What is the diagnosis and treatment for a tender, red spot on the finger that is tender to touch?

Differential Diagnosis and Management of Tender Red Spot on Finger

This presentation most likely represents acute paronychia (nail fold infection), herpetic whitlow, or a localized felon, and initial management should focus on distinguishing between infectious causes that require antibiotics versus viral causes that need only supportive care.

Primary Differential Diagnoses

Acute Paronychia (Most Common)

• Presents as painful erythematous inflammation with swelling and tenderness of the lateral or proximal nail folds 1
• Secondary bacterial infection occurs in up to 25% of cases, with both gram-positive and gram-negative organisms implicated 1
• The condition often follows minor trauma or manipulation of the cuticle 1

Herpetic Whitlow (Critical to Exclude)

• Finger lesions from herpes simplex virus often mimic pyogenic infection but must be differentiated to avoid unnecessary surgical drainage 2
• Typically affects medical or dental personnel with direct digital contact to oral-respiratory systems 2
• Lesions resolve spontaneously within 1-3 weeks with only supportive treatment 2
• Surgical drainage of herpetic whitlow is contraindicated and can worsen outcomes 2

Felon (Deep Pulp Space Infection)

• Presents as intense pain and swelling of the fingertip pulp 3, 4
• Requires urgent surgical drainage if fluctuance or abscess formation is present 3, 4

Initial Assessment Approach

Key Clinical Features to Identify

Location specificity:

• Nail fold involvement suggests paronychia 1
• Fingertip pulp involvement suggests felon 3, 4
• Grouped vesicles on an erythematous base suggest herpetic whitlow 2

Occupational history:

• Healthcare or dental workers have higher risk of herpetic whitlow 2
• Frequent water exposure increases paronychia risk 1

Presence of vesicles or pustules:

• Clear vesicles strongly suggest viral etiology (herpetic whitlow) 2
• Purulent discharge suggests bacterial paronychia 1

Treatment Algorithm

Grade 1 Paronychia (Mild: Nail fold edema/erythema without discharge)

Continue monitoring and initiate conservative management 1:

• Apply topical povidone iodine 2% twice daily 1, 5
• Apply topical antibiotics combined with mid-to-high potency corticosteroid ointment twice daily 1, 5
• Reassess after 2 weeks 1

Grade 2 Paronychia (Moderate: Pain with discharge or nail separation)

Obtain bacterial/viral/fungal cultures if infection is suspected 1:

• Continue topical povidone iodine 2% 1
• Add oral antibiotics covering Staphylococcus aureus and gram-positive organisms 1, 5
• Consider amoxicillin-clavulanate as first-line oral agent 5
• Reassess after 2 weeks 1

Grade 3 or Intolerable Grade 2 (Severe: Surgical intervention indicated)

Interrupt any causative medications and obtain cultures 1:

• Continue topical antiseptics and antibiotics 1
• Oral antibiotics are mandatory 1
• Consider partial nail avulsion if conservative measures fail 1
• Surgical drainage under digital anesthesia with extensive lavage for felon 4

Suspected Herpetic Whitlow

Provide supportive care only—no surgical intervention 2:

• Symptoms resolve spontaneously within 1-3 weeks 2
• Avoid incision and drainage, which is contraindicated 2
• Educate patient about recurrence risk (can occur years later) 2

Preventive Education (Essential for All Patients)

Provide gentle skin care instructions 1, 5:

• Trim nails straight across, never rounded, and avoid cutting too short 5
• Wear gloves during cleaning activities 1, 5
• Avoid nail biting or cuticle manipulation 1, 5
• Apply topical emollients daily to cuticles and periungual tissues 1
• Wear comfortable, well-fitting shoes (for toe involvement) 1, 5

Red Flags Requiring Specialist Referral

Refer to hand surgeon when 1, 3:

• Failure to respond to standard treatments after 2-4 weeks 1
• Suspected deep space infection (felon) with fluctuance 3, 4
• Severe pain suggesting vascular compromise or ischemia 3
• Concern for flexor tenosynovitis (pain with passive extension, fusiform swelling) 3
• Immunosuppressed patients with persistent infection 1

Urgent referral (within 2 weeks) if 1:

• Lesion is bleeding, extremely painful, or thickened with palpable substance suggesting possible malignancy 1

Common Pitfalls to Avoid

• Never surgically drain suspected herpetic whitlow—this worsens outcomes and is the most critical error 2
• Do not assume all finger infections are bacterial; viral etiologies require completely different management 2
• Avoid prescribing antibiotics for herpetic whitlow, as they provide no benefit 2
• Do not delay surgical consultation for suspected felon, as tissue viability depends on prompt intervention 3
• Obtain cultures before starting antibiotics when possible to guide therapy 1, 4

Follow-Up Monitoring

Reassess at 5-7 days (first dressing change) 4:

• Monitor for progression of erythema, increased pain, or systemic symptoms 4
• If worsening or no improvement, escalate treatment or refer 1

Recontact at 1 month 4:

• Assess for complete resolution, residual pain, stiffness, or recurrence 4
• Monitor for development of pyogenic granuloma, which may require additional intervention 1, 5