FFinalistSouthampton · 2027
Dermatology
AKT · Dermatology/Malignant & pre-malignant

Actinic keratosis

Pre-malignant keratinocyte dysplasia (chronic UV)

Overview

A pre-malignant patch of keratinocyte dysplasia from cumulative sun damage. Rough, scaly macules/papules on chronically sun-exposed skin — often better felt than seen (sandpaper texture). A small proportion progress to invasive SCC, so thick/changing lesions are treated and reviewed.

Recognise

  • Rough, scaly, erythematous or skin-coloured macules/papules — often felt as sandpaper before clearly seen
  • Sun-exposed sites: bald scalp, face, ears, dorsal hands, forearms; usually multiple ("field change")
  • A thick, tender, or rapidly growing lesion (or a cutaneous horn) raises suspicion of SCC

Red flags

  • Induration, tenderness, ulceration or rapid growth in an actinic keratosis → exclude invasive SCC (biopsy)

Differentials & how to tell them apart

Squamous cell carcinomaan indurated, tender, growing nodule — AK is a thin rough macule; biopsy if in doubt
Bowen diseasea larger well-defined scaly in-situ plaque (full-thickness dysplasia) vs the smaller rough AK
Seborrhoeic keratosis"stuck-on" warty pigmented plaque, benign, not sun-damage dysplasia
Discoid eczema/psoriasisinflammatory, responds to topical steroid

Clinical image

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Actinic keratosis — clinical imagesDermNet

Investigations

Clinical/dermoscopy; biopsy any lesion that is thickened, tender, or growing to exclude SCC. Assess for field change and other skin cancers.

Management

Sun protection ± cryotherapy (discrete lesions) or topical field therapy (5-FU/imiquimod) for multiple

  1. 1Sun protection and emollients for all; thin/few AKs may be observed or treated with cryotherapy.Gate: A thickened, tender, indurated or rapidly growing "actinic keratosis" may already be an invasive SCC → biopsy rather than just freezing it
  2. 2Multiple/field-change AKs → topical 5-FU, imiquimod or diclofenac, or photodynamic therapy; ongoing sun protection and skin-cancer surveillance.
Sun protection + emollient — foundation for all; some thin AKs regress
Cryotherapy — for discrete lesions
Topical 5-fluorouracil, imiquimod, or diclofenac gel — field treatment of multiple AKs
Photodynamic therapy — extensive field change

Key points

AK is a marker of significant sun damage and overall skin-cancer risk — treat the field and survey the patient, not just the single spot. A cutaneous horn may overlie an SCC.

Monitor & prognosis

Field response and surveillance for SCC/other skin cancers.

Most do not progress; field therapy reduces the SCC risk.

Source: NICE CKS Actinic keratosis; BAD guideline