eMedicine Specialties > Dermatology > Nails

Paronychia

Steve Lee, MD, Physician in Plastic, Reconstructive, and Hand Surgery, Plastic Surgery, PLLC
Allison Vidimos, R PH, MD, Consulting Staff, Section of Micrographic Surgery (Mohs) and Oncology, Department of Dermatology, Cleveland Clinic Foundation; Yelena Bogdan, Stony Brook University Health Sciences Center School of Medicine (SUNY)

Updated: Aug 11, 2009

Introduction

Background

Paronychia is a soft tissue infection around a fingernail. Paronychia occurs in 2 forms: acute and chronic. The etiology, infectious agent, and treatment are usually different for each form, and the 2 forms are often considered separate entities.

Pathophysiology

Mechanism

Paronychia, whether acute or chronic, results from a breakdown of the protective barrier between the nail and the nail fold. The entry of organisms into the moist nail crevice results in the bacterial or fungal (yeast or mold) colonization of the area.

Depicted are the nail fold (A), dorsal roof (B), ventral floor (C), nail wall (D), perionychium (E), lunula (F), nail bed (G), germinal matrix (H), sterile matrix (I), nail plate (J), hyponychium (K), distal groove (L), fascial septa (M), fat pad (N), distal interphalangeal joint (O), and extensor tendon insertion (P).

Anatomy

The anatomy of the nail complex is shown in Media File 1. The nail is longitudinally flanked by 2 lateral folds or perionychium. Proximally, it is covered by the eponychium. Distal to the perionychium, the region immediately beneath the free edge of the nail is the hyponychium. The hyponychium serves as a tough physical barrier that resists bacterial infection.

The nail or nail plate lies immediately on top of the nail bed, which consists of 2 portions involved in the production, migration, and maintenance of the nail. The proximal portion, called the germinal matrix, contains active cells that are responsible for generating new nail. Damage to the germinal matrix results in malformed nails. The distal portion, the sterile matrix, adds thickness, bulk, and strength to the nail. The white crescent-shaped opacity at the proximal end of the nail is the lunula, which is the visible portion of the germinal matrix. The whiteness of the lunula is due to the poor vascularity of the germinal matrix. The nail arises from a mild proximal depression called the nail fold. The nail divides the nail fold into 2 components: the dorsal roof and the ventral floor, both of which contain germinal matrices. The skin overlying the nail fold is called the nail wall.

The nail bed receives its blood supply from the 2 terminal branches of the volar digital artery. A fine network in the proximal nail bed and in the skin proximal to the nail fold of the finger provides venous drainage. Lymphatic drainage follows a course similar to that of the venous network. The lymphatic network is dense in the nail bed, especially in the hyponychium. Innervation is derived from the trifurcation of the dorsal branch of the volar digital nerve. One branch goes to the nail fold, one to the pulp, and one to the distal tip of the finger.

Frequency

United States

Paronychia is the most commonly encountered hand infection, representing approximately 35% of all infections of the hand. Susceptible people include those whose occupations require them to have their hands in prolonged contact with water; such persons include bartenders, florists, bakers, and homemakers. In addition, individuals who are immunocompromised, such as those with HIV infection or those undergoing steroid therapy, are predisposed to paronychia.

Mortality/Morbidity

The motion of the affected finger may be limited in acute cases.

Race

No racial predilection is reported.

Sex

Paronychia is more common in women than in men, with a female-to-male ratio of 3:1.

Age

Paronychia may occur in patients of all ages.

Clinical

History

The patient's history is crucial in determining the possibility of more serious underlying systemic conditions that may predispose the patient to paronychia. These underlying conditions may include diabetes, obesity, hyperhidrosis, immunologic defects, polyendocrinopathy, and drug-induced immunosuppression.

• Acute paronychia
  • Patients with acute paronychia often present with a history of minor trauma to the fingertip or nail manipulation, intentional or not.
  • The presenting complaints are pain, tenderness, and swelling in one of the lateral folds of the nail.
• Chronic paronychia
  • Generally, patients complain of symptoms lasting 6 weeks or longer.
  • Inflammation, pain, and swelling may occur episodically, often after an exposure to water or a moist environment.

