What information should I provide to a patient with actinic keratosis regarding its cause, sun protection, treatment options, and recommended dermatology follow‑up?

Patient Education for Actinic Keratosis (AK)

What is Actinic Keratosis?

Actinic keratosis is an early form of skin cancer caused by chronic sun exposure that appears as rough, scaly patches on sun-exposed skin and carries a risk of progression to invasive squamous cell carcinoma. 1

• AK lesions are areas of abnormal skin cell growth that occur predominantly on chronically sun-exposed areas such as the face, scalp, ears, neck, hands, and forearms 1
• These lesions represent a spectrum along the continuum to invasive cancer, with individual progression rates varying from less than 0.1% to 20% depending on location 2, 3
• The ear is a particularly high-risk site where squamous cell carcinoma has a higher risk of metastasis than at other skin locations 4
• For every visible AK lesion, there may be up to 10 subclinical (invisible) lesions in the surrounding sun-damaged skin, creating what is called "field cancerization" 3

Why Sun Exposure Caused This

• Chronic ultraviolet (UV) radiation exposure from sunlight is the primary cause of AK 1, 5
• UV radiation causes specific genetic mutations (p53 mutations) in skin cells that lead to abnormal cell growth 1
• The surrounding skin has also been damaged by sun exposure, which is why new lesions commonly develop over time 3

Critical Sun Protection Measures

All patients with AK must use rigorous UV protection to prevent new lesions, including daily broad-spectrum sunscreen and protective clothing. 1, 4

• Wear wide-brimmed hats to protect the scalp, face, and ears 4, 6
• Apply broad-spectrum sunscreen daily to all sun-exposed areas 1, 6
• Wear protective clothing covering arms and legs when outdoors 5
• Avoid tanning salons completely 3
• UV protection is strongly recommended with high-quality evidence and is as important as treating existing lesions 1, 2

Treatment Options Your Dermatologist Will Discuss

For Single or Few Isolated Lesions (1-3 lesions):

Cryosurgery (freezing with liquid nitrogen) is the first-line treatment for isolated AK lesions, offering high efficacy with the convenience of a single office visit. 1, 4, 2

• Clearance rates range from 57% to 98.8% depending on follow-up duration 4, 6
• Longer freezing times (>20 seconds) achieve superior results (83% clearance) compared to shorter times (<5 seconds, 39% clearance) 4, 6
• This is a single-visit treatment performed in the office 2

For Multiple Lesions in a Contiguous Area (Field Treatment):

When multiple AK lesions are present in a contiguous area, field-directed therapy with topical 5-fluorouracil or imiquimod cream is strongly recommended. 1, 4, 2

5-Fluorouracil (5-FU) cream:

• This is the highest efficacy field treatment option available 1, 4
• Applied at home, typically for several weeks 1
• Achieves complete clearance in 55.4% of patients at 8 weeks post-treatment 6
• The 0.5% formulation in 10% salicylic acid is particularly useful for scalp lesions 6
• Approximately 50% of patients can discontinue treatment at 6 weeks due to lesion disappearance 6

Imiquimod cream:

• Also strongly recommended for field treatment 1, 4
• Complete clearance rates of 44-46%, with 76% of patients maintaining clearance at 12 months 6
• Applied at home according to prescribed schedule 1

Tirbanibulin:

• Newer option with the advantage of a much shorter treatment duration (5 consecutive days only) 4, 2
• Complete clearance rate of 49.3% at day 57 4, 6

For Thick or Suspicious Lesions:

• Curettage (scraping) or biopsy may be necessary to obtain tissue for examination under the microscope 1, 4
• This is especially important for thick lesions on the ear to rule out early invasive squamous cell carcinoma 4
• Histological examination helps differentiate thick AK from invasive cancer 4

Combination Approaches:

• Your dermatologist may recommend combining 5-fluorouracil or imiquimod with cryosurgery for better results 1, 4, 2
• These combination approaches are conditionally recommended over cryosurgery alone 2

What to Expect During Treatment

• Most topical treatments cause local skin reactions including redness, scaling, crusting, and discomfort 7
• These reactions are expected and indicate the treatment is working 7
• Treatment adherence is critical for success, even when side effects occur 7
• Your dermatologist will provide specific instructions for managing side effects 7

Warning Signs Requiring Immediate Evaluation

You must return promptly for evaluation if any lesion shows these concerning features, as they may indicate progression to invasive squamous cell carcinoma: 1

• Bleeding spontaneously or with minimal trauma 1
• Becoming painful 1
• Growing significantly in size 1
• Developing thickness or substance when held between finger and thumb 1
• Failing to respond to standard treatment 1

Follow-Up and Monitoring

AK is a chronic disease requiring ongoing monitoring because recurrence rates are as high as 50% within the first year after treatment. 6, 2

• Once you have AK, you will likely develop new lesions over time due to the field cancerization effect 1, 3
• Patients with 10 or more AK lesions have a threefold higher risk for squamous cell carcinoma and require shorter follow-up intervals 1, 6
• You should learn to monitor your own skin and report new or changing lesions promptly 1
• Regular dermatology follow-up is essential for early detection and treatment of new lesions 1, 6

When to See Your Dermatologist

Referral to or continued care with a dermatologist is warranted in these situations: 1

• AK fails to respond to standard treatments 1
• Multiple or relapsing AKs represent a management challenge 1
• You are immunosuppressed (organ transplant recipient or taking immunosuppressive medications) 1, 8
• Lesions show concerning features suggesting possible squamous cell carcinoma (bleeding, painful, or thickened) 1
• You have extensive disease requiring specialized management 1

Self-Care and Long-Term Management

• AK is managed rather than cured once present 1
• Patient education enables effective self-care with awareness of skin cancer risk and how to minimize it 1
• Most patients with mild AK can manage their disease with topical therapy prescribed by their primary care provider, with periodic dermatology review 1
• Corroboration of diagnosis with your healthcare provider is advisable before treating new lesions on your own 1
• Short-term therapies may need prescription renewal to ensure maintained efficacy 1