What is paronychia?

What is Paronychia?

Paronychia is a painful inflammatory condition of the nail folds, characterized by erythema, swelling, and tenderness of the lateral or proximal nail folds, which can progress to abscess formation and may be classified as either acute or chronic based on duration. 1

Types and Clinical Presentation

Acute Paronychia

• Definition: Inflammation lasting less than 6 weeks
• Presentation:
  • Painful erythematous inflammation with swelling and tenderness of the lateral nail folds
  • May progress to abscess formation with discharge
  • Can develop friable granulation tissue mimicking ingrown nails 1
• Common locations: Thumbs and great toes are most frequently affected 1
• Causative factors:
  • Direct or indirect trauma to the cuticle or nail fold 2
  • Polymicrobial infections after protective nail barrier breach 3
  • Secondary bacterial/mycological superinfections (present in up to 25% of cases) 1

Chronic Paronychia

• Definition: Symptoms persisting for at least six weeks 3
• Presentation: Persistent inflammation of proximal nail fold
• Etiology: Represents an irritant dermatitis to the breached nail barrier 3
• Common irritants: Acids, alkalis, and chemicals used by:
  • Housekeepers
  • Dishwashers
  • Bartenders
  • Florists
  • Bakers
  • Swimmers 3

Pathogenesis

The development of paronychia involves:

1. Barrier disruption: Damage to the protective nail barrier
2. Inflammation: Initial inflammatory response to irritants or trauma
3. Infection: Secondary infection with bacteria or fungi
   • Both gram-positive and gram-negative organisms can be involved 1
   • Fungal infections (particularly Candida species) may be present

In cases related to anticancer agents (particularly EGFR inhibitors), paronychia results from:

• Inhibition of EGFR-dependent pathways in keratinocytes
• Altered differentiation and migration of epidermal cells
• Thinning of periungual stratum corneum
• Potential piercing of perionychium by the nail plate (onychocryptosis) 1

Management Approach

Prevention

Preventive measures should be systematically promoted:

• Gentle skin care
• Preventive correction of nail curvature (podiatrist referral if needed)
• Avoiding repeated friction, trauma, and excessive pressure
• Wearing gloves while cleaning
• Avoiding biting nails or cutting nails too short
• Using antimicrobial soaks and proper cleansers
• Regular trimming of nails (straight, not too short)
• Daily application of topical emollients to cuticles
• Wearing comfortable shoes and cotton socks 1

Treatment of Acute Paronychia

Grade 1 (Mild):

• Continue monitoring for changes in severity
• Topical povidone iodine 2%
• Topical antibiotics/corticosteroids
• Reassess after 2 weeks 1

Grade 2 (Moderate):

• Obtain bacterial/fungal cultures if infection is suspected
• Topical povidone iodine 2%
• Topical beta-blocking agents or antibiotics with corticosteroids
• Consider oral antibiotics
• Reassess after 2 weeks 1

Grade 3 (Severe) or Intolerable Grade 2:

• Interrupt any causative medications until resolution
• Obtain cultures
• Topical treatments as above
• Oral antibiotics
• Consider partial nail avulsion for severe cases
• Reassess after 2 weeks 1

Treatment of Chronic Paronychia

• Address underlying causes (eliminate exposure to irritants)
• Topical steroids are more effective than systemic antifungals 2
• Consider calcineurin inhibitors 3
• For recalcitrant cases, surgical options include:
  • En bloc excision of the proximal nail fold
  • Eponychial marsupialization with or without nail removal 2

Special Considerations

• Diagnosis confirmation: Treatment should not be instituted on clinical grounds alone; proper diagnosis is essential 1
• Secondary infections: Bacterial or mycological superinfections are present in up to 25% of cases 1
• Occupational disease: Often recurrent in certain professions with frequent water exposure 4
• Medication-induced: Particularly common with EGFR inhibitors used in cancer treatment 1

Common Pitfalls to Avoid

1. Treating without proper diagnosis: Always confirm diagnosis before initiating treatment
2. Ignoring underlying causes: Especially in chronic paronychia
3. Inadequate drainage: When abscess is present, proper drainage is essential
4. Overlooking patient education: Critical to reduce recurrence
5. Inappropriate antibiotic use: Oral antibiotics are usually not needed if adequate drainage is achieved in immunocompetent patients 3

Proper management of paronychia requires addressing both the inflammatory component and any secondary infection while restoring the protective nail barrier to prevent recurrence.