Oral Antibiotics for Severe Paronychia
For severe (grade 3) paronychia, oral antibiotics targeting Staphylococcus aureus are indicated when infection is suspected, with first-line options being cephalexin 250 mg four times daily or dicloxacillin 250 mg four times daily for penicillin-tolerant patients, and clindamycin 300-400 mg three times daily for penicillin-allergic patients. 1
When to Use Oral Antibiotics
Oral antibiotics are specifically indicated for grade 2 or higher paronychia when infection is suspected, but always obtain bacterial/viral/fungal cultures first before initiating therapy, as secondary bacterial or mycological superinfections occur in up to 25% of cases involving both gram-positive and gram-negative organisms. 2, 3
Severe paronychia (grade ≥3) is defined as requiring surgical intervention or antibiotics, with limitation of self-care activities of daily living. 2
Recognize that many cases of paronychia—particularly chronic or drug-induced forms—are primarily inflammatory rather than infectious, and systemic antibiotics should not be used routinely unless infection is proven. 4
Specific Antibiotic Regimens
First-Line Options (Penicillin-Tolerant)
Cephalexin 250 mg four times daily is the preferred first-line agent targeting Staphylococcus aureus. 1
Dicloxacillin 250 mg four times daily serves as an alternative first-line option with similar coverage. 1
Penicillin-Allergic Patients
- Clindamycin 300-400 mg three times daily is the recommended alternative for patients with penicillin allergy. 1
MRSA or Treatment Failure
Doxycycline 100 mg twice daily should be considered for suspected persistent MRSA or when initial antibiotic therapy fails. 1
If trimethoprim-sulfamethoxazole (Bactrim) has already failed, switch to one of the above alternatives rather than continuing the same class. 1
Essential Concurrent Topical Therapy
Continue topical povidone iodine 2% twice daily as the most evidence-based antiseptic agent, even when using oral antibiotics. 2, 3, 1
Apply combination topical antibiotics with mid-to-high potency corticosteroid ointment to nail folds twice daily, but avoid topical steroids if purulent drainage is present until infection is adequately treated. 3
Use dilute vinegar soaks (50:50 dilution) for 10-15 minutes twice daily as an adjunctive antiseptic measure. 3, 1
Critical Monitoring and Escalation
Reassess after 2 weeks of antibiotic therapy; if reactions worsen or fail to improve, proceed to surgical intervention including partial nail avulsion. 2, 3, 1
Consider interrupting the causative drug (if drug-induced) until severity returns to grade 0-1. 2
Surgical drainage is often required when an abscess has formed, and oral antibiotics alone are usually insufficient without adequate drainage unless the patient is immunocompromised. 5
Common Pitfalls to Avoid
Do not prescribe oral antibiotics for paronychia associated with ingrown toenails unless infection is proven, as systemic antibiotics are ineffective for the mechanical problem. 4, 6
Do not continue ineffective antibiotics beyond 2 weeks—culture results should guide therapy adjustment, particularly for resistant organisms. 1
Recognize that chronic paronychia (symptoms ≥6 weeks) represents an irritant dermatitis rather than infection and requires topical steroids or calcineurin inhibitors, not antibiotics. 5
In pediatric patients with finger-sucking or nail-biting habits, consider mixed anaerobic and aerobic infections requiring broader coverage with amoxicillin-clavulanate. 7