Physical

• Acute paronychia
  • The affected area often appears erythematous and swollen.
  • In more advanced cases, pus may collect under the skin of the lateral fold.
  • If untreated, the infection can extend into the eponychium, in which case, it is called eponychia.
  • Further extension of the infection can lead to the involvement of both lateral folds as it tracks under the nail sulcus; this progression is called a runaround infection.
  • In severe cases, the infection may track proximally under the skin of the finger and volarly to produce a concomitant felon. The fulminant purulence of the nail bed may generate enough pressure to lift the nail off the nail bed.
• Chronic paronychia
  • Swollen, erythematous, and tender nail folds without fluctuance are characteristic of chronic paronychia.
  • Eventually, the nail plates become thickened and discolored, with pronounced transverse ridges.
  • The cuticles and nail folds may separate from the nail plate, forming a space for the invasion of various microorganisms.

Causes

• Acute paronychia
  • Acute paronychia usually results from a traumatic event, however minor, that breaks down the physical barrier between the nail bed and the nail; this disruption allows the infiltration of infectious organisms.
  • Acute paronychia can result from seemingly innocuous conditions, such as hangnails, or from activities, such as nail biting, finger sucking, manicuring, or artificial nail placement.
  • Staphylococcus aureus is the most common infecting organism. Organisms, such as Streptococcus and Pseudomonas species, gram-negative bacteria, and anaerobic bacteria are other causative organisms.
  • Acute (and chronic) paronychia may also occur as a manifestation of other diseases, such as pemphigus vulgaris. Although instances of nail involvement in pemphigus vulgaris are rare, they can be severe, involving multiple digits and hemorrhage.
• Chronic paronychia
  • Chronic paronychia is primarily caused by the yeast fungus Candida albicans.
  • Other rare causes of chronic paronychia include bacterial, mycobacterial, or viral infection; metastatic cancer; subungual melanoma; and squamous cell carcinoma. Therefore, benign and malignant neoplasms should always be excluded when chronic paronychia does not respond to conventional treatment.
  • Chronic paronychia most often occurs in persons whose hands are repeatedly exposed to moist environments or in those who have prolonged and repeated contact with irritants such as mild acids, mild alkalis, or other chemicals. People who are most susceptible include housekeepers, dishwashers, bartenders, and swimmers.
• Other conditions associated with abnormalities of the nail fold that predispose individuals to chronic paronychia include psoriasis, mucocutaneous candidiasis, and drug toxicity from medications such as retinoids and protease inhibitors. Of particular interest is the antiretroviral drug indinavir, which induces retinoidlike effects and remains the most frequent cause of chronic paronychia in patients with HIV disease.

Differential Diagnoses

Other Problems to Be Considered

Herpetic whitlow is a viral infection of the pulp of the fingertip and the perionychium that can often be confused with the more common acute bacterial paronychia (see Herpetic Whitlow). Clear vesicles that are grouped on an erythematous base are characteristic of herpetic whitlow. Herpes simplex virus 1 causes approximately 60% of cases of herpetic whitlow, and herpes simplex virus 2 causes the remaining 40% of cases.

Malignancies, such as melanoma and squamous cell carcinoma, or lesions, such as chancres, granulomas, warts, or cysts, can occasionally mimic a paronychia.¹

Workup

Laboratory Studies

• Fluctuant paronychia is usually caused by bacteria; therefore, routine Gram staining helps in identifying the organism.
• Potassium hydroxide 5% smears may be helpful in diagnosing fluctuant paronychia if Gram staining results are negative or if candidal infection is suspected, as in chronic paronychia.
  • If Gram staining results are positive, the KOH preparation may demonstrate pseudomycelia and clusters of grapelike yeast cells.
  • KOH wet mounts from scrapings or discharge may show hyphae.
• Tzanck smears may be performed if herpetic whitlow is suspected.
  • Smears should be performed by using base scrapings of an unroofed vesicle.
  • The presence of multinucleated giant cells, often with visible viral inclusions, indicates a positive result.

