What are the treatment options for paronychia and nail fungal infections?

Treatment of Paronychia and Nail Fungal Infections

Paronychia Treatment

For paronychia, topical povidone iodine 2% combined with topical antibiotics and corticosteroids is first-line therapy, with drainage being the most critical intervention when an abscess is present. 1

Acute Paronychia Management Algorithm

Mild acute paronychia (no abscess):

• Apply topical povidone iodine 2% to the affected area daily 1
• Alternate with topical antibiotic and corticosteroid combinations 1
• Implement antiseptic soaks with dilute vinegar (1% acetic acid) for 10-15 minutes twice daily 1, 2
• Warm soaks with or without Burow solution are effective alternatives 2

Moderate acute paronychia (early abscess formation):

• Continue topical povidone iodine 2% 1
• Apply mid to high potency topical steroid ointment to nail folds twice daily 1
• Consider topical beta-blocking agents if granulation tissue develops 1

Severe acute paronychia (established abscess):

• Drainage is mandatory and the most important intervention 3, 1, 2
• Drainage options range from instrumentation with a hypodermic needle to wide incision with a scalpel, with an intra-sulcal approach preferable to nail fold incision 2, 4
• Obtain bacterial/viral/fungal cultures before initiating antimicrobial therapy 1
• Consider partial nail avulsion for severe cases 1
• Oral antibiotics are usually unnecessary if adequate drainage is achieved, unless the patient is immunocompromised or severe infection is present 2

Chronic Paronychia Management

Chronic paronychia (symptoms ≥6 weeks) represents an irritant contact dermatitis rather than infection:

• Identify and eliminate irritant exposures (acids, alkalis, chemicals used by housekeepers, dishwashers, bartenders, florists, bakers, swimmers) 2
• Apply topical steroids or calcineurin inhibitors to treat inflammation 2
• Consider combination therapy with insulating polymer (Syn-cell barrier), antifungals (octopirox and climbazole), and anti-inflammatory agents (corticoid-like repair) applied three times daily for 2 months 5

For Candida-associated chronic paronychia:

• Topical imidazole lotions are first-line treatment 3, 1
• Oral itraconazole 200 mg daily may be considered if nail plate invasion is present 1
• For severe candidiasis, add oral fluconazole 100 mg for 20 days 5

Prevention of Paronychia Recurrence

• Keep hands dry and avoid trauma to nails 1
• Wear protective gloves when exposed to irritants 1
• Trim nails straight across 1
• Apply emollients to periungual tissues regularly 1

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Nail Fungal Infection (Onychomycosis) Treatment

Terbinafine 250 mg daily is the best first-line treatment for dermatophyte onychomycosis, given for 6 weeks for fingernails and 12 weeks for toenails, achieving 70-80% cure rates for toenails and 80-90% for fingernails. 6, 7

Treatment Algorithm by Causative Organism

Dermatophyte onychomycosis (most common, primarily Trichophyton rubrum):

• First-line: Terbinafine 250 mg daily for 6 weeks (fingernails) or 12 weeks (toenails) 6, 7
• Second-line: Itraconazole with two dosing options 6:
  • Continuous therapy: 200 mg daily for 12 weeks
  • Pulse therapy: 400 mg daily for 1 week per month (clinical cure rates 14-26%, mycological cure 54%)

Candida onychomycosis:

• First-line: Itraconazole 200 mg daily or pulse therapy 400 mg daily for 1 week per month, repeated for 2-4 months 3, 6, 8
• Itraconazole demonstrates 92% cure rates for fungal nail infections 8
• Terbinafine has limited and unpredictable activity against Candida and should be avoided 3
• Fluconazole 200-400 mg daily is a reasonable alternative if itraconazole is contraindicated, though less effective 8

Non-dermatophyte mold (NDM) onychomycosis (emerging pathogens including Fusarium species, Onychocola canadensis):

• Treatment follows similar principles to dermatophyte infections, though these are increasingly detected 9

Topical Therapy for Onychomycosis

Topical agents are inferior to systemic therapy except for very distal infection or superficial white onychomycosis:

• Ciclopirox 8% lacquer applied daily for up to 48 weeks, indicated for mild to moderate onychomycosis without lunula involvement 6, 10
• Amorolfine 5% lacquer applied once or twice weekly for 6-12 months 6, 9
• Topical therapy should be used as an adjunct to systemic therapy for improved cure rates 6
• Concomitant use of ciclopirox 8% topical solution and systemic antifungals is not recommended 10

Critical Management Principles

Mycological confirmation before treatment:

• Obtain nail specimens for KOH preparation, fungal culture, or nail biopsy to confirm diagnosis before initiating therapy 6, 7
• Starting treatment without confirmation leads to unnecessary therapy for non-fungal nail dystrophies 6

Treatment duration and follow-up:

• Minimum follow-up period of 48 weeks from treatment start to allow identification of superior drug and detection of relapse 6
• Complete cure (clear nail and negative mycology) may take up to 48 weeks, with initial improvement possibly not visible until 6 months 10
• Inadequate treatment duration results in higher relapse rates (25% overall) 6

Monthly nail debridement:

• Removal of unattached, infected nail by a healthcare professional as frequently as monthly is essential when using topical therapy 10

Special Population Considerations

Diabetic patients:

• Terbinafine is preferred over itraconazole due to lower risk of drug interactions and no hypoglycemia risk 6
• Carefully consider the risk of nail removal procedures in patients with insulin-dependent diabetes or diabetic neuropathy 10

Pediatric patients:

• Both terbinafine and itraconazole are first-line options with higher cure rates than adults 6
• Use weight-based dosing for terbinafine and pulse therapy for itraconazole 6

Prevention of Onychomycosis Recurrence

• Apply regular antifungal powder inside shoes 6
• Periodically spray terbinafine solution into shoes 6

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Common Pitfalls to Avoid

For paronychia:

• Avoid prolonged use of topical steroids without addressing the underlying irritant cause 1
• Don't overlook potential secondary fungal infections in chronic paronychia 1
• Antibiotics are overused; they are indicated only when regional or systemic spread is present on the day following infection or during the next few days 11
• A paronychia that has been opened but not cured should be reoperated upon rapidly 11

For onychomycosis:

• Ignoring drug interactions, particularly itraconazole with statins, antiretrovirals, and in heart failure patients 6
• Using terbinafine for Candida onychomycosis (ineffective) 3
• Applying nail polish or other nail cosmetics on treated nails 10
• Using ciclopirox near heat or open flame (product is flammable) 10
• Expecting complete cure with topical therapy alone; less than 12% of patients achieve completely clear or almost clear toenails with ciclopirox 10