Persistent Non-Healing Scab on Finger: Evaluation and Management
A non-healing scab on the dorsal finger persisting for 2 months in an otherwise healthy adult warrants biopsy to exclude squamous cell carcinoma or other malignancy, as any wound lasting longer than 4 weeks should raise suspicion for underlying pathology. 1
Immediate Clinical Assessment
Key features that indicate malignancy:
- Non-healing wound lasting >4 weeks (your case is at 8 weeks) 1
- Rapidly growing or heaped-up appearance resembling exuberant granulation tissue 1
- Deep, punched-out ulcer with raised or rolled edges 1
- Hyperkeratosis surrounded by raised skin 1
- Altered sensation (tingling or increased pain) relative to normal wounds 1
Diagnostic Approach
Obtain tissue diagnosis early through biopsy to evaluate for histological and microbiological causes, as this is essential when skin lesions fail to respond to standard wound care. 1 The differential diagnosis for a persistent finger lesion includes:
- Squamous cell carcinoma – particularly concerning given the 2-month duration and dorsal hand location (sun-exposed area) 1
- Actinic keratosis – precancerous lesion on sun-exposed dorsal hand 1
- Herpetic whitlow – can present with persistent vesicles/crusting on fingers, though typically more acute 2
- Atypical infection in immunocompromised hosts (fungal, mycobacterial) 1, 3
- Vascular insufficiency – though less likely without systemic disease 4
When to Refer to Dermatology
Refer urgently (2-week cancer pathway) if the lesion demonstrates: 1
- Bleeding 1
- Pain 1
- Thickened substance when held between finger and thumb 1
- Failure to respond to 4 weeks of standard wound care 1
Your case meets criteria for urgent referral given the 2-month duration without healing.
Management Algorithm
Step 1: Immediate referral to dermatology for biopsy via the urgent cancer pathway, as lesions concerning for SCC require specialist evaluation within 2 weeks. 1
Step 2: Biopsy technique should include both histological assessment and microbial cultures (bacterial, fungal, viral) to identify infectious etiologies. 1
Step 3: Avoid destructive treatment (cryotherapy, curettage) until tissue diagnosis is obtained, as this may compromise diagnostic accuracy and delay appropriate cancer treatment. 1
Tetanus Status
Your tetanus immunization is adequate – no booster is needed for this wound since you are up-to-date with Td vaccination. For clean wounds in patients with ≥3 previous doses, a booster is only indicated if ≥10 years have elapsed since the last dose. 5 Even if this were classified as a contaminated wound, a booster would only be needed if ≥5 years had passed. 5
Critical Clinical Pearls
Do not assume this is simply a "slow-healing wound" – any lesion on sun-exposed skin (dorsal hand) that fails to heal within 4 weeks requires tissue diagnosis to exclude malignancy. 1 The dorsal hand is a common site for both actinic keratosis and squamous cell carcinoma due to cumulative UV exposure. 1
Avoid empiric antibiotic treatment without tissue diagnosis, as this may mask underlying pathology and delay appropriate cancer treatment. 1 Proper wound cleaning is important, but antibiotics are not indicated for tetanus prevention. 5
Document the lesion with photography and precise anatomic location before biopsy to enable monitoring of treatment response or disease evolution. 1