Causes and Risk Factors
Actinic keratoses are the direct result of cumulative UV damage to the outer layer of skin. They are most likely in people with:- Years of sun exposure: Outdoor work, boating, golf, and everyday errands in a sunny climate all contribute; tanning beds add further damage.
- Fair skin that burns easily: Light skin, blond or red hair, and blue or green eyes carry the highest risk.
- Older age: AKs typically appear after 40 and become very common in later decades as damage accumulates.
- A weakened immune system: Transplant medications and some blood disorders let sun-damaged cells grow unchecked, increasing both AKs and skin cancers.
Symptoms
AKs favor the sun-exposed areas: the face, ears, scalp (especially with thinning hair), forearms, and backs of the hands. Typical features include:- A rough, sandpaper-like patch: Often easier to feel than to see, usually less than a quarter-inch across.
- Pink, red, or brown color with dry scale: The scale may flake off and re-form repeatedly in the same spot.
- Itching, burning, or tenderness: Some AKs are irritated by sun, sweat, or shaving.
- A persistent or thickening spot: Unlike patches of dermatitis or facial redness from rosacea, an AK stays fixed in one place and does not clear with moisturizers.
- Lip involvement (actinic cheilitis): Persistent dryness, scaling, and blurring of the lower lip border is a related form of sun damage that deserves evaluation.
Diagnosis
Clinicians usually recognize actinic keratoses by their look and feel during a skin examination. A spot that is unusually thick, tender, growing, or bleeding may be biopsied to make sure it has not already become a squamous cell carcinoma. Because sun damage affects whole regions of skin rather than single spots, the examination usually covers the entire face, scalp, ears, arms, and hands to find additional lesions.Treatment
Treatment removes damaged cells before they can progress. Options depend on how many spots are present:- Cryotherapy: Freezing individual spots with liquid nitrogen is quick and effective; the spot scabs and falls away over a week or two.
- Field treatments: Prescription creams such as 5-fluorouracil or imiquimod treat whole areas of sun damage, clearing visible and invisible AKs together.
- Photodynamic therapy: A light-activated medication destroys precancerous cells across a broad area, useful for the scalp and face.
- Ongoing prevention: Daily sunscreen, hats, and sun-protective clothing prevent new AKs and lower future skin cancer risk.
Complications
The main concern is progression to squamous cell carcinoma. Warning signs that an AK may be transforming include rapid growth, thickening, pain, ulceration, or bleeding — changes like these should be evaluated promptly rather than watched. Once you have had one actinic keratosis, more are likely, so periodic skin checks become part of good preventive care. Zimmer Medical Group's St. Petersburg primary care team can examine suspicious rough spots, treat or refer as needed, and build skin surveillance into your annual visit — schedule an appointment to have your skin checked.Treating Sun-Damaged Skin in a Florida Climate
Treating actinic keratoses is less about any one spot than the region of skin around it. What follows is what each treatment involves, how healing looks, and how to stop the next crop.
What cryotherapy involves
Freezing with liquid nitrogen stings for seconds and needs no anesthetic. The spot reddens, sometimes blisters within a day, crusts, and the scab separates in one to three weeks, leaving pink skin that fades. Healing is slower on the legs and in older skin. A small pale mark is common and permanent in some people, which matters on the face. Cryotherapy suits a handful of discrete spots; a lesion that returns in the same place within weeks should be re-examined rather than frozen again, because a thick or recurring lesion can be an early squamous cell cancer.
Field treatment looks worse before it looks better
When a whole area is sun-damaged, creams are applied to the region rather than to visible spots: they clear lesions too early to see. Fluorouracil cream is used for a set number of weeks and predictably produces redness, crusting, weeping, and soreness that peak partway through and settle within weeks of stopping. That reaction is the treatment working, not an allergy. Imiquimod works similarly through the immune system and can cause flu-like days. Photodynamic therapy treats a broad area in the office and requires strict avoidance of sun and bright light for about two days afterward. Plan these around travel, and keep cream away from the eyes, nostrils, and lips.
The routine that prevents the next crop
Daily broad-spectrum sunscreen of SPF 30 or higher, reapplied every two hours outdoors, reduces new keratoses. Sun-protective clothing beats any cream, and a wide-brimmed hat covers the scalp and ear tops people miss most. Window glass blocks burning rays but not aging ones, so the left forearm and cheek take steady damage during Florida driving; water, sand, and concrete reflect light upward. See our sun safety, eye and skin protection, and sunburn versus sun poisoning guides. Oral nicotinamide has been studied as an add-on for people who keep forming lesions; ask before starting.
Skin that needs a schedule rather than a reaction
Transplant and immune-suppressing medications make keratoses form faster and turn cancerous more often, so those patients need a set skin-check interval, not an as-needed visit. The same applies after a first squamous or basal cell skin cancer or a melanoma. Our skin cancer screening article explains what a full-body check covers.
What is mistaken for an actinic keratosis
Waxy, stuck-on brown growths are harmless seborrheic keratoses; see our benign skin growths after 50 article. Persistent facial redness with visible vessels is usually rosacea, covered in our rosacea and sun triggers guide; scaly plaques that come and go with moisturizer suggest dermatitis or psoriasis. A spot that thickens, becomes tender, ulcerates, or bleeds needs a biopsy. Our dermatologic team examines rough spots. MedlinePlus and the CDC publish patient guidance on actinic keratosis and sun protection.
If a rough patch has outlasted a month of moisturizer, schedule a visit.