What are the best treatment options for an adult with toenail pain, potentially caused by an underlying condition such as diabetes or poor circulation?

Toenail Pain in Adults: Evaluation and Management

For an adult presenting with toenail pain, immediately perform a comprehensive foot examination including inspection for ingrown nails, fungal infection, trauma, and signs of infection, while simultaneously assessing for underlying diabetes or peripheral arterial disease that could complicate treatment and increase amputation risk. 1

Initial Assessment Priority

The evaluation must distinguish between simple mechanical causes (ingrown toenail, trauma, ill-fitting footwear) and complications related to systemic disease, particularly diabetes with neuropathy or vascular insufficiency. 1

Key History Elements to Obtain

• Diabetes status: Duration of diabetes, current HbA1c, history of neuropathy or prior foot ulcers 1
• Vascular symptoms: Leg fatigue, claudication, rest pain, or history of vascular procedures 1
• Neuropathy symptoms: Numbness, burning, tingling, or loss of protective sensation 1
• Prior foot complications: Previous ulceration, amputation, Charcot foot, or infections 1
• Smoking history: Major risk factor for both PAD and poor wound healing 1
• Visual impairment or chronic kidney disease: Both increase foot complication risk 1

Physical Examination Components

Nail and skin inspection 1:

• Examine for ingrown nail borders, paronychia, subungual hematoma, or onychomycosis
• Assess for surrounding cellulitis, erythema, warmth, or purulent drainage
• Look for callus formation, pre-ulcerative lesions, or skin breakdown 2

Neurological assessment 1:

• 10-g monofilament testing to detect loss of protective sensation
• At least one additional test: pinprick, temperature sensation, or vibration with 128-Hz tuning fork
• Patients unable to feel the monofilament are at high risk for ulceration 2

Vascular assessment 1:

• Palpate dorsalis pedis and posterior tibial pulses bilaterally
• Assess capillary refill time, rubor on dependency, and pallor on elevation
• If pulses are diminished or absent, refer for ankle-brachial index testing 1

Structural assessment 2:

• Identify foot deformities (hammertoes, bunions, prominent metatarsal heads, Charcot foot)
• These deformities increase plantar pressure and ulceration risk 2

Management Algorithm Based on Findings

For Non-Diabetic Patients or Diabetic Patients WITHOUT Neuropathy/PAD

Ingrown toenail without infection:

• Conservative management with warm soaks, proper nail trimming technique, and appropriate footwear
• If recurrent or severe, refer to podiatry for partial nail avulsion 1

Fungal infection (onychomycosis):

• Confirm diagnosis with KOH preparation or fungal culture
• Terbinafine 250 mg once daily for 12 weeks for toenail infection 3
• Monitor liver function tests before initiating treatment 3
• Advise patients that clinical improvement occurs months after treatment completion due to nail growth time 3

Traumatic injury:

• Manage based on severity; ensure tetanus prophylaxis is current
• Monitor for secondary infection

For Diabetic Patients WITH Neuropathy or PAD (High-Risk Foot)

This population requires urgent, aggressive management due to high amputation risk. 1

Immediate actions 1:

• If any signs of infection (erythema, warmth, purulent drainage, fever), classify severity:
  • Mild: Superficial with minimal cellulitis (<2 cm)
  • Moderate: Deeper infection or cellulitis >2 cm
  • Severe: Systemic signs of sepsis present
• For moderate or severe infection, obtain urgent surgical consultation for debridement 1
• Start empiric antibiotics immediately for any infection—do not delay for culture results 1

Vascular assessment 1:

• If ankle pressure <50 mmHg or ABI <0.5, arrange urgent vascular imaging and revascularization consultation 1
• Even without these critical values, if toe pressure <30 mmHg or TcPO2 <25 mmHg, consider revascularization 1

Offloading and protection 1:

• Prescribe specialized therapeutic footwear immediately for patients with loss of protective sensation 1
• For any ulceration, use non-removable knee-high offloading device (total contact cast or irremovable walker) 1
• Instruct patient to limit standing and walking; provide crutches if necessary 1

Multidisciplinary referral 1:

• Immediate podiatry referral for all high-risk diabetic patients with toenail pain 1
• Podiatrist should coordinate with endocrinology, vascular surgery, and infectious disease as needed 1
• This interprofessional approach significantly reduces amputation rates 1

Glycemic Optimization for Diabetic Patients

Poor glycemic control accelerates neuropathy progression and impairs wound healing. 1, 4

• Target HbA1c of 6-7% to prevent neuropathy progression, though this will not reverse existing nerve damage 4
• Optimize blood pressure and lipid control, as hypertension is an independent risk factor for diabetic peripheral neuropathy 4
• Consider weight loss interventions, as lifestyle modification improves neuropathy symptoms 4

Management of Neuropathic Pain (If Present)

If the patient reports burning, shooting pain, or dysesthesias suggesting neuropathic pain 1, 4:

First-line pharmacotherapy 1, 4:

• Pregabalin: Start 75 mg twice daily, titrate to 150-300 mg twice daily (300-600 mg/day total) 1, 4
• Duloxetine: 60 mg once daily, may increase to 120 mg/day if needed 1, 4
• Both are FDA-approved with Level A evidence for diabetic neuropathic pain 1, 4

Dose adjustment considerations 4, 5:

• Pregabalin and gabapentin require renal dose adjustment in patients with CrCl <60 mL/min 5
• Duloxetine should be avoided in patients with hepatic disease 4

If first-line agents fail 1, 4:

• Consider tricyclic antidepressants (amitriptyline 25-75 mg/day), but avoid in elderly patients due to anticholinergic effects 4
• Gabapentin 900-3600 mg/day in divided doses is an alternative 4, 5
• Avoid opioids including tramadol and tapentadol due to addiction risk and lack of long-term efficacy 4

Critical Pitfalls to Avoid

Do not dismiss toenail pain in diabetic patients as trivial 1, 2:

• Even minor trauma can progress rapidly to limb-threatening infection in patients with neuropathy and PAD 1, 2
• Up to 50% of diabetic peripheral neuropathy is asymptomatic, so absence of pain does not indicate absence of risk 1

Do not delay referral in high-risk patients 1:

• Patients with loss of protective sensation, prior ulceration, amputation, structural abnormalities, or PAD require immediate podiatry referral for lifelong surveillance 1
• Dialysis patients are at exceptionally high risk and need interprofessional foot care 1

Do not prescribe therapeutic footwear without ensuring patient compliance 1:

• Therapeutic footwear only prevents ulcers if actually worn by the patient 1
• Provide education on daily foot inspection and proper footwear use 1

Do not treat suspected osteomyelitis without proper evaluation 1:

• If bone is visible or palpable with sterile probe, or if deep/longstanding wound, obtain plain radiographs to screen for osteomyelitis 1
• Inadequately treated bone infection leads to treatment failure and amputation 1

Follow-Up Schedule

For high-risk diabetic patients 1:

• Inspect feet at every clinical visit (every 1-3 months) 1, 2
• Comprehensive foot examination with monofilament testing every 3-6 months 2
• Annual vascular assessment 2

For low-risk patients 1:

• Comprehensive foot evaluation at least annually 1
• More frequent screening if risk factors develop 1