Ingrown Nails 

Updated: Apr 22, 2019
Author: Amira M Elbendary, MBBCh, MSc; Chief Editor: William D James, MD 

Overview

Background

Ingrown toenail (onychocryptosis) is a fairly frequent problem resulting from either growth of nail fold inwards into the nail bed or abnormal embedding of the nail plate into the nail groove, causing significant discomfort. Although often thought to be synonymous, the terms ingrown nail and paronychia refer to different conditions. Both can cause significant discomfort. Ingrown toenails may cause pain with ambulation. See the image below.

Right great toe paronychia in a 3-year-old child. Right great toe paronychia in a 3-year-old child. Courtesy of Ann G. Egland, MD.

Retronychia is a rare variant of ingrown nail in which the nail plate is embedded into the proximal nail fold with subsequent inflammation of the proximal nail fold.[1]

Pathophysiology

Ingrown nails result from an alteration in the proper fit of the nail plate in the usual nail groove. Sharp spicules of the lateral nail margin develop and are gradually driven into the dermis of the nail groove. The nail acts as a foreign body. An inflammatory response occurs in the area of penetration, leading to erythema, edema, purulence, and development of granulation tissue.

The normal distance between the nail groove and the border of the nail is 1 mm. A thin epithelial layer covers the nail groove and protects it from irritation. With an increase in pressure on the nail bed and nail groove, an epidermal breakage occurs, with subsequent inflammation, pain, and infection.[2]

Ingrown nails generally occur as the result of poorly fitted footgear. However, this may be caused by prior trauma to or abnormal shape of the nail margin.[3]

Types of ingrown nail include the following[4] :

  • Neonatal: Occurs as a result of delayed overgrowth of the free nail margin on the tip of the toe and can be managed conservatively (see the first image below)

  • Infantile: Congenital form results from malalignment of the big toenail or as a result of hypertrophy of lateral nail fold

  • Adolescent : Most common cause is a narrow nail bed, resulting in ingrowing distal lateral nail

  • Adult: Most common cause is pressure that causes sharply bent lateral margin of the nail plate

  • Distal embedding from a big toe nail that is too short

  • Retronychia

  • Pincer nail (see second image below)

    Neonatal ingrown nail. Courtesy of Dermatology Res Neonatal ingrown nail. Courtesy of Dermatology Research and Practice (Haneke, E. "Controversies in the Treatment of Ingrown Nails." Dermatology Research and Practice. 2012; 2012:783924).
    Pincer nail. Courtesy of Dermatology Research and Pincer nail. Courtesy of Dermatology Research and Practice (Haneke, E. "Controversies in the Treatment of Ingrown Nails." Dermatology Research and Practice. 2012; 2012:783924).

Etiology

The following factors are implicated in the development of ingrown nails:

  • Trimming toenails improperly: Cutting the toenail rounded, V shape or too short will cause bulging of the soft tissue and the possibility to leave a nail spur that is difficult to remove, resulting in an inflammatory reaction with pressure necrosis. The proper way to trim the toenail is to cut it straight across beyond the nail bed.[5]

  • Poorly fitting shoes: The nail plate can be forced out of the nail groove by footwear that has a toe box that is too small for the forefoot. The constant pressure on the nail bed and nail groove results in breakage that starts an inflammatory process and eventually results in an ingrown nail.

  • Nail plate abnormality: Increased curvature of the nail plate, as in pincer nail, may develop into an ingrown nail.[5] Deformities that result from prior trauma or underlying bone pathology may predispose to ingrown nails.

  • Excessive sweating: It was noted that ingrown nails are common among teenagers and soldiers, in whom excessive sweating is present, which results in softening of the nail fold. With the participation in sports, nail spicules may develop and can easily pierce the adjacent softened nail fold.

