Paronychia Drainage

Excerpt

Acute paronychia is one of the most common infections of the hand. It is usually caused by a breakdown of the seal between the nail plate and the nail fold with infection resulting from subsequent inoculation of bacterial or fungal pathogens. This is typically precipitated by nail-biting, trauma, manicures, ingrown nails, and hangnail manipulation. Abscess involving pus within the soft tissues adjacent to the nail may occur, indicating the need for surgical drainage.

From a microbiology perspective, paronychia of the hand is reported to be a polymicrobial infection with mixed aerobic and anaerobic bacterial flora in around 50% of cases. The most common infective pathogen is Staphylococcus aureus (including methicillin-resistant Staphylococcus aureus (MRSA)), but other aerobic bacteria may include Streptococcus species or gram-negative bacteria. While anaerobic florae such as Bacteroides, Enterococcus species, or Eikenella corrodens are associated with exposure to oral secretions through nail-biting and digital sucking practices (more common in children). Clinical history and local antibiotic guidance, including consideration of MRSA rates, should direct the prescription of antibiotics. Non-bacterial infections are less common but may include fungal infections such as Candida albicans and viral infections such as herpes simplex.

If a paronychia has been present for less than six weeks, it is classified as acute, whereas those present for six weeks or more are classified as chronic. Chronic paronychia is a multifactorial inflammatory condition primarily caused by exposure to environmental allergens or irritants. The disruption to the protective barrier caused by this inflammatory process may result in colonization with bacterial or fungal organisms. Candida albicans is the most commonly implicated micro-organism. With differing etiologies and treatment approaches, chronic paronychia should be considered a separate entity from acute paronychia, which is the focus of this article.

Another important differential diagnosis is herpetic whitlow, a herpes simplex virus infection that may manifest clinically with the presence of blisters involving the distal phalanx. Surgical drainage is contraindicated unless a concurrent bacterial infection is present.

Paronychia involving toes is a relatively common condition and may be associated with ingrowing toenails. Although treatment approaches may be similar, the focus of this article is the management of acute paronychia drainage of the hand.

Clinical Assessment and Diagnosis

Acute paronychia is diagnosed clinically with pain, swelling, and erythema of the nail folds. Formation of pus along the paronychial fold may occur; if untreated, an abscess may progress to involve the eponychium and the area below the nail plate. This can generally be identified by the presence of a tender, boggy swelling. As described by Turkmen et al., the digital pressure test can also be used to evaluate the presence of pus within the soft tissue. If light pressure is applied to the volar aspect of the tip of the affected digit, a localized region of skin blanching around the nail may indicate the presence of an underlying abscess. Furthermore, if pus is deep to the nail plate, it may be visible on inspection and ballotable on palpation.

A felon is an infection in the pulp of the distal phalanx of a digit and is a separate condition from paronychia. Although a paronychia can lead to the development of a felon, the presence of one does not indicate the presence of the other. Careful examination of the digit should be performed to identify the clinical presence of a felon and thus the need for surgical drainage. This is characterized by a tender, fluctuant swelling involving the pulp of the digit. This article will only discuss acute paronychia drainage.

In the early stage of paronychia, inflammation of the paronychial fold alone may be present, without pus formation. The majority of such cases may be managed non-operatively in the primary care or emergency department setting. Treatment involving oral antibiotics with close monitoring comprising follow-up appointments and patient safety advice is recommended. Oral antibiotics with gram-positive coverage are advised, or if suspecting exposure to oral bacteria, a broad-spectrum agent is preferable. Although some authors recommend using antiseptic or warm water soaks, there is no clear evidence to recommend their use routinely in any stage of the condition.

In the later stage of paronychia, the presence of pus in the form of a local abscess may be present. Laboratory and radiological investigations are important in this stage. Plain film radiographs of the involved digit are used to investigate the possibility of associated foreign bodies, fractures, or osteomyelitis. Glucose testing is important to review glycemic control in patients with diabetes and may occasionally identify undiagnosed diabetes. Extended laboratory blood tests such as full blood count and inflammatory markers are generally only indicated in more severe cases where marked cellulitis or tracking lymphangitis is present. In all cases of paronychia with abscesses, surgical drainage is indicated. This may be performed in primary care or emergency department settings depending on local resources and expertise. Referral to tertiary hand surgery may otherwise be required.