Imaging Studies

• No radiologic studies are required.
• The diagnosis is primarily based on the features of the history and on the physical examination findings.

Treatment

Medical Care

The treatment of choice depends on the extent of the infection. If diagnosed early, acute paronychia without obvious abscess can be treated nonsurgically. If an abscess has developed, incision and drainage must be performed. Surgical debridement may be required if fulminant infection is present.

Herpetic whitlow and paronychia must be distinguished because the treatments are drastically different. Misdiagnosis and mistreatment may do more harm than good. Once herpetic whitlow is ruled out, one must determine whether the paronychia is acute or chronic and then treat it accordingly.²

• Acute paronychia
  • Warm water soaks of the affected finger 3-4 times per day until symptoms resolve are helpful.
  • Oral antibiotics with gram-positive coverage against S aureus, such as amoxicillin and clavulanic acid (Augmentin) or clindamycin (Cleocin), are usually administered concomitantly with warm water soaks.
  • Cleocin and Augmentin also have anaerobic activity; therefore, they are useful in treating patients with paronychia due to oral anaerobes contracted through nail biting or finger sucking.
  • Cleocin should be used instead of Augmentin in patients who are allergic to penicillin.
  • If the paronychia does not resolve or if it progresses to an abscess, it should be drained promptly.
• Chronic paronychia
  • The initial treatment of chronic paronychia consists of the avoidance of inciting factors such as exposure to moist environments or skin irritants. Keeping the affected lesion dry is essential for proper recovery. Choice of footgear may also be considered.
  • Any manipulation of the nail, such as manicuring, finger sucking, or attempting to incise and drain the lesion, should be avoided; these manipulations may lead to secondary bacterial infections.
  • Mild cases of chronic paronychia may be treated with warm soaks.
  • The initial medical treatment consists of the application of topical antifungal agents. Topical miconazole may be used as the initial agent. Oral ketoconazole or fluconazole may be added in more severe cases.
  • Patients with diabetes and those who are immunocompromised need more aggressive treatment because the response to therapy is slower in these patients than in others.
  • In cases induced by retinoids or protease inhibitors, the paronychia usually resolves if the medication is discontinued.

Surgical Care

If paronychia does not resolve despite best medical efforts, surgical intervention may be indicated. Also, if an abscess has developed, incision and drainage must be performed. Surgical debridement may be required if fulminant infection is present.

• Acute paronychia
  • No-incision technique
    • Less advanced paronychial abscesses can be drained simply by gently elevating the eponychial fold from the nail by using a small blunt instrument such as a metal probe or an elevator (see Media Files 2-3). This separation is performed at the junction of the perionychium and the eponychium and extends proximally enough to permit visualization of the proximal nail edge. Then, the proximal third of the nail can be excised with scissors and the pus evacuated.

Typical appearance of paronychia.

Simple acute paronychia can be drained by elevating the eponychial fold from the nail with a small blunt instrument such as a metal probe or elevator.