  • Obesity causing deepening of the nail groove

  • Drugs (eg, antiviral therapy for HIV disease): Indinavir has been reported to have an association with an increased incidence of ingrown nails.[6] Cyclosporine, docetaxel, oral antifungals, and retinoids can cause excess nail fold granulation tissue and eventual ingrown nail development.[7, 8, 9]

  • Generalized joint hypermobility: Joint hypermobility through changes in foot biomechanics and gate affection increases medial midfoot pressure and loading during walking, and, as the first metatarsophalangeal joint bears the highest pressure, an ingrown toenail in the big toe may develop.[10]

  • Onychomycosis: This infection may result in brittle nails, which may form nail spicules and pierce the adjacent nail fold.

  • Heredity: Some people are genetically predisposed to inwardly curved nails, with distortion of one or both nail margins.

  • Pathological hallux interphalangeal angle (≥14.5): This was correlated with the development of ingrown hallux nail and may act as a predisposing factor.[11]

  • Paronychia with sporangium formation: This was reported to cause an ingrown nail.[12]

  • Hematopoietic stem cell transplantation: Children with hematopoietic stem cell transplantation have a higher incidence of ingrown nails and were found to have the aggressive forms, with more than 50% of patients having nail edge and bilateral great toe involvement, as well as recurrence in 37.5%.[13]

  • Nail consistency: Young male runners who have a hard nail consistency were found to have a higher incidence of ingrown nail.[14]

  • Diabetes: The prevalence of ingrown nails was found to be higher in diabetic patients, suggesting the role of diabetic vasculopathy in the development and evolution of ingrown nails.[15]

Epidemiology

Frequency

United States

Of all nail problems, this is the most common. Toenails are affected much more commonly than fingernails. The lateral margins of the great toe are most frequently affected.

International

In the United Kingdom, 10,000 cases per year have been reported.

In a Korean epidemiological study, a 10-year overall incidence was found to be 307.5 cases per 100,000 persons, with an increasing trend.[16]

Race

No racial predilection is noted.

Sex

Ingrown nail has a reported male-to-female ratio of 3:1. In reported cases of retronychia, a female predominance has been noted.[1]  A 2018 epidemiologic study revealed increased incidence and a higher prevalence in females.[16]

Age

The condition is observed in people of all ages but is most common in the second decade of life. Ingrown nails become much more common as children begin bearing weight on their feet and wearing shoes, although congenital onychocryptosis has been described,[17, 18] as have cases in infants.[19]

Prognosis

Prognosis is excellent. Complete healing is expected. In general, mortality is not associated with ingrown nails. Morbidity is chiefly the result of infection of the tissues. If neglected, abscess formation (paronychia) may occur or spread and lead to osteomyelitis, systemic infection, sepsis, or amputation.

Patient Education

For patient education resources, see the Foot Care Center and Skin, Hair, and Nails Center, as well as Ingrown Toenails and Paronychia.

Another good patient reference is www.familydoctor.org from the American Academy of Family Physicians.

 

Presentation

History

Patients present for care of ingrown nails due to discomfort. Ingrown nails may cause significant pain. If a toenail is involved, the discomfort worsens with weightbearing and ambulation. The patient with an ingrown nail presents with a sharp, focal pain adjacent to the nail bed of the affected digit. The patient or parents may typically describe crusting, purulence, and friable granulation tissue at the site.

Physical Examination

Upon examination, the following may be present:

  • Edema or inflammation of tissue surrounding the nail bed

  • Erythema of the same tissue

  • Macerated or friable granulation tissue

  • Crusting

  • Drainage

  • Hypertrophy of the nail margin

  • Hypertrophy of the surrounding epidermis

Accordingly, ingrown nail has been divided into the following three stages[20] :

  • Stage 1: Mild erythema edema and pain with pressure

  • Stage 2: Significant erythema, edema, local infection, and discharge

  • Stage 3: Granulation tissue formation and hypertrophy of the lateral wall besides the significant erythema, edema, and discharge (see image below)

    Stage 3 ingrown nail. Courtesy of Wikimedia Common Stage 3 ingrown nail. Courtesy of Wikimedia Commons.

Complications

Development of paronychia is the most common complication. If paronychia is not treated, the condition may progress to cellulitis, osteomyelitis, or systemic infection.

