How should acute and chronic paronychia be treated in an otherwise healthy adult, and what adjustments are needed for immunocompromised patients, methicillin‑resistant Staphylococcus aureus (MRSA) risk, or penicillin allergy?

Treatment of Paronychia

For acute paronychia with signs of infection (warmth, purulence, spreading erythema), start cephalexin as first-line oral antibiotic after ensuring adequate drainage; for chronic paronychia, use high-potency topical corticosteroids and keep the area dry, as this is primarily an irritant contact dermatitis, not an infection. 1

Acute Paronychia Management

Initial Conservative Measures

• Warm water or dilute vinegar soaks (1:1 white vinegar to water) for 15 minutes, 3–4 times daily to reduce inflammation and promote drainage 1
• Topical povidone-iodine 2% applied twice daily to the periungual area 1
• Mid- to high-potency topical corticosteroid ointment to nail folds twice daily to reduce inflammatory edema 1

When to Use Oral Antibiotics

Initiate systemic antibiotics only when clinical signs of infection are present: increased warmth, purulence, spreading erythema beyond the nail fold, or systemic symptoms (fever, lymphangitis) 1

Important caveat: Surgical drainage alone cures 98% of uncomplicated acute paronychia in healthy adults without antibiotics 2. Reserve antibiotics for severe infection, immunocompromised patients, or when adequate drainage cannot be achieved.

Antibiotic Selection Algorithm

First-line agent:

• Cephalexin 500 mg four times daily for 7–10 days – preferred initial choice for methicillin-susceptible Staphylococcus aureus and streptococci 1, 2

If cephalexin fails or worsens after 2 weeks:

• Switch to trimethoprim-sulfamethoxazole (Bactrim) 1–2 double-strength tablets twice daily for broader coverage including MRSA 1, 3
• Obtain bacterial and fungal cultures before switching to guide therapy 1, 3

Second-line alternatives:

• Amoxicillin-clavulanate 875/125 mg twice daily for broader coverage including anaerobes 1, 2

For penicillin allergy:

• Clindamycin 300–450 mg three times daily (covers staphylococci, streptococci, and anaerobes) 2
• Doxycycline 100 mg twice daily as alternative 2

Critical pitfall: Avoid clindamycin as monotherapy for acute paronychia—it lacks adequate streptococcal coverage and resistance rates are rising 1

For suspected or confirmed MRSA:

• Trimethoprim-sulfamethoxazole is bactericidal against MRSA and preferred 2, 3
• Clindamycin is alternative but check for inducible resistance in erythromycin-resistant strains 2

Surgical Intervention

• Incision and drainage is mandatory for any abscess formation, regardless of other treatments 1
• Drainage alone achieves 98% cure rate without antibiotics in healthy adults 2
• Culture purulent material to guide antimicrobial therapy 1

Secondary Candida Superinfection

Up to 25% of acute paronychia cases develop secondary Candida infection 2, 3

Treatment approach:

• First-line: Topical imidazole lotions (clotrimazole or miconazole) 2
• For nail plate invasion or severe cases: Oral itraconazole 200 mg daily for minimum 4 weeks (fingernails) or 12 weeks (toenails) 2
• Avoid terbinafine for Candida—it has limited and unpredictable activity against Candida species 2

Chronic Paronychia Management

Understanding the Pathophysiology

Chronic paronychia is primarily an irritant contact dermatitis caused by disruption of the cuticle barrier, NOT a primary infection 1. Bacterial and yeast organisms are secondary colonizers rather than primary pathogens 1.

At-Risk Populations

Frequently seen in individuals with wet occupations (housekeeping, dishwashing, bartending, floristry, baking, swimming) and children who suck their thumbs 1

Core Treatment Strategy

Most important intervention: Keep the affected area dry 1

Topical therapy:

• High-potency topical corticosteroids (alone or combined with topical antibiotic) are the mainstay of treatment 1
• Apply emollients regularly to cuticles and periungual skin to restore barrier function 1

Avoid systemic antibiotics unless secondary bacterial infection is confirmed—chronic paronychia is not primarily infectious 1

Special Considerations for Immunocompromised Patients

For immunocompromised hosts (diabetes, immunosuppression, prosthetic heart valves):

• Lower threshold for oral antibiotics even with adequate drainage 2
• Obtain cultures early to identify resistant organisms 3
• Monitor closely for progression to osteomyelitis, as nail folds are anatomically close to phalanges 4

Severe or Refractory Cases

For pyogenic granulomas:

• Scoop-shave removal with hyfrecation or silver nitrate application 1
• Topical timolol 0.5% gel twice daily under occlusion for one month achieves complete clearance in reported cases 1

For recurrent or treatment-refractory lesions:

• Intralesional triamcinolone acetonide 5–10 mg/cc 5, 1
• Consider partial nail-plate avulsion for intolerable grade 2–3 disease 1

Follow-Up Protocol

• Reassess after 2 weeks of therapy 1, 3
• If no clinical improvement at 2 weeks, intensify treatment or refer to dermatology/podiatry 1

Prevention Strategies

• Avoid nail biting or trimming nails excessively short 1
• Trim nails straight across and keep them of adequate length 1
• Apply topical moisturizers daily to cuticles and periungual tissues 1
• Wear protective gloves during cleaning or prolonged water/chemical exposure 1
• For toenail involvement: Wear comfortable, well-fitting shoes and cotton socks 1