradicate than an acute infection. A chronic paronychia is seen frequently in immunosuppressed patients, such as those with diabetes or cancer. These effects are due to the disease process, such as in diabetes, or due to effects of treatment, as seen with certain HIV drugs and chemotherapeutic agents.12 A chronic paronychia is also common in people who wash their hands often, such as dishwashers and healthcare providers. It can also be due to frequent contact with chemicals, finger biting or sucking, and cuticle trimming. The most frequently isolated organism is C. albicans, which commonly coexists with S. aureus.5,6 Initial treatment typically includes avoiding the noxious exposure, topical emollients, and antifungals.13 Definitive treatment for a chronic paronychia is eponychial marsupialization. This involves removal of a crescent-shaped piece of skin proximal to the nail fold and parallel to the eponychium, extending from the radial to ulnar borders. In addition to marsupialization, complete or partial nail removal may be necessary if nail ridging is present.9 A chronic paronychia may be confused with another condition that looks similar and mimics a chronic paronychia such as cysts, foreign body reactions, malignancies, psoriasis, and verrucae. Refer all chronic paronychia to a Hand Surgeon due to the higher rate of recurrence, the complexity in management, and where follow-up care can be more consistent.

Immobilize and elevate the digit. Instruct the patient to avoid nail biting or sucking. Any discomfort can be treated with acetaminophen or nonsteroidal anti-inflammatory medications. Follow-up care in 24 hours is important as complications can occur despite proper Emergency Department management. Packing of a simple paronychia should be removed in 24 hours. Warm soaks can begin immediately if packing is not placed. Otherwise, warm soaks should be delayed until the packing is removed in 24 hours. There is no evidence that oral antibiotics improve outcome after the incision and drainage of a simple and uncomplicated paronychia. Oral antibiotics are not necessary unless the nail bed is involved, there is apparent cellulitis of the surrounding tissue, or if there are systemic signs of infections such as lymphangitis and fever.6 Patients should return to the Emergency Department if they develop a fever, reaccumulation of pus, redness extending up the finger and hand, or increased tenderness to the digit.

Most simple paronychias resolve within a few days. If they persist longer or recur, consult a Hand Surgeon for more aggressive management, such as eponychial marsupialization and nail plate removal.

Paronychia or eponychia that extend under the nail plate require follow-up in 24 hours. The packing must be maintained between the nail fold and the nail bed for at least 5 to 7 days. The nail fold will fuse to the nail bed if the packing is removed too soon and a new nail plate will not form. These infections require a 5 to 7 day course of oral antistaphylococcal antibiotics. Nonsteroidal anti-inflammatory medications supplemented with occasional narcotic analgesics will provide adequate pain control for these patients.

Complications, even in a properly drained paronychia, include a felon, osteomyelitis of the distal phalanx, and a tenosynovitis. Superinfection with C. albicans or other fungi can also occur. These complications can be due to the paronychia itself or from an inadequate incision and drainage procedure.

Complications from the incision and drainage procedure are rare if it is properly performed. Care must be taken if the lateral or proximal nail plate is removed to avoid damaging the underlying matrix so that a nail deformity does not result. Fusion of the nail fold to the nail bed will result in a new nail not being formed. Inadequate drainage can result in the infection spreading to adjacent bone and soft tissues. Incision of the skin instead of elevating it off the nail plate can result in prolonged healing.

A paronychia is one of the most common hand infections. The treatment depends on the extent and location of the infection. The incision and drainage procedure is quick, simple, and easy to perform. Simple paronychias require elevation of the nail fold with no incision. A more extensive incision and drainage is required along with nail excision when pus accumulates below the nail plate. Follow-up is critical as complications may occur, even when the Emergency Department treatment is optimal.