What is the appropriate management for a 54-year-old male with rough, bumpy, scaly, and slightly pearlescent skin lesions on the tops of his ears that become red in the sun?

Management of Actinic Keratosis on the Ears

This patient has actinic keratosis (AK) on the ears requiring treatment with either cryotherapy or field-directed topical therapy, combined with strict photoprotection and ongoing surveillance for progression to squamous cell carcinoma.

Clinical Diagnosis

The presentation of rough, bumpy, scaly, slightly pearlescent lesions on sun-exposed areas (ear tops) that become red with sun exposure is pathognomonic for actinic keratosis 1. The ears are a high-risk location for AKs due to chronic UV exposure, particularly in men with thinning hair 1. At age 54 with these findings, this patient demonstrates field cancerization—widespread actinic damage that predisposes to multiple AKs and increased skin cancer risk 1.

Treatment Options

Lesion-Directed Therapy: Cryotherapy

• Liquid nitrogen cryotherapy is the standard first-line treatment for individual AKs on the ears 1
• Apply liquid nitrogen for 5-20 seconds per lesion depending on thickness, using a freeze-thaw-freeze cycle for optimal efficacy 1
• Expect 50% of lesions to require 2-3 treatments, with approximately 10% recurrence rate 1
• Cryotherapy carries a 25% risk of ulceration and/or infection, particularly on the ears where healing can be delayed 1

Field-Directed Therapy: Topical Agents

• For multiple or confluent AKs on the ears, topical 5-fluorouracil 5% cream applied twice daily for 2-4 weeks is highly effective 2
• Treatment should continue until the inflammatory response reaches the erosion stage, then discontinue 2
• Complete healing may take 1-2 months after stopping therapy 2
• Alternative field therapy includes imiquimod, with optimal assessment at 10 weeks post-treatment 1

Photodynamic Therapy (PDT)

• Consider PDT for multiple AKs at sites of poor healing (like the ears) or with poor response to standard therapies 1
• PDT is particularly useful when cosmetic outcome is a priority 1

Critical Management Considerations

Biopsy Indications

• Perform biopsy (shave, curettage, or formal excision) if there is diagnostic uncertainty or failure to respond to first-line treatment 1
• Any lesion with induration, ulceration, rapid growth, or diameter >1 cm warrants biopsy to exclude squamous cell carcinoma 1
• The ears have higher rates of AK progression to invasive SCC compared to other sites 1

Photoprotection (Essential)

• Strict sun avoidance and photoprotection are mandatory, as successful AK treatment is associated with lower skin cancer incidence 1
• Recommend broad-spectrum sunscreen, wide-brimmed hats, and avoidance of peak sun hours 1

Surveillance Strategy

• This patient requires long-term follow-up due to increased risk of non-melanoma skin cancer 1
• Schedule follow-up at 3-6 months initially, then every 6-12 months for total body skin examination 1
• AKs have a spontaneous regression rate of 15-63% per year but recur in up to 50% within the first year 1
• Educate the patient to self-monitor for new lesions or changes suggesting progression to SCC (bleeding, tenderness, rapid growth, non-healing) 1

Common Pitfalls to Avoid

• Never perform partial or shave biopsy of suspicious nodular lesions—complete excision is required for accurate histologic assessment if malignancy is suspected 3, 4
• Do not ignore field cancerization: treating individual lesions without addressing the entire sun-damaged field leads to continued development of new AKs 1
• Avoid neomycin-containing topical preparations, as 5-15% of patients with chronic external ear conditions develop contact sensitization 1
• Do not reassure and dismiss: AKs represent premalignant lesions with variable but real progression risk to invasive SCC, particularly in immunocompetent older males with chronic sun damage 1

Treatment Algorithm

1. For 1-5 discrete lesions: Cryotherapy as first-line 1
2. For >5 lesions or confluent involvement: Field-directed topical therapy (5-FU or imiquimod) 1, 2
3. If treatment failure after 2-3 attempts: Obtain biopsy to exclude SCC 1
4. If multiple recurrences or poor healing: Consider PDT 1
5. All patients: Implement strict photoprotection and establish surveillance schedule 1