What is the appropriate management of acute and chronic paronychia, including indications for incision and drainage, antibiotic selection (with MRSA coverage), and topical antifungal therapy?

Management of Paronychia

For acute paronychia, start with warm water or dilute white vinegar soaks (1:1 dilution) 3-4 times daily for 15 minutes, combined with topical 2% povidone-iodine twice daily; reserve oral antibiotics for cases with systemic signs of infection or when adequate drainage cannot be achieved, using cephalexin or amoxicillin-clavulanate as first-line agents, with trimethoprim-sulfamethoxazole for MRSA coverage. 1, 2

Acute Paronychia Management

Initial Conservative Treatment (Mild Cases)

• Implement warm water soaks for 15 minutes 3-4 times daily OR white vinegar soaks (1:1 dilution with water) for 15 minutes daily as first-line therapy 1, 3
• Apply topical 2% povidone-iodine to the affected area twice daily for 10-15 minutes 1, 3, 2
• Use mid- to high-potency topical steroid ointment (not cream) to nail folds twice daily to reduce inflammation, applied immediately after soaking 1, 3
• Topical antibiotics may be added when simple soaks do not relieve inflammation 4

Indications for Incision and Drainage

• Any abscess formation mandates drainage regardless of size 1, 4
• Drainage options range from instrumentation with a hypodermic needle to wide incision with scalpel 1, 4
• For severe cases with pyogenic granuloma, partial nail plate avulsion may be necessary 1
• An intra-sulcal approach is preferable to a nail fold incision when draining abscesses 5

Antibiotic Selection

When to Use Oral Antibiotics:

• Oral antibiotics are usually NOT needed if adequate drainage is achieved, unless the patient is immunocompromised or severe infection is present 1, 4
• Start oral antibiotics if signs of systemic infection are present (fever >38°C, tachycardia, elevated WBC) 1

First-Line Antibiotic Choices:

• Cephalexin OR amoxicillin-clavulanate (Augmentin 500/125 mg every 12 hours) for standard acute paronychia 1, 2
• These agents provide coverage for methicillin-susceptible Staphylococcus aureus and streptococci 6

MRSA Coverage:

• If initial treatment with cephalexin fails, use trimethoprim-sulfamethoxazole (Bactrim) as it provides broader coverage including MRSA 1
• Alternative MRSA-active agents include doxycycline or clindamycin for susceptible isolates 6
• Avoid clindamycin as first-line due to inadequate coverage for some streptococcal species and increasing resistance patterns 1, 2

Critical Microbiological Considerations

• Up to 25% of paronychia cases have secondary bacterial or fungal superinfections 1, 2, 7
• Obtain bacterial cultures before starting antibiotics, especially in severe cases or treatment failures 1, 2
• Swab any purulent drainage for culture and prescribe antibiotics based on results 1

Common Pitfalls to Avoid

• Stop topical steroids immediately if purulent drainage develops, as steroids can worsen infection 3
• Do not use trimethoprim-sulfamethoxazole as monotherapy for cellulitis due to possible group A Streptococcus involvement 6
• Systemic antibiotics are ineffective for ingrown nail-associated paronychia unless infection is proven 7

Chronic Paronychia Management

Pathophysiology and Approach

• Chronic paronychia (≥6 weeks duration) represents an irritant contact dermatitis to the breached nail barrier, not primarily an infection 4, 5
• Common irritants include acids, alkalis, and chemicals used by housekeepers, dishwashers, bartenders, florists, and swimmers 4

Treatment Strategy

• Treatment is aimed at stopping the source of irritation while treating inflammation with topical steroids or calcineurin inhibitors 4
• Keep the infected area dry, as moisture is a major contributing factor 1
• For candidal paronychia, drainage is the most important intervention, followed by topical azoles or polyenes 1
• Treatment may take weeks to months to achieve resolution 4

Topical Antifungal Therapy

• Topical azoles (e.g., clotrimazole, ketoconazole) and polyenes are effective for candidal skin infections 1
• Topical imidazoles, ciclopirox, and amorolfine can be used in combination with systemic antifungals when onychomycosis is present 6
• Secondary fungal colonization is common in chronically irritated tissue 5

Follow-Up and Escalation

• Reassess after 2 weeks of treatment 1, 3, 2
• If no improvement is seen, escalate therapy or consider referral to dermatology or podiatry 1, 3, 2
• For refractory cases with pyogenic granuloma, topical timolol 0.5% gel twice daily under occlusion for 1 month has shown complete clearance 1
• Silver nitrate chemical cauterization or cryotherapy are alternative options for persistent lesions 1

Prevention Education

Critical preventive measures to discuss:

• Avoid biting nails or cutting nails too short; trim nails straight across and not too short 1, 3
• Apply topical emollients daily to cuticles and periungual tissues to maintain skin barrier function 1, 3
• Wear gloves while cleaning and during exposure to irritants 1
• Wear comfortable, well-fitting shoes and cotton socks to avoid repeated trauma 1, 3