• This technique does not require an incision into the matrix. Often, no excision of any tissues is made because only blunt dissection and separation are needed to evacuate the pus from the paronychia.
• The wound should be well irrigated with isotonic sodium chloride solution, and plain gauze packing should be inserted under the fold to keep the cavity open and allow drainage.
• The patient should receive oral antibiotics for 5-7 days.
• The packing is removed after 2 days, and warm sodium chloride solution soaks are begun.
• Single- and double-incision techniques
  • If the paronychia is more advanced, it may need to be incised and drained.
  • A digital anesthetic block is usually necessary. If an anesthetic agent is used, it should consist of 1% lidocaine (Xylocaine) with no epinephrine for a ring block. The local injection of the anesthetic agent into the paronychia or the wound is often inadequate and more painful than the administration of drugs of a digital ring block.
  • If the paronychia involves only 1 lateral fold of the finger, a single longitudinal incision should be placed with either a number-11 or a number-15 blade directed away from the nail fold to prevent proximal injury with a subsequent nail growth abnormality. If both lateral folds of the finger are involved, incisions may be made on both sides of the nail, extending proximally to the base of the nail.
  • After the single or double incision is made, the entire eponychial fold is elevated to expose the base of the nail and drain the pus.
  • The proximal third of the nail is removed by using the technique described for the no-incision technique.
  • After the abscess is drained, the pocket should be well irrigated with isotonic sodium chloride solution, packed with plain packing, and dressed.
  • The patient should receive oral antibiotics for 5-7 days.
  • The dressing and packing are removed in approximately 2 days, and the affected finger is treated with warm soaks for 10-15 minutes 3-4 times per day.
• Chronic paronychia
  • The most common surgical technique used to treat chronic paronychia is called eponychial marsupialization.
  • In this technique, the affected digit is first anesthetized with 1% lidocaine (Xylocaine) with no epinephrine by using the digital ring block method.
  • Tourniquet control of the proximal digit is accomplished by using a finger of a latex glove with the distal end cut off.
  • With a No. 15 blade, a crescent-shaped incision is made proximal to the distal edge of the eponychial fold.
  • The distal incision is made approximately 1 mm proximal to the distal edge of the eponychium and along its curve.
  • At its widest end, the proximal incision is approximately 5 mm from the distal incision.
  • The incision should appear symmetric and extend to the edge of the nail fold on each side.
  • All affected tissue within the boundaries of the crescent and extending down to, but not including, the germinal matrix is excised. In effect, this procedure exteriorizes the infected and obstructed nail matrix and allows its drainage.
  • If the nail plate is grossly deformed at the time of surgery, it may be removed.
  • The excised region is packed with plain gauze wick, which is changed every 2-3 days.
  • Epithelialization of the excised defect occurs over the next 2-3 weeks.
  • Nail improvement occurs over the next 6-9 months but may require as long as 12 months to become apparent.

Diet

No change in diet is required.

Activity

Patients with either acute or chronic paronychia should keep affected areas clean and dry, and they should avoid any further trauma or manipulation of the nail.

Medication

The goals of pharmacotherapy are to eradicate the infection, reduce morbidity, and prevent complications.

Antibiotics

Therapy must cover all likely pathogens in the context of this clinical setting.

Clindamycin (Cleocin)

Lincosamide for treatment of serious skin and soft tissue staphylococcal infections. Also effective against aerobic and anaerobic streptococci (except enterococci). Inhibits bacterial growth, possibly by blocking dissociation of peptidyl t-RNA from ribosomes, causing RNA-dependent protein synthesis to arrest.

Dosing

Adult

150-450 mg/dose PO q6-8h; not to exceed 1.8 g/d
600-1200 mg/d IV/IM divided q6-8h depending on degree of infection

Pediatric

8-20 mg/kg/d PO as hydrochloride or 8-25 mg/kg/d as palmitate divided tid/qid
20-40 mg/kg/d IV/IM divided tid/qid

Interactions

Increases duration of neuromuscular blockade induced by tubocurarine and pancuronium; erythromycin may antagonize effects; antidiarrheals may delay absorption

Contraindications

Documented hypersensitivity; regional enteritis; ulcerative colitis; hepatic impairment; antibiotic-associated colitis

Precautions

Pregnancy

B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals

Precautions

Adjust dose in severe hepatic dysfunction; no adjustment necessary in renal insufficiency; associated with severe and possibly fatal colitis (allows overgrowth of Clostridium difficile)

Amoxicillin and clavulanic acid (Augmentin)

Drug combination used against bacteria resistant to beta-lactam antibiotics. In children > 3 mo, base dosing protocol on amoxicillin content. Because of different amoxicillin/clavulanic acid ratios in 250-mg tab (250/125) vs 250-mg chewable tab (250/62.5), do not use 250-mg tab until child weighs >40 kg.

