Actinic Keratosis: How to Choose the Right Treatment

Actinic keratoses (AKs) are common precancerous spots caused by years of sun exposure. While most AKs remain stable, some can develop into squamous cell carcinoma. Fortunately, several safe and effective treatment options exist, including topical creams, photodynamic therapy (PDT), liquid nitrogen (cryotherapy), and curettage. Choosing the right approach depends on the number, thickness, and location of the lesions, as well as patient preferences.

1. Topical Creams

Examples: 5-fluorouracil (5-FU), imiquimod, diclofenac, sometimes combined with calcipotriene

Topical creams are ideal for field therapy, treating both visible and invisible precancerous cells across sun-damaged areas. They are particularly useful when:

• Multiple lesions cover a large area (forehead, scalp, cheeks, arms)
• Lesions are thin and superficial
• Patients want durable long-term clearance

Key points:

• Treatment duration: 2–6 weeks depending on cream, area, and reaction
• Redness, crusting, and peeling are expected; short breaks are safe
• Cure rates: 70–90%, with some of the most durable long-term responses compared to other therapies

Topical therapy is like spraying weeds across a lawn: it treats the visible spots and the hidden ones beneath the surface.

2. Photodynamic Therapy (PDT)

PDT uses a photosensitizing cream and light to destroy abnormal cells. It is often used when:

• There are multiple AKs in a sun-damaged area
• Rapid clearance of lesions is desired

Advantages:

• Effective for thin to moderately thick lesions
• Treats multiple lesions in one session

Considerations:

• Can be uncomfortable during light activation
• Typically reserved for visible AKs and moderate sun-damaged fields, rather than very thick lesions

While PDT is effective, topical therapy usually provides better long-term durability, reducing recurrence over time.

3. Liquid Nitrogen (Cryotherapy)

Liquid nitrogen freezes individual lesions and is often used for single or small clusters of AKs.

Best for:

• Discrete lesions
• Thin to moderately thick AKs
• Quick office-based treatment

Considerations:

• Can cause temporary blistering, redness, or pigment changes
• Less ideal for large fields of sun damage, where topical therapy or PDT is preferred

4. Curettage for Thicker or Hypertrophic AKs

Thicker, crusted, or hypertrophic lesions may not respond well to creams or PDT. Curettage involves:

• Scraping the lesion with a small instrument
• Optionally combining with electrocautery to control bleeding

This approach is typically reserved for solitary, thicker spots that cannot be effectively treated with field therapy alone.

How Dermatologists Decide Which Treatment to Use

Treatment selection depends on:

Number and distribution of lesions

• Single/few lesions → cryotherapy or curettage
• Multiple/widespread lesions → topical creams or PDT

Thickness of lesions

• Thin, superficial → creams or PDT
• Thick, hypertrophic → curettage or combined approaches

Durability

Topical therapies often provide the most durable long-term clearance, especially when treating an entire sun-damaged field

Patient preference and tolerance

• Topical creams require adherence at home
• PDT requires in-office sessions
• Cryotherapy is quick but treats only discrete spots

Previous treatment history

Recurrent or resistant lesions may need a different modality

Bottom Line

There is no single "best" treatment for actinic keratoses. Dermatologists often use a combination of approaches:

• Thin or multiple AKs across a sun-damaged field: topical creams (best long-term durability), PDT
• Individual lesions: cryotherapy
• Thicker, resistant lesions: curettage ± electrocautery

By tailoring treatment to lesion type, location, and patient needs, dermatologists maximize clearance while minimizing discomfort and recurrence.