Actinic (Solar) Keratosis Symptoms, Causes & Treatment Options

Actinic keratosis is a rough red-pink bump caused primarily by exposure to ultraviolet light. Actinic keratoses should be evaluated and treated by a dermatologist to prevent progression to squamous cell carcinoma, a dangerous skin cancer.

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  1. Overview
  2. Symptoms
  3. Potential Causes
  4. Treatment, Prevention and Relief
  5. When to Seek Further Consultation
  6. References

What Is Actinic (Solar) Keratosis?


Actinic keratosis is a precancerous skin growth that presents as single or grouped rough-textured, reddish-pink bumps on sun-exposed areas like the face and hands. Untreated actinic keratoses may progress to squamous cell carcinoma, a potentially deadly skin cancer. Actinic keratosis is caused by ultraviolet radiation from the sun or from tanning beds. A compromised immune system also increases the risk of developing actinic keratoses. Actinic keratoses can be treated by targeting individual lesions with cryosurgery, curettage, or shave excisions. Larger groups of actinic keratoses may be treated with chemical field treatments like 5-fluorouracil and others. Sun safety is the best way to prevent actinic keratoses.

Recommended care

Actinic (Solar) Keratosis Symptoms

Main symptoms

Actinic (or solar) keratosis generally presents as a gritty-textured bump or patch on the skin with a pink or red base, measuring anywhere from several millimeters to several centimeters in diameter. Actinic keratoses may occur alone, in small groups, or in large groups covering whole areas of skin. Some specific features of actinic keratosis are listed below:

  • Texture: There are many possible diagnoses for a small pink lesion on the face, but the gritty, sandpaper-like texture of an actinic keratosis is a fairly specific feature.
  • Scale: Actinic keratoses often cause flaking and scaling of the overlying skin.
  • Duration: Because of its red-pink color and rough texture, actinic keratoses may resemble scabs or abrasions; however, actinic keratoses will persist indefinitely, while scabs can be expected to improve and resolve within days to weeks.
  • Location: Because sun exposure is a causative risk factor for actinic keratoses, these lesions will often occur at sites that have received a large amount of sun exposure, like the face, neck, and backs of the hands.
  • Pain or discomfort: Some but not all actinic keratoses may hurt or itch [1].

Special presentations

The features above are present in the majority of actinic keratoses. Some less common presentations of actinic keratosis are listed below:

  • Hypertrophic actinic keratosis: These actinic keratoses will have a thicker scale and may develop the appearance of a thickened scab.
  • Pigmented actinic keratosis: Pigmented actinic keratoses may be brown, black, or blue in color and may be difficult to distinguish from a mole or a melanoma skin cancer.
  • Actinic keratosis with cutaneous horn: In this condition, an actinic keratosis may develop a cone-shaped accumulation of skin cells above its base that resembles a horn.
  • Atrophic actinic keratosis: These actinic keratoses have no overlying scale, and may just look like a smooth red or pink bump.

Actinic (Solar) Keratosis Causes

Actinic keratoses and non-melanoma skin cancers like squamous cell carcinoma and basal cell carcinoma are some of the most common malignancies in the world. Actinic keratoses occur when skin cells’ DNA has been damaged, or when the immune system has become weakened. Ultraviolet light is the main cause of actinic keratoses, as detailed below.

Ultraviolet light

UV light is the biggest cause of actinic keratoses and many other skin cancers. It damages skin cells’ DNA and weakens the immune system of the skin [2]. Some specifics are below:

  • Sunburns: Blistering or severe sunburns can greatly increase your risk of skin cancer.
  • Tanning beds: Tanning beds concentrate harmful UV radiation and should be avoided.
  • Fair pigmentation: Although individuals of all skin tones can get skin cancers and actinic keratoses, fair-skinned, fair-haired individuals are at higher risk.
  • Occupational risks: Those who work outside, those who drive for a living, and individuals in the airline industry may be at increased risk of actinic keratoses and skin cancers.

Other risk factors

These other factors may also increase the risk of actinic keratoses and skin cancers:

  • Immunosuppression: People with suppressed immune systems, from organ transplants, certain medications, and other medical conditions are at increased risk for actinic keratoses and other skin cancers.
  • Viruses: Human papillomavirus (HPV) can cause warts and certain cancers. This virus can be responsible for actinic keratoses, especially those in the genital region.
  • Chemicals and radiation: Exposure to certain industrial chemicals and radiation like X-rays may increase the likelihood of actinic keratoses [3].

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Treatment Options, Relief, and Prevention for Actinic (Solar) Keratosis

Treatments for actinic keratoses fall into two main categories: localized and field treatments. Local treatments are best when treating a limited number of actinic keratoses so that each lesion can be targeted individually by the doctor. When there are too many actinic keratoses in an area to treat individually, field treatments may be required.

Localized treatments

  • Cryosurgery: One of the best ways to treat actinic keratoses is to freeze them with a targeted spray of very cold liquid nitrogen. This can be performed in the dermatologist’s office and does not require anesthesia, cutting, or stitching.
  • Curettage (with or without electrodesiccation): Curettage is the act of scraping off actinic keratoses with a sharp, loop-shaped instrument. This procedure will be performed in the dermatologist’s office under general anesthesia. Sometimes electrodesiccation (burning the site with an electrical cautery tool) will be performed after curettage is complete.
  • Shave excision: This procedure uses a sharp blade to remove the top layer of the skin containing the actinic keratosis under local anesthesia. One advantage of this method is that it may allow for examination of the actinic keratosis under the microscope for further diagnostic workup.

Field treatments

  • 5-Fluorouracil: This topical chemotherapy cream is applied daily for about a month. It will be taken up by the actinic keratoses and will cause them to scab and fall off. The effect may be quite dramatic and may disrupt your