What are the treatment options for actinic keratosis on the ear and cheek?

Treatment Options for Actinic Keratosis on the Ear and Cheek

For actinic keratosis on the ear and cheek, the recommended first-line treatments are cryosurgery for isolated lesions or field-directed therapy with 5-fluorouracil or imiquimod for multiple lesions, based on the 2021 American Academy of Dermatology guidelines. 1

Treatment Selection Based on Lesion Characteristics

Isolated Lesions (Lesion-Directed Approach)

• Cryosurgery is strongly recommended as first-line treatment for isolated AKs on the ear and cheek, with high efficacy and convenience of a single office visit 1
• Curettage may be warranted for thicker (grade 3) AKs on the ear, especially when there is suspicion of early squamous cell carcinoma (SCC) - histology must always be obtained 1
• The ear requires special consideration due to higher risk of metastasis when SCC develops at this site 1

Multiple Lesions (Field-Directed Approach)

• Field-directed therapy is recommended when multiple AKs are present in a contiguous area 1
• Strong recommendations (with moderate quality evidence) for field treatment include:
  • 5-fluorouracil (5-FU) - highest efficacy rating for field treatment 1
  • Imiquimod - also highly effective for field treatment 1, 2
• Conditional recommendations (with lower quality evidence) include:
  • Diclofenac gel 1
  • Photodynamic therapy (PDT) with aminolevulinic acid (ALA) 1, 3

Treatment Considerations for Specific Sites

Ear

• Requires careful consideration due to higher risk of progression to SCC and higher metastatic potential 1
• Histological diagnosis of thicker AKs is recommended to differentiate from invasive SCC 1
• Cryosurgery is rated as excellent treatment for ear lesions 1
• For multiple lesions on the ear, field therapy with 5-FU or imiquimod may be appropriate 1

Cheek/Face

• Cryosurgery, 5-FU, and imiquimod all receive excellent ratings for facial lesions 1
• PDT is conditionally recommended and may provide superior cosmetic outcomes on the face 1
• Periocular lesions require special caution to avoid eye exposure with topical agents 1

Combination Approaches

• The combined use of 5-FU and cryosurgery is conditionally recommended over cryosurgery alone (moderate quality evidence) 1
• The combined use of imiquimod and cryosurgery is conditionally recommended over cryosurgery alone (low quality evidence) 1
• Sequential therapy may provide enhanced efficacy for resistant or recurrent lesions 1

Treatment Algorithms

For Isolated Lesions:

1. First-line: Cryosurgery with liquid nitrogen 1
2. For thick or suspicious lesions: Curettage with histological examination 1
3. For resistant lesions: Consider combination therapy with cryosurgery plus topical agent 1

For Multiple Lesions:

1. First-line field therapy: 5-fluorouracil or imiquimod 1
   • 5-FU: Various concentrations (0.5-5%) applied daily or twice daily for 2-4 weeks 1
   • Imiquimod: 5% cream applied 2-3 times weekly for 4-16 weeks or 2.5-3.75% daily for 2-3 weeks 1
2. Second-line: Photodynamic therapy with ALA 1, 3
3. Alternative: Diclofenac gel 1

Important Considerations and Pitfalls

• AKs have a recurrence rate estimated to be as high as 50% within the first year, necessitating ongoing monitoring and treatment 1
• The risk of progression of AK to SCC varies from less than 0.1% to 20%, with higher risk on the ear 1
• UV protection is strongly recommended for all patients with AKs to prevent new lesions 1
• Patient factors including compliance, ability to tolerate side effects, and preferred treatment duration should be considered 1
• Topical agents should be used with caution near the eyes due to risk of irritation 1
• For immunosuppressed patients or those with a history of skin cancer, more aggressive treatment and closer monitoring may be warranted 1, 4

By selecting the appropriate treatment based on lesion characteristics, location, and patient factors, actinic keratoses on the ear and cheek can be effectively managed to reduce the risk of progression to invasive squamous cell carcinoma.