Dosing

Adult

500-875 mg PO q12h or 250-500 mg PO q8h

Pediatric

<40 kg: 20-40 mg/kg/d PO divided bid
>40 kg: Administer as in adults

Interactions

Coadministration with warfarin or heparin increases risk of bleeding

Contraindications

Documented hypersensitivity; concomitant use of disulfiram

Precautions

Pregnancy

B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals

Precautions

Give for a minimum of 10 d to eliminate organism and prevent sequelae (eg, endocarditis, rheumatic fever); after treatment, perform cultures to confirm eradication of streptococci

Antifungals

Mechanism of action usually involves inhibiting pathways (enzymes, substrates, transport) necessary for sterol/cell membrane synthesis or altering the permeability of the cell membrane (polyenes) of the fungal cell.

Miconazole (Maximum strength Desenex)

Damages fungal cell wall membrane by inhibiting biosynthesis of ergosterol. Increases membrane permeability, causing nutrients to leak out and resulting in fungal cell death. Lotion preferred in intertriginous areas. If cream used, apply sparingly to avoid maceration effects.

Dosing

Adult

Cream and lotion: Cover affected areas bid for 2-6 wk
Powder: Liberally spray or sprinkle over affected area bid

Pediatric

Administer as in adults

Interactions

None reported

Contraindications

Documented hypersensitivity

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

If sensitivity or chemical irritation occurs, discontinue use; use only externally; avoid contact with eyes

Ketoconazole (Nizoral)

Fungistatic activity. Imidazole broad-spectrum antifungal agent; inhibits synthesis of ergosterol, causing cellular components to leak and resulting in fungal cell death.

Dosing

Adult

200 mg PO qd; increase to 400 mg PO qd if clinically indicated

Pediatric

<2 years: Not established
>2 years: 3.3-6.6 mg/kg/d PO once

Interactions

Isoniazid may decrease bioavailability; coadministration decreases rifampin and ketoconazole effects; may increase effect of anticoagulants; may increase toxicity of corticosteroids and cyclosporine (cyclosporine dose can be adjusted); may decrease theophylline levels

Contraindications

Documented hypersensitivity; fungal meningitis

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Hepatotoxicity may occur; may reversibly decrease corticosteroid serum levels (adverse effects avoided with dose of 200-400 mg/d); administer antacid, anticholinergics, or H2 blockers at least 2 h after administration

Follow-up

Further Outpatient Care

Patients with recurring or chronic paronychia require frequent follow-up monitoring to prevent possible superinfections or deep-seated infections.

Complications

Paronychia can result in more serious infections, such as felon, septic tenosynovitis, or osteomyelitis. Such infections occur more readily in patients who are immunosuppressed or whose condition has been mistreated or neglected.

Patient Education

• Instruct individuals to avoid any trauma to the fingernails and to avoid nail biting and finger sucking.
• Educate patients who work with their hands in a moist environment that such exposure predisposes them to infections.
• Inform patients that treatment is unlikely to be successful if their exposure to moist or wet environment is not changed.
• Instruct patients who are immunocompromised to remain vigilant against any minor trauma to the fingertips and nails.
• For excellent patient education resources, visit eMedicine's Skin, Hair, and Nails Center and Psoriasis Center. Also, see eMedicine's patient education article Nail Psoriasis.

Miscellaneous

Medicolegal Pitfalls

• Failure to distinguish between acute and chronic paronychia
• Failure to prescribe the correct or adequate treatment
• Failure to correctly differentiate paronychia from herpetic whitlow
• Failure to provide follow-up care

Multimedia

Media file 1: Depicted are the nail fold (A), dorsal roof (B), ventral floor (C), nail wall (D), perionychium (E), lunula (F), nail bed (G), germinal matrix (H), sterile matrix (I), nail plate (J), hyponychium (K), distal groove (L), fascial septa (M), fat pad (N), distal interphalangeal joint (O), and extensor tendon insertion (P).

Media file 2: Typical appearance of paronychia.