If neglected, abscess formation (paronychia) can spread and lead to osteomyelitis, systemic infection, and sepsis; amputation of the digit may even be required for definitive treatment.

An ingrown nail causes varying degrees of inflammation in the surrounding tissue, and this may predispose to infection if not well treated.

Hypertrophy of the medial and lateral skin folds may occur, as shown in the image below, and bilateral sidewall hypertrophy that covers the entire nail has been reported.[21]

Hypertrophy of the lateral nail fold that partiall Hypertrophy of the lateral nail fold that partially cover the nail. Courtesy of Dermatology Research and Practice (Haneke, E. "Controversies in the Treatment of Ingrown Nails." Dermatology Research and Practice. 2012; 2012:783924).

Pyogenic granuloma may develop on longstanding infected ingrown nails.

If left untreated, chronic inflammation may cause skin bridging secondary to epithelialization of the adjacent inflamed hypertrophied soft tissue.[22]

Keloid formation may result from chronic inflammation, especially in cases of recurrent ingrown nails.[23]

Recurrence is defined as the occurrence of pain, discomfort, erythema, and/or drainage at the site of the treated nail edge.

Although infrequent, postsurgical infection may occur in a small percentage of patients. Appropriate precautions should be given to return for any signs of infection or fever.

 

DDx

 

Workup

Laboratory Studies

Usually, no laboratory studies are required in patients with ingrown nails. Potassium chloride (KOH) and fungal culture may be considered, if indicated by physical examination findings suspicious for a fungal etiology.

Imaging Studies

Radiography may be appropriate to rule out fracture, foreign body, or suspected osteomyelitis as indicated by history and physical examination.

 

Treatment

Medical Care

Conservative management is used in stage 1 ingrown nails, with the advantage of avoidance of minor surgical procedures with their associated pain and short-term disability.

General measures

Well-fitted shoes with a wide toe box or open toe are recommended.

Trim toenails properly, with avoidance of cutting back to the lateral margins in a curved pattern.

Manage underlying possible predisposing factors such as onychomycosis and hyperhidrosis.

Soak the affected toe in warm water, followed by application of topical antibiotics or silver nitrates in case there is granulation tissue.

Conservative methods

Cotton wick insertion in the lateral groove corner is one method. Using a nail elevator or small curette, small wisps of cotton are inserted under the lateral edge of the ingrown nail. Symptomatic improvement was reported in 79% of patients in a case series with mean follow up of 24 weeks.[24] See the image below.

Schematic view for cotton wick insertion. Courtesy Schematic view for cotton wick insertion. Courtesy of Dermatology Research and Practice (Haneke, E. "Controversies in the Treatment of Ingrown Nails." Dermatology Research and Practice. 2012; 2012:783924).

Toe taping is an alternative method. The affected toe is taped in a way that the one end of the tape is placed on the side of the ingrown nail along the granulation tissue and twisted around the toe at an angle, with the other end overlapping the first without covering the wound itself. This taping allows drainage of accumulated pus, drying of the wound, and decreasing the pressure on the nail bed.[25] See the image below.

Schematic view illustrating taping of the nail. Co Schematic view illustrating taping of the nail. Courtesy of Dermatology Research and Practice (Haneke, E. "Controversies in the Treatment of Ingrown Nails." Dermatology Research and Practice. 2012; 2012:783924).

Nail splinting by flexible tube (gutter treatment) involves a small sterilized vinyl intravenous drip infusion tube, which is cut and slit appropriately from top to bottom with one end cut diagonally for smooth insertion. The lateral edge of the affected nail plate is splinted with this tube under local anesthesia. The plastic tube is then covered by adhesive or wound closure strips and the patient is instructed to wash his or her toe daily with povidone iodine solution for 3-4 weeks. This method allows the nail spicule to grow without injuring the nail fold, and the inflammatory process will subside.[26] See the image below.

Schematic view illustrating gutter technique. Cour Schematic view illustrating gutter technique. Courtesy of Dermatology Research and Practice (Haneke, E. "Controversies in the Treatment of Ingrown Nails." Dermatology Research and Practice. 2012; 2012:783924).

