How should I diagnose and manage an ingrown toenail in an adolescent or adult who wears tight shoes, trims nails too short, and may have diabetes, peripheral vascular disease, or immunosuppression?

Ingrown Toenail: Diagnosis and Management

Diagnosis

Ingrown toenail (onychocryptosis) is a clinical diagnosis based on the characteristic finding of the nail edge growing into the periungual dermis, most commonly affecting the hallux, with pain, swelling, and discharge as the primary features. 1, 2

Key Diagnostic Features

• Pain localized to the lateral nail fold with visible penetration of the nail edge into the surrounding soft tissue 1
• Erythema and edema of the lateral nail fold, progressing to granulation tissue formation in advanced stages 3
• Purulent discharge when secondary bacterial infection is present 1
• Four clinical stages guide treatment decisions: Stage 1 shows erythema and edema; Stage 2 adds infection and drainage; Stage 3 includes chronic inflammation with granulation tissue; Stage 4 involves lateral nail fold hypertrophy 1

Critical Differential Diagnoses to Exclude

• Subungual exostosis (bony growth under the nail) 1
• Nail bed tumors including melanoma 1
• Paronychia (infection of the nail fold without nail plate penetration) 4

Special Populations Requiring Enhanced Assessment

In patients with diabetes, peripheral vascular disease, or immunosuppression, immediately assess vascular status and infection severity, as these conditions dramatically increase the risk of limb-threatening complications. 4

• Check pedal pulses bilaterally and measure ankle-brachial index if pulses are diminished or absent 4
• Assess for peripheral neuropathy using 10-gram monofilament testing, as sensory loss may mask the severity of injury 4
• Screen for diabetes with fasting glucose or HbA1c if not previously diagnosed, as diabetics are three times more likely to develop complications from nail pathology 4, 5
• Examine for signs of deep infection including tracking erythema, lymphangitis, or systemic symptoms requiring urgent intervention 4

Management Algorithm

Stage 1 (Mild): Erythema and Edema Without Infection

Begin with conservative measures, which are effective in 70-80% of early-stage cases. 3, 2

• Correct footwear immediately: Ensure shoes are 1-2 cm longer than the foot with adequate width at the metatarsophalangeal joints 4
• Soak the affected toe in warm water for 10-15 minutes twice daily, followed by application of mid- to high-potency topical corticosteroid to reduce inflammation 3
• Place wisps of cotton or dental floss under the ingrown lateral nail edge after soaking to lift the nail away from the nail fold 3
• Apply gutter splint technique: Insert a vinyl tube (cut from IV tubing) along the lateral nail edge to separate it from the lateral fold, providing immediate pain relief 3, 2
• Instruct proper nail trimming: Cut nails straight across, never rounded, and not too short 4
• Manage hyperhidrosis if present with topical antiperspirants or drying agents 3

Stage 2 (Moderate): Infection Present

Add antimicrobial therapy while continuing conservative measures. 3

• Apply topical povidone iodine 2% twice daily to the affected area 4
• Consider oral antibiotics if cellulitis extends beyond the immediate nail fold or if the patient has diabetes or immunosuppression 4
• Continue gutter splinting or cotton nail cast technique (cotton with cyanoacrylate adhesive) 3
• Optimize glycemic control in diabetic patients, as poor glucose control perpetuates infection risk 5

Stage 3-4 (Severe): Granulation Tissue or Recurrent Disease

Surgical intervention is superior to conservative treatment for preventing recurrence in moderate to severe cases. 3, 2

Preferred Surgical Approach

Partial nail avulsion with phenol matricectomy is the most effective technique, with the lowest recurrence rates (typically <5%) and acceptable healing times. 1, 3, 6

Procedure steps:

• Perform digital block with 1-2% lidocaine without epinephrine 1
• Avulse the lateral 3-4mm of nail plate from the nail bed and matrix 3
• Apply 88% phenol to the exposed lateral matrix for 2-3 minutes to achieve chemical matricectomy 1, 6
• Neutralize with alcohol and allow healing by secondary intention 6
• Advantages: Lower recurrence rate than surgical excision alone, faster return to normal activities, and can be performed in office setting 3, 6

Alternative Surgical Options

• Surgical lateral matricectomy (without phenol) has higher recurrence rates but may be preferred if phenol is unavailable 3
• Electrosurgical matricectomy is an alternative to phenol but requires specialized equipment 3
• Total nail avulsion should be avoided as it has the highest recurrence rate and prolonged healing time 2

Special Considerations for High-Risk Patients

Diabetic Patients

Diabetic patients require aggressive early intervention and close monitoring due to the risk of progression to limb-threatening infection. 4

• Lower threshold for surgical intervention rather than prolonged conservative management 4
• Ensure adequate vascular supply before any surgical procedure; if ankle-brachial index <0.9 or toe pressure <30 mmHg, obtain vascular surgery consultation 4
• Provide meticulous post-procedure wound care with daily inspection and dressing changes 4
• Refer to podiatry or foot care specialist for ongoing preventive nail care 4

Immunosuppressed Patients

Immunosuppression dramatically increases susceptibility to infection and complications. 5

• Maintain low threshold for oral antibiotics even with minimal signs of infection 5
• Consider HIV testing if risk factors are present and immune status is unknown 5
• Coordinate with primary team managing immunosuppression regarding infection risk 5

Prevention of Recurrence

After successful treatment, implement preventive strategies to avoid recurrence. 4

• Educate on proper nail trimming: Cut straight across, never rounded, and not too short 4
• Ensure appropriate footwear: Avoid tight shoes and ensure adequate toe box space 4
• Apply daily topical emollients to cuticles and periungual tissues to prevent cracking 4, 5
• Avoid walking barefoot or in thin-soled slippers, especially in high-risk patients 4
• Treat underlying conditions: Manage hyperhidrosis, onychomycosis, and optimize diabetes control 4, 5, 3
• Regular foot examinations: At least annually for diabetic patients, beginning at puberty 4

Common Pitfalls to Avoid

• Do not delay surgical intervention in recurrent cases or when conservative measures fail after 2-4 weeks, as prolonged inflammation increases morbidity 3, 2
• Do not perform total nail avulsion as first-line surgical treatment due to high recurrence rates 2
• Do not overlook vascular assessment in diabetic or elderly patients before surgical intervention 4
• Do not assume infection is absent in diabetic patients with neuropathy, as pain may be diminished despite significant infection 4
• Do not neglect patient education on proper nail care and footwear, as these are the primary modifiable risk factors 4, 3