February 20, 2009 — A review published in the February 15 issue of American Family Physician discusses risk factors, conservative therapy, and surgical approaches regarding management of the ingrown toenail in primary care.

"Approximately 20 percent of patients presenting to a family physician with a foot problem have an ingrown toenail, also known as onychocryptosis," write Joel J. Heidelbaugh, MD, and Hobart Lee, MD, from the University of Michigan in Ann Arbor. "Ingrown toenails occur when the periungual skin is punctured by its corresponding nail plate, resulting in a cascade of foreign body, inflammatory, infectious, and reparative processes. Ultimately, this may result in a painful, draining, and foul-smelling lesion of the involved toe (most commonly, the hallux nail), with soft tissue hypertrophy around the nail plate."

Anatomic and behavioral factors that may predispose to onychocryptosis may include incorrect methods of nail trimming, repetitive or unintentional trauma, genetic risk factors, hyperhidrosis, and poor foot hygiene. Wider nail folds and thinner, flatter nails are thought to increase the risk for ingrown toenails, but this is still unproven.

To help prevent onychocryptosis, toenails should be cut straight across and not pointed or too short, and the corners should not be rounded off.

Medical conditions associated with onychocryptosis include diabetes, obesity, as well as thyroid, cardiac, and kidney diseases that may predispose to lower extremity edema.

Ingrown toenail can be characterized as mild to moderate, in which the lesion gives rise to minimal to moderate pain with pressure, little erythema, and no purulent drainage. Mild cases are associated with nail-fold swelling and edema, and moderate cases with increased swelling, possible seropurulent drainage, infection, and ulceration of the nail fold.

Moderate to severe ingrown toenail is associated with severe, disabling pain, marked erythema, and purulent drainage. In the most severe cases of onychocryptosis, there is chronic inflammation, granulation, and marked nail-fold hypertrophy. Even for moderate to severe lesions, antibiotic use is not routinely recommended because it has not been shown to decrease healing time, postoperative morbidity, or recurrence rates.

Indications for the treatment of ingrown toenail include significant pain or infection; deformed, curved nail known as onychogryposis; or chronic, recurrent nail-fold inflammation (paronychia).

Conservative approaches to therapy are appropriate for initial management of mild to moderate ingrown toenail. These may include foot soaks in warm, soapy water and application of topical antibiotic ointment or mid-potency to high-potency steroid cream or ointment; placement of cotton wisps or dental floss under the edge of the ingrown toenail; and gutter splinting, which may sometimes involve the placement of a sculptured acrylic nail.

When conservative therapy fails for initial management of moderate to severe onychocryptosis, surgical treatments may be appropriate, such as partial nail avulsion or complete nail excision with or without phenolization. For treatment of ingrown toenails, partial nail avulsion followed by either phenolization or direct surgical excision of the nail matrix is equally effective.

For the prevention of symptomatic recurrence of ingrown toenails, partial avulsion of the lateral nail plate plus phenolization has been shown to be more effective than surgical excision of the nail without phenolization. However, the risk for postoperative infection is slightly increased with avulsion plus phenolization. Administration of oral antibiotics before or after phenolization has not been shown to improve outcomes.

When there is postoperative recurrence with pain and infection, the germinal matrix tissue should be permanently destroyed with phenolization (application of 80% - 88% phenol solution), electrocautery, radiofrequency, or carbon dioxide laser ablation of the the nail matrix.

Contraindications to surgical therapy include allergy to local anesthetics, bleeding disorder, or pregnancy if phenol use is considered.

All patients undergoing toenail surgery should receive appropriate education regarding postoperative care.

Specific recommendations for clinical practice, and their accompanying level of evidence rating, are as follows:

• For the treatment of ingrown toenails without infection, conservative approaches include use of a cotton wisp, dental floss, or gutter splint (with or without acrylic nail) under the lateral edge of the ingrown nail (level of evidence, C).
• Before or after phenolization, administration of oral antibiotics does not decrease healing rates or rates of postprocedure morbidity (level of evidence, B).
• For the treatment of onychocryptosis, partial nail avulsion followed by phenolization or direct surgical excision of the nail matrix is equally effective (level of evidence, B).
• Partial nail avulsion combined with phenolization is more effective at preventing symptomatic recurrence of ingrown toenails vs surgical excision of the nail without phenolization, but it carries a slightly increased risk for postoperative infection (level of evidence, B).

"Overaggressive electrocautery or radiofrequency ablation to the nail matrix may damage the adjacent and underlying fascia or periosteum," the review authors conclude. "If the toe is healing poorly several weeks after the procedure, debridement, oral antibiotics, and radiographic evaluation may be warranted. Patients should be instructed before the procedure that the appearance of the affected nail will be permanently altered and that the recess created by the removal of the nail and granulation tissue will gradually resolve to a somewhat normal appearance."

The review authors have disclosed no relevant financial relationships.

Am Fam Physician. 2009;79:303-308.

Clinical Context

Pearls for Practice

• Although pain, edema, and erythema may be present in mild cases of ingrown toenails, the presence of seropurulent drainage should prompt consideration of surgical management.
• The current review recommends phenolization of the nail matrix to prevent a recurrent ingrown toenail. A tourniquet for the toe is recommended during the surgery for ingrown toenails, and patients may soak their toe 24 to 48 hours after the procedure. Systemic antibiotics are generally unnecessary when the ingrown toenail is removed surgically.

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