The split tape-strap technique is a procedure that involves elastic tape cut into pieces about 3 cm wide and about 10 cm long, folded longitudinally in half. A slit is then created on the width of the ingrown nail along the short edge of one third of the tape length. The ingrown nail is then inserted in the slit, orienting the tape with the shorter side of the tape towards the dorsal side of the toe and hooking the slit edge of the longer side on the ingrown nail and attaching it to the plantar surface of the toe. This procedure showed favorable results as monotherapy or when combined with other conservative procedures.[27]

Other methods reported to be effective but on a smaller number of patients include angle correction technique,[28] dental floss technique,[29] nail wiring,[30] nail brace,[31] knot technique,[32] Nishioka procedure,[33] and use of an artificial acrylic nail.[34]

Surgical Care

Different surgical modalities have been described.[35]

Nonselective surgical management can include the following procedures:

  • Complete nail evulsion

  • Partial nail evulsion

  • Wedge matrix excision

  • Partial matrix excision

  • Total matrix excision

  • Vandenbos procedure[28]

These procedures were reported to have high recurrence rates. However, a retrospective study from 2017 to evaluate the Vandenbos procedure reported on 59 ingrown toenails and found that while 18% of patients had one or more minor complications with in the first 2 months of surgery, no recurrences were reported.[36]

Partial nail avulsion surgical techniques are as follows:

  • Phenol matricectomy: It is the most commonly used chemical agent for matricectomy, with good results and a low recurrence rate; however, because of the extensive tissue damage it causes, drainage and delayed wound healing may occur.[37] Dizziness, abdominal pain, hemoglobinuria, cyanosis, and cardiac arrhythmias are adverse effects that have been reported following phenol application.[38] Application of phenol for 1 minute duration has a better safety profile than prolonged application and is sufficient for destruction of the germinal matrix.[38]  Use of an antimicrobial hydrogel containing oakin, an oak extract, may help reduce phenol caustic activity and healing time.[39]

  • Chemical matricectomy with 10% sodium hydroxide: This is as effective as phenol. It acts through liquefactive necrosis by alkali burning, resulting in less postoperative drainage and a shorter healing time. However, care should be taken to not apply strong alkali for prolonged periods, as this may cause excessive tissue damage by from slowly progressive liquefactive necrosis.[40]  Additional adverse effects described following sodium hydroxide matricectomy include allodynia, nail dystrophy, and hyperalgesia.[41]

  • Trichloroacetic acid matricectomy: Chemical matricectomy using 90% trichloroacetic acid was tested following partial nail avulsion and was found to be helpful, with low rates of postoperative morbidity.[42] Trichloroacetic acid had shown high success rates with a healing time of less than two weeks.[43, 44]

  • Matricectomy using carbon dioxide laser: Performing selective matricectomy using a carbon dioxide laser is associated with a low recurrence rate, but technical difficulty, prolonged healing time, and poor cosmetic results are drawbacks for such a procedure.[45]

  • The Winograd procedure (wedge resection): This involves local anesthesia and digital tourniquet application followed by a longitudinal incision along the eponychium followed by removal of the lateral nail border, hypertrophied tissue, and germinal matrix.[46]

  • Wedge excision and phenol matricectomy

  • Cryotherapy

  • Electrocautery or curettage: Both methods are safe with high success rates. Curettage was found to be superior to electrocautery regarding postoperative inflammation and pain. Electrocauterization may cause heat osteonecrosis that may result in prolonged postoperative pain from the heat generated from the periosteum.[47]

In a study aiming to compare the wedge resection method and chemical matricectomy using sodium hydroxide, postoperative pain severity, drainage rate, and recovery time were reduced with chemical matricectomy.[48] However, there was no difference regarding recurrence rate.

Trichloroacetic acid was found to be as effective as phenol. It remains an option when phenol is not available.[49]

The use of local anesthetics that contain vasoconstrictors has shown to be effective, eliminating the adverse effects of using a digital tourniquet (lower anesthetic effect and postoperative bleeding). Reduction of postoperative bleeding and perioperative pain can be achieved with the addition of epinephrine to the local anesthetic, but use caution so as not to inject it into an artery.[50]

Postoperative care

The patient is allowed to walk after the operation.

Rest at home with feet elevation is recommended, with intake of analgesics when needed.

Normal ambulation and activity can be resumed as soon as 48 hours after the operation.

The patient is instructed to use antiseptic soaks with diluted povidone-iodine solution once a day for 15 minutes, followed by topical antibiotic cream and gauze.

Always keep the wound dry and clean.

Consultations

Consult a podiatrist, dermatologist, or orthopedic surgeon for routine follow-up care or for patients in whom primary avulsion therapy has been unsuccessful.

Close follow-up care with an orthopedist is required if inflammatory osteophytic changes are observed or if evidence of osteomyelitis is present. Immediate antibiotic treatment should begin, and inpatient treatment may be needed for osteomyelitis.

Follow-up with a primary care physician is indicated for any type of immunosuppression, including diabetes mellitus. Antibiotics may be started in those who are immunosuppressed.

Diet

No dietary limitations are required.

Activity

Rest, keep the extremity elevated, keep the site dry, and maintain limited weightbearing until healing has taken place.

Prevention

Good hygiene and wearing appropriately sized footgear are important. Shoes with narrow, pointed toes that compress the forefoot should not be worn.

Teaching the patient and parents to keep the nail margin in the nail groove, how to properly trim the nail, and how to choose shoes with an accommodating toe box is vital to prevent further visits.

Long-Term Monitoring

Provide appropriate follow-up care as indicated. Provide patients and parents with specific indications for return, such as development of infection, bleeding, or any worsening of the condition of the digit.

 

Medication

Medication Summary

Antibiotics are rarely indicated for ingrown nails. Patients may generally be treated as outpatients. Pain control should be provided.

Analgesic agents

Class Summary

Pain control is essential to quality patient care. Analgesics ensure patient comfort and have sedating properties, which are beneficial for patients who have sustained trauma or injuries.

Ibuprofen (Motrin, Advil)

Ibuprofen is a nonsteroidal anti-inflammatory for pain control and treatment of local inflammation.

Acetaminophen (FeverAll, Tylenol)

Acetaminophen is the drug of choice for pain in patients with documented hypersensitivity to aspirin or NSAIDs, with upper GI disease, or who are taking oral anticoagulants.

 

Questions & Answers

Overview

What are ingrown nails?

What is the pathophysiology of ingrown nails?

What are the types of ingrown nails?

What causes ingrown nails?

What is the prevalence of ingrown nails in the US?

What is the global prevalence of ingrown nails?

What are the racial predilections of ingrown nails?

What are the sexual predilections of ingrown nails?

Which age groups have the highest prevalence of ingrown nails?

What is the prognosis of ingrown nails?

Presentation

Which clinical history findings are characteristic of ingrown nails?

Which physical findings are characteristic of ingrown nails?

What are the stages of ingrown nails?

What are the possible complications of ingrown nails?

DDX

What are the differential diagnoses for Ingrown Nails?

Workup

What is the role of lab testing in the workup of ingrown nails?

What is the role of imaging studies in the workup of ingrown nails?

Treatment

How are ingrown nails treated?

What is included in the conservative treatment of ingrown nails?

Which surgical procedures are used in the treatment of ingrown nails?

What are the partial nail avulsion surgical techniques used in the treatment of ingrown nails?

What is included in postoperative care following surgery for ingrown nails?

Which specialist consultations are beneficial to patients with ingrown nails?

Which dietary modifications are used in the treatment of ingrown nails?

Which activity modifications are used in the treatment of ingrown nails?

How are ingrown nails prevented?

What is included in long-term monitoring following the treatment of ingrown nails?

Medications

Which medications are used in the treatment of ingrown nails?

Which medications in the drug class Analgesic agents are used in the treatment of Ingrown Nails?