Media file 3: Simple acute paronychia can be drained by elevating the eponychial fold from the nail with a small blunt instrument such as a metal probe or elevator.

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Keywords

paronychia, eponychia, felon, finger infection, hand infection, runaround abscess, fingernail infection, runaround infection, acute paronychia, chronic paronychia, nail fold, nail wall, eponychium, lunula, nail bed, nail plate, hyponychium, Staphylococcus aureus, S aureus, Candida albicans, C albicans, eponychial marsupialization, herpetic whitlow, perionychium, perionychia, eponychia, eponychium

Contributor Information and Disclosures

Author

Steve Lee, MD, Physician in Plastic, Reconstructive, and Hand Surgery, Plastic Surgery, PLLC
Steve Lee, MD is a member of the following medical societies: American College of Surgeons and American Society of Plastic Surgeons
Disclosure: Nothing to disclose.

Coauthor(s)

Allison Vidimos, R PH, MD, Consulting Staff, Section of Micrographic Surgery (Mohs) and Oncology, Department of Dermatology, Cleveland Clinic Foundation
Allison Vidimos, R PH, MD is a member of the following medical societies: American Academy of Dermatology, American College of Mohs Micrographic Surgery and Cutaneous Oncology, American Medical Association, American Society for Dermatologic Surgery, American Society for Laser Medicine and Surgery, and International Society for Dermatologic Surgery
Disclosure: Nothing to disclose.

Yelena Bogdan, Stony Brook University Health Sciences Center School of Medicine (SUNY)
Yelena Bogdan is a member of the following medical societies: Phi Beta Kappa
Disclosure: Nothing to disclose.

Medical Editor

Richard K Scher, MD, Professor of Dermatology, University of North Carolina
Richard K Scher, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American College of Cryosurgery, American College of Physicians, American Dermatological Association, American Geriatrics Society, American Medical Association, Association of Military Surgeons of the US, International Society for Dermatologic Surgery, New York Academy of Sciences, Noah Worcester Dermatological Society, Rhode Island Medical Society, and Society for Investigative Dermatology
Disclosure: Nothing to disclose.

Pharmacy Editor

David F Butler, MD, Professor of Dermatology, Texas A&M University College of Medicine; Chair, Department of Dermatology, Director, Dermatology Residency Training Program, Scott and White Clinic, Northside Clinic
David F Butler, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American Medical Association, American Society for Dermatologic Surgery, American Society for MOHS Surgery, Association of Military Dermatologists, and Phi Beta Kappa
Disclosure: Nothing to disclose.

Managing Editor

Julia R Nunley, MD, Professor, Program Director, Dermatology Residency, Department of Dermatology, Virginia Commonwealth University Medical Center
Julia R Nunley, MD is a member of the following medical societies: American Academy of Dermatology, American College of Physicians, American Society of Nephrology, International Society of Nephrology, Medical Dermatology Society, Medical Society of Virginia, National Kidney Foundation, Phi Beta Kappa, and Women's Dermatologic Society
Disclosure: Johnson and Johnson stock holder dividends; Amgen stock holder dividends; Forest Lab, Inc stock holder dividends; Galaxo Smith Klein stock holder dividends; Covidien stock holder dividends; Novartis Grant/research funds Consulting; Biolex  sub-investigator

CME Editor

Glen H Crawford, MD, Assistant Clinical Professor, Department of Dermatology, University of Pennsylvania School of Medicine; Chief, Division of Dermatology, The Pennsylvania Hospital
Glen H Crawford, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Dermatology, American Medical Association, Phi Beta Kappa, and Society of USAF Flight Surgeons
Disclosure: Nothing to disclose.

Chief Editor

Dirk M Elston, MD, Director, Department of Dermatology, Geisinger Medical Center
Dirk M Elston, MD is a member of the following medical societies: American Academy of Dermatology
Disclosure: Nothing to disclose.

 The authors and editors of eMedicine gratefully acknowledge the contributions of previous author Mark F Hendrickson, MD, to the development and writing of this article.

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