What is the best treatment approach for a patient with an infected ingrown toenail, potentially with underlying conditions such as diabetes?

Treatment of Infected Ingrown Toenail

For an infected ingrown toenail, immediately perform sharp debridement to remove the offending nail spicule and start oral antibiotics targeting Staphylococcus aureus and streptococci (such as cephalexin, dicloxacillin, or clindamycin) for 1-2 weeks, with escalation to parenteral therapy only if systemic signs develop. 1

Immediate Assessment and Risk Stratification

Before initiating treatment, assess infection severity and patient risk factors:

• Examine for local signs of infection: erythema, pain, swelling, purulence, and warmth around the nail fold 1
• Check for systemic toxicity: fever, tachycardia, hypotension, confusion, or metabolic instability that would require hospitalization 1, 2
• In diabetic or prediabetic patients specifically: test protective sensation with monofilament, palpate pedal pulses, and check capillary refill to assess for neuropathy and peripheral arterial disease 1
• Probe the depth of infection: determine if infection extends beyond the nail fold into deeper tissues 1

This assessment determines whether outpatient oral therapy is appropriate or if hospitalization with parenteral antibiotics is needed.

Culture Collection (Before Antibiotics)

Obtain cultures before starting antibiotics, but only after proper wound preparation:

• Cleanse and debride the lesion first to avoid contamination with colonizing organisms 1
• Obtain tissue specimens from the debrided base using curettage with a sterile dermal curette or scalpel blade—this is the gold standard 1
• Avoid swabbing undebrided wounds or drainage as these yield unreliable results contaminated with surface flora 1, 2
• Send specimens promptly in appropriate sterile containers for both aerobic and anaerobic culture 1

Definitive Local Treatment (The Critical Step)

Sharp debridement is essential and often more important than antibiotics alone:

• Remove the offending nail spicule completely from the lateral nail fold using scalpel or nail nippers 1, 3
• Excise any granulation tissue and necrotic material at the nail border 1
• Consider partial nail avulsion if the infection is recurrent or severe and conservative measures have failed 1, 4
• For recurrent cases: partial nail avulsion with phenol matricectomy is significantly more effective than surgery alone in preventing recurrence (14% vs 41% recurrence rate, RR 0.34) 4

Common pitfall: Antibiotics alone without adequate debridement will fail. The mechanical removal of the embedded nail is the definitive treatment. 5

Empirical Antibiotic Selection

For mild to moderate infections without systemic signs:

• Start oral antibiotics targeting gram-positive cocci: cephalexin, dicloxacillin, or clindamycin for 1-2 weeks 1, 5
• Cover Staphylococcus aureus and streptococci as these are the predominant pathogens 1
• Consider MRSA coverage (trimethoprim-sulfamethoxazole, doxycycline, or linezolid) if there is local high prevalence or previous MRSA infection 1

For severe infections with systemic signs:

• Initiate parenteral therapy with broad-spectrum coverage, then switch to oral when responding 5
• Continue antibiotics until infection resolves (1-2 weeks for mild infections), not necessarily until complete wound healing 1, 5

Important caveat: Topical antibiotics alone are insufficient for infected ingrown toenails. While topical antimicrobial peptides showed 85-90% clinical improvement in diabetic foot ulcers 5, infected ingrown toenails require systemic therapy due to deeper tissue involvement.

Wound Care and Off-Loading

• Dress the wound to allow daily inspection and maintain a moist healing environment 1
• Off-load pressure from the affected toe using appropriate footwear or padding 1
• Instruct the patient to avoid barefoot walking and wear properly fitting shoes that accommodate the toe 1

When to Escalate Care

Hospitalize or consult surgery immediately if:

• Systemic toxicity develops: fever, leukocytosis, or metabolic instability 1, 2
• Deep abscess forms or infection extends to bone or joint 1, 2
• Infection fails to respond to initial therapy within 3-5 days 1, 2
• Critical ischemia is present in diabetic patients, requiring urgent vascular evaluation 1, 2

Follow-Up Protocol

• Re-evaluate in 3-5 days to assess response to therapy 1
• Adjust antibiotics based on culture results and clinical response 1
• For diabetic/prediabetic patients: establish regular foot screening every 6-12 months to monitor for development of neuropathy or vascular disease 1

Prevention Education

• Teach proper nail trimming technique: cut nails straight across, not too short, and avoid rounding the corners 1
• Instruct daily foot inspection to examine for early signs of redness, swelling, or drainage 1
• Emphasize immediate reporting of any problems that develop 1
• Recommend appropriate footwear that fits properly and accommodates foot shape without compressing toes 1

Critical distinction for diabetic patients: While the general approach is similar, diabetic patients require more aggressive monitoring and lower threshold for hospitalization due to risk of rapid progression to limb-threatening infection. 5