Principles of treatment of actinic keratoses

Actinic keratoses can remit spontaneously, particularly with vigilant sun protection. Treatment is not usually necessary, but indications for active treatment of actinic keratoses include:

• symptomatic lesions
• cosmetic reasons
• multiple extensive field keratoses for which invasive disease cannot be excluded.

Evidence that treatment of actinic keratoses reduces the subsequent risk of developing invasive squamous cell carcinoma is limited. There is some evidence that topical field treatment (eg topical fluorouracil) reduces this riskWeinstock, 2018.

Many treatments are available for actinic keratoses, and the choice depends on patient and lesion factors (eg site and extent of lesions, patient age, comorbidities [especially immunosuppression], patient preference, treatment cost).

First-line therapy for non-extensive actinic keratoses is usually cryotherapy with liquid nitrogen. Most actinic keratoses respond well to cryotherapy. However, avoid cryotherapy if the diagnosis is uncertain.

Curettage or shave excision produces good results in selected lesions, especially thicker hypertrophic keratoses and cutaneous horns.

For extensive or multiple (field) actinic keratoses, or intolerance of cryotherapy, consider topical field treatments (eg topical fluorouracil or imiquimod cream), or specialist referral. Specialist treatments include other topical field treatments (eg photodynamic therapy), radiotherapy, retinoid chemoprophylaxis with acitretin, and skin resurfacing.

If the diagnosis is uncertain, or if malignancy is suspected (eg the lesion is thick, tender or atypical, or does not respond to treatment), biopsy for histopathology is recommended.