Actinic Keratosis ICD-10: L57.0

Precancerous skin lesion / Sun-damaged skin

Often searched as: rough scaly patch on face, crusty spot on forehead, scaly skin from sun damage, rough patch on scalp, dry rough spot on ear, skin that feels like sandpaper, pre-skin cancer treatment, precancerous skin spot…

Clinical urgency level

lowmediumhigh

Systems Affected

skin (epidermis)

Severity Levels

mild

One or few AKs on a low-risk site, thin and flat — responds well to cryotherapy or topical treatment (imiquimod, 5-FU).

moderate

Multiple AKs across large sun-damaged areas (field cancerization), some hypertrophic — requires field treatment (photodynamic therapy, topical 5-FU or imiquimod over a larger area).

severe

Hypertrophic or hyperkeratotic AK, or AK suspected of progressing to invasive SCC (thickening, ulceration, bleeding) — requires biopsy and possible excision.

Red Flags

  • An AK that becomes thickened, raised, or nodular (possible SCC transformation)
  • Bleeding or ulceration of a previously flat scaly patch
  • Rapid increase in size over weeks
  • Pain or tenderness developing in a previously asymptomatic lesion
  • Multiple new AKs appearing rapidly in an immunocompromised patient
  • Any AK on the lip (actinic cheilitis) — higher SCC transformation risk

Clinical Presentation

Actinic keratosis — rough, scaly erythematous patch on the forehead

Actinic keratosis — rough, scaly erythematous patch on the forehead

Source: Wikimedia Commons (CC BY-SA 3.0 )

Actinic keratosis image gallery — DermNet NZ

View gallery on DermNet NZ (image gallery reference)

When to See a Doctor

See a dermatologist if you have rough, scaly patches on sun-exposed skin — especially the face, scalp, ears, or backs of hands — that have been present for months without going away. AKs are treatable precancers; early treatment prevents SCC. Don't ignore a crusty, scaly spot just because it doesn't hurt.

Differential Diagnosis

  • Squamous cell carcinoma in situ / Bowen's disease (well-defined, larger — biopsy needed)
  • Seborrheic keratosis (waxy, stuck-on — benign)
  • Psoriasis (well-defined silvery plaques)
  • Discoid lupus erythematosus (scarring, depigmented center)
  • Wart (verruca — viral, rougher texture)
  • Superficial basal cell carcinoma (may mimic — biopsy key)

Comorbidities

  • Squamous cell carcinoma (AK is the direct precursor lesion)
  • Basal cell carcinoma (co-existing UV damage)
  • Field cancerization (widespread UV-damaged skin with multiple AKs)
  • Immunosuppression (organ transplant — AKs are numerous, aggressive, higher SCC risk)
  • Xeroderma pigmentosum
  • Albinism

Prognosis

Individual AKs have a low annual transformation rate to SCC (~0.1–1%), but the cumulative risk with many lesions over decades is meaningful. Approximately 60% of SCCs arise from AKs. Treated AKs have excellent outcomes — cryotherapy, photodynamic therapy, topical 5-FU, and imiquimod all achieve high clearance rates. However, new AKs continue to form on UV-damaged skin, making ongoing surveillance essential. Strict photoprotection is the most important long-term strategy.

Detailed Overview

Causes, Symptoms, and When to Take Action Actinic keratosis (AK) is a precancerous skin lesion caused by long-term exposure to ultraviolet (UV) radiation. Although AK itself is not cancer, it has the potential to develop into squamous cell carcinoma (SCC) if left untreated. How It Looks Texture: Rough, dry, or scaly patches Color: Pink, red, flesh-toned, or brownish Shape: Flat or slightly raised with irregular borders Location: Commonly appears on sun-exposed areas — face, ears, scalp, neck, forearms, and backs of the hands Why Does It Appear? Mainly caused by chronic UV exposure. Contributing factors include fair skin type, older age, outdoor occupations, history of sunburns, and immunosuppression. Should You Be Concerned? Yes — a small percentage of AKs can evolve into invasive SCC. Warning signs include rapid growth, bleeding, ulceration, thickening, or sudden pain. Can You Prevent It? Use daily broad-spectrum sunscreen (SPF 30+), avoid peak UV hours, wear protective clothing, avoid tanning beds, and perform regular skin checks. 👉 How Piel AI Can Help Piel AI allows you to monitor skin changes over time with photo tracking to support early detection and timely consultation. Summary Actinic keratosis is a precancerous lesion linked to chronic UV exposure. Common in older, fair-skinned individuals with high sun exposure. May progress to squamous cell carcinoma if left untreated. Sun protection and early intervention are essential.

Tags

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