What is the best course of treatment for a 15-year-old female patient with a swollen left middle finger, specifically in the nail area, accompanied by pain and restricted movement, who has a past medical history (PMHx) of eczema, treated with Mometasone Furoate (generic name: Mometasone Furoate) as needed, and a possible allergy to chicken, and who was initially given Mefenamic acid (generic name: Mefenamic acid) with partial pain relief?

Treatment of Acute Bacterial Paronychia in a 15-Year-Old Female

This patient requires immediate incision and drainage of the abscess combined with oral antibiotics, specifically cephalexin or amoxicillin-clavulanate (Augmentin 500/125 mg every 12 hours), along with warm water soaks and topical antiseptic therapy. 1

Immediate Management: Surgical Drainage

• Any abscess formation mandates drainage, which is the cornerstone of treatment for acute paronychia with localized pus collection 1, 2
• Drainage options range from simple instrumentation with a hypodermic needle to wide incision with a scalpel, depending on abscess size and location 1, 3
• The presence of a visible pus collection under the skin beside the nail, as described in this case, requires procedural intervention rather than conservative management alone 1

Antibiotic Therapy

Oral antibiotics are indicated in this case because there is clear evidence of infection (localized pus collection with erythematous border) and the patient has functional impairment (unable to move digit) 1

First-Line Antibiotic Choice:

• Cephalexin or amoxicillin-clavulanate (Augmentin 500/125 mg every 12 hours) are the preferred first-line oral antibiotics 1
• These agents provide coverage for the most common pathogens: Staphylococcus aureus and Streptococcus species 1, 3

Important Consideration:

• Obtain bacterial cultures from the purulent drainage before initiating antibiotics to guide therapy if initial treatment fails 1, 2
• Up to 25% of paronychia cases have secondary bacterial or mycological superinfections involving both gram-positive and gram-negative organisms 4, 1, 2

If Initial Treatment Fails:

• Switch to sulfamethoxazole-trimethoprim (Bactrim) if cephalexin fails, as it provides broader coverage including MRSA 1
• Clindamycin should be avoided as it lacks adequate coverage for some streptococcal species and has increasing resistance patterns 1

Adjunctive Topical Therapy

After drainage, implement the following topical regimen:

• Warm water soaks for 15 minutes 3-4 times daily or white vinegar soaks (1:1 dilution) for 15 minutes daily 1, 3
• Topical povidone iodine 2% twice daily to the affected area as the most evidence-based antiseptic agent 1, 2
• Mid-to-high potency topical corticosteroid ointment (such as the mometasone furoate she already has) applied to nail folds twice daily to reduce inflammation 1, 2

Critical Caveat:

• Avoid topical steroids if purulent drainage is present until infection is adequately treated (i.e., after drainage and initiation of antibiotics) 2

Why Conservative Management Alone is Insufficient

The provided guidelines are clear that this patient's presentation requires more than topical therapy:

• The presence of a localized pus collection is an absolute indication for drainage 1, 3
• Oral antibiotics are usually not needed if adequate drainage is achieved, but this patient has significant functional impairment (unable to move digit) and clear signs of infection, making systemic antibiotics appropriate 1, 3
• Simple warm soaks and topical antibiotics are reserved for early paronychia without abscess formation 1, 3

Follow-Up Protocol

• Reassess after 2 weeks of treatment 1, 5
• If no improvement is seen, consider referral to dermatology or hand surgery for further evaluation 1, 5
• If reactions worsen or do not improve, escalate therapy to the next level 1

Patient Education for Prevention

Counsel the patient on the following measures to prevent recurrence:

• Avoid biting nails or cutting nails too short 1
• Regular trimming of nails ensuring they are straight and not too short 1
• Daily application of topical emollients to cuticles and periungual tissues 1
• Avoid repeated friction and trauma/excessive pressure 4
• Wear gloves while cleaning 4, 1

Regarding the Mefenamic Acid

The mefenamic acid provided by the school nurse was appropriate for pain management but does not address the underlying infection 6. Continue pain control as needed, but the primary treatment must focus on drainage and antibiotics.

Regarding Her Eczema History

Her history of eczema treated with mometasone furoate is not directly related to this acute bacterial paronychia 7, 8. However, the mometasone can be repurposed as part of the anti-inflammatory component of paronychia treatment after the infection is controlled 1, 2.