Actinic Keratosis
An actinic keratosis is a rough, scaly patch caused by years of sun. It is a precancer, meaning it is the step before skin cancer rather than cancer itself. Most never progress, but most squamous cell carcinomas start as one, which is why they are treated.
Key facts
Actinic Keratosis at a glance.
Typical signs
Rough, scaly sun-damaged patches
Common locations
Face, ears, scalp, hands
Expected course
May persist, recur or progress
Treatment options
Freezing, field creams or light treatment
What is it?
Top things to know about Actinic Keratosis
- It is ultraviolet damage. Actinic keratoses are rough, scaly areas caused by UV damage to skin cells.
- It appears on sun-exposed skin. They occur most often on repeatedly exposed areas.
- It is precancerous. Some can progress to squamous cell carcinoma.
- Some lesions need a biopsy. Thick, painful, ulcerated or enlarging spots are checked for invasive cancer.
What it looks like
What Actinic Keratosis looks like
Actinic keratoses are rough, scaly spots caused by years of sun damage. They are often easier to feel than see, like a patch of sandpaper. They can be skin-colored, pink, red or brown and usually measure a few millimeters to a centimeter. They appear on sun-exposed areas such as the face, ears, scalp, lips, forearms and backs of the hands. A small number can turn into squamous cell carcinoma.
Actinic keratoses come in several forms.
Classic actinic keratosis
Rough pink or red scaly spot.
Hypertrophic actinic keratosis
Thick, raised and crusted.
Actinic cheilitis
Rough, dry patches on the lower lip.
Pigmented actinic keratosis
Brown and flat.
Where it shows up
Common sites include the face, ears, scalp, hands and forearms. The shaded sites are examples rather than a complete distribution.
Face
Facial locations.
Scalp and behind the ears
Locations on the back of the head.
Arms
Locations along the forearms.
Hands and wrists
Hand, finger or wrist locations.
On different skin tones
Actinic Keratosis on different skin tones
Actinic keratoses are most common in lighter skin that burns easily, where they look pink or red. They are much less common in brown and Black skin, and when they do appear, they are often brown or skin-colored rather than red. Sun protection lowers the risk on every skin tone.
What happens in Actinic Keratosis?
Repeated ultraviolet exposure damages the DNA of surface skin cells, allowing abnormal cells to grow within the epidermis. A rough, scaly patch develops, and some lesions can progress to skin cancer.
- A rough patch forms: Some lesions can progress to skin cancer.
- Abnormal cells multiply locally: The changes remain within the epidermis.
- UV damage accumulates: Repeated sun exposure alters skin-cell DNA.
Causes and triggers
What causes Actinic Keratosis
Causes
Why it happens
Actinic keratoses are caused by years of ultraviolet light damaging skin cells. They are a warning sign of sun damage.
Fair skin that burns easily is inherited and is the biggest risk.
Risk factors
Raise the odds
- Fair skin
- Age over 40
- Weakened immunity
- Outdoor work
Triggers
Bring it on or make it worse
- Unprotected sun exposure (Well established)
- Tanning beds (Well established)
- Sunburns (Strong link)
When it usually starts
When it usually starts
Actinic Keratosis
Usually develops in adults after years of ultraviolet exposure, especially with fair or immunosuppressed skin.
Daily care
Daily care for Actinic Keratosis
Daily broad-spectrum sunscreen
SPF 30 or higher on face, ears, neck, scalp and hands.
A wide-brimmed hat and sleeves
More reliable than sunscreen, no reapplying.
Lip balm with SPF
Higher-risk site, and almost nobody protects it.
Tirbanibulin ointment
A short course, milder reaction, useful on face and scalp.
Photodynamic therapy
A whole area in one or two visits, sore and red for days.
Nicotinamide
500 mg twice a day modestly reduces new patches in high-risk people.
Discuss closer monitoring if your immune system is suppressed
Far more patches, and much more progression.
Follow the prescribed course and ask about severe or unexpected reactions
Some prescribed treatments cause expected inflammation, but marked pain, blistering or an unexpected reaction needs advice; do not force completion through severe injury.
Ask about sun precautions for photosensitizing medicines; do not stop them yourself
Make a given amount of sun do more damage.
Avoid: Continuing unprotected sun exposure
Cumulative, and the biggest item here.
Avoid: Skipping sunscreen on scalp and lips
Exactly the sites people forget.
Avoid: Tanning beds
The same damage, concentrated.
Avoid: Picking or filing off the scale
It returns, because the problem is beneath it.
Avoid: Ignoring a patch that has changed
Thickening, tenderness or bleeding means biopsy.
Avoid: Smoking
Linked to lip damage and poorer healing.
Avoid: Treating them as dry skin
Moisturizer softens the scale and leaves the cells alone.
Avoid: Treating only the spots you see
New patches keep arriving from the skin around them.
Avoid: Skipping follow-up skin checks
Progression is found by looking.
Treatments
Treatments for Actinic Keratosis
Nicotinamide 500 mg twice a day
An over-the-counter form of vitamin B3, taken as a tablet, which modestly reduced new actinic keratoses and new skin cancers in people at high risk. The effect is real but small, and it stops when the tablets stop. It is an add-on to sun protection and treatment, not a replacement for either. Check with your doctor before starting it.
Lip balm with SPF
The lower lip is the site almost nobody protects and one of the higher-risk places for a patch to progress. A balm with SPF 30 or higher, reapplied through the day, is the practical way to cover it. It will not treat a lip that is already persistently dry, scaly or cracked — that needs looking at.
Fluorouracil
Fluorouracil cream (5-FU). The best-studied cream for treating a whole sun-damaged area rather than single spots, usually applied for two to four weeks. It attacks abnormal cells wherever they are, so it also clears patches that had not surfaced yet. The area becomes red, crusted and sore where those cells were, often revealing more than you knew you had — that reaction is the treatment working, and stopping early leaves the area half treated. If you are pregnant or breastfeeding, ask the doctor managing your pregnancy first.
Imiquimod
Imiquimod cream. Prompts your own immune system to clear the abnormal cells, applied a few times a week over a longer course than fluorouracil. It also treats the whole field, and it can suit the face and scalp well. Expect redness and crusting, and sometimes a few days of feeling fluey. The same pregnancy advice applies: ask the doctor managing your pregnancy first.
Tirbanibulin
Tirbanibulin ointment. A newer ointment used once a day for five days on the face or scalp. The short course and the milder reaction are the point of it — most people are through the redness and flaking within a couple of weeks. It is used on a limited area at a time, and long-term results are less well known than for fluorouracil.
Diclofenac gel 3%
An anti-inflammatory gel applied twice a day for two to three months. It is much gentler than fluorouracil, which makes it an option for people who cannot manage a strong reaction on visible skin. It clears fewer patches, and the course is long.
Tretinoin
A prescription retinoid people often ask about here, because it is known for sun-damaged skin. It smooths texture and helps the mottled color, but trials have not shown that it clears actinic keratoses or prevents skin cancer. It is reasonable for the look of sun damage, and it is not a treatment for the patches themselves.
Acitretin
An oral retinoid used mainly for organ transplant recipients and others whose immune systems are suppressed, who make large numbers of these patches and progress from them more often. It reduces how many new patches and skin cancers appear while it is taken, and the benefit fades once it is stopped. It has real side effects and needs blood tests. It must never be taken in pregnancy, and pregnancy has to be avoided for three years afterwards.
Cryotherapy
Freezing with liquid nitrogen is the quickest option for a handful of separate patches, done in a few seconds each with no prescription. It stings sharply, then blisters or crusts and heals over one to three weeks. Its limit is that it only treats what can be seen, so new patches keep arriving from the damaged skin around them. It often leaves a permanently pale mark, which is more noticeable on deeper skin tones — worth asking about before you start.
Photodynamic Therapy
A light-activated liquid is put on the whole area, left to soak in, then activated with a lamp. It treats a broad field in one or two clinic visits instead of weeks of cream, which suits people who cannot manage a long course at home. The area stings during treatment and is red, swollen and sore for several days, and the treated skin has to be kept out of light straight afterwards.
Electrodesiccation and Curettage
The thicker, harder patches that freezing struggles with are scraped away under local anesthetic and the base sealed. It is useful when a patch has built up into a lump or a horn, and the scraped material can be sent for testing. It leaves a small scar, and like freezing it treats only the spot in front of you.
Chemical Peel
A medium-depth peel takes off the damaged top layer across a whole face or scalp at once, so it treats the field rather than single spots. It is an option when creams have not been tolerated. The skin is red and peeling for about a week, and results depend a lot on who is doing it and at what strength.
Skin Biopsy
Not a treatment, but the right answer for a patch that is thick, firm, tender, bleeding, growing quickly, bigger than about a centimeter, forming a horn, sitting on the lip or ear, or unchanged after proper treatment. A few minutes under local anesthetic tells you whether the abnormal cells are still confined to the top layer or have gone deeper. Freezing a patch like that instead removes the evidence without answering the question.
Outlook
What to expect with Actinic Keratosis
Actinic keratoses are not steady. Individual spots come and go, which is one reason they get dismissed. The trend over years is upward.
- 1
Weeks to months · Appearing
A small area turns rough and gritty, usually noticed by touch while washing or shaving before it is visible.
- 2
Ongoing · Coming and going
Many flake off, look resolved for a few weeks, then return in the same place. Some do clear on their own, particularly with less sun.
- 3
Over years · Accumulating
Someone who once had two may have twenty-five a decade later. The skin between them develops the same mottled color, fine broken vessels and thin crepe-like texture.
- 4
Warning change · Something is different
A patch thickens, turns tender, itches persistently, bleeds, forms a hard horn, grows quickly or reaches more than about a centimeter. Those changes suggest it has progressed. In squamous cell carcinoma the cells fill the top layer and then break through into deeper skin, which takes years, and much less in anyone immune-suppressed.
- 5
After treatment · What follows
Treated spots heal within a few weeks. New ones are expected, because the damage remains. Most people settle into periodic checks and occasional retreatment rather than a one-time fix.
Complications
Complications to know about
Squamous Cell Carcinoma
The skin cancer that these patches can turn into. Any one patch is unlikely to progress in any one year, but most squamous cell carcinomas begin in an actinic keratosis or in the damaged skin around one, and people usually have many patches over many years. Treating patches lowers how many of these appear later. A patch that thickens, hurts, itches, bleeds or grows quickly is sampled rather than frozen.
Actinic cheilitis on the lip
The same sun damage on the lower lip, where it shows up as persistent dryness, scaling, cracking or a lip border that has blurred into the skin. It is easy to read as chapped lips, and lip balm does not fix it. The lip matters more than its appearance suggests, because it is a higher-risk site if a patch progresses, so a dry scaly lower lip that has not settled in a month should be looked at.
When to get help
When to get help
When to seek care
Arrange assessment of persistent rough spots. Rapid growth, tenderness, thickening, ulceration or bleeding raises concern for skin cancer.
Lookalikes
What else could it be?
Seborrheic Keratosis
Seborrheic keratosis often looks raised, waxy and stuck on. Actinic keratosis is usually flatter and feels gritty, like sandpaper.
Basal Cell Carcinoma
Basal cell cancer may slowly enlarge and repeatedly bleed or scab. Actinic keratosis more often flakes off and returns in the same spot.
Warts
Warts usually stand up from the skin and may have tiny dark dots. Actinic keratoses are often flatter, gritty patches on sun-damaged skin.
Questions
Questions you might be asking.
Is an actinic keratosis cancer?
No. It is a precancer - abnormal cells in the top layer of skin that have not formed a tumor. A minority become squamous cell carcinoma, and they are treated because most squamous cell carcinomas begin this way.
What are the chances mine turns into cancer?
Low, for any single patch in any single year. Published estimates vary too widely to quote. What matters is cumulative: more patches, for longer, with more sun. A suppressed immune system raises it considerably.
Does freezing hurt, and what will it look like afterward?
It stings for a few seconds and aches afterward. It blisters or crusts within a day or two and heals over one to three weeks. A pale mark often remains where the skin regrows with less pigment - sometimes permanent, and more noticeable on deeper skin tones.
Why does the cream make my skin look so much worse?
That is how it works. Fluorouracil and imiquimod provoke a reaction exactly where abnormal cells are, so the area turns red, crusted and sore, often revealing more patches than you knew you had. It settles a couple of weeks after finishing. Stopping early leaves the area partly treated.
Will they come back?
New ones almost certainly will, because the sun damage remains. That is not treatment failure. Most people settle into periodic checks, occasional retreatment and daily sun protection - the protection is what reduces how many new ones appear.
Should I treat the spots or the whole area?
A few discrete patches, and freezing is efficient. Many patches, or a whole area of damaged skin, and a cream or photodynamic therapy lasts longer, because it reaches cells that have not surfaced yet. Downtime is part of the choice.
Sources
Sources and further reading
Related
Keep exploring.
Photodynamic Therapy
Cryotherapy
Basal Cell Carcinoma
Seborrheic Keratosis
Warts
Electrodesiccation and Curettage
Chemical Peel
Tretinoin
Skin Biopsy
Actinic Keratosis vs Seborrheic Keratosis
Actinic Keratosis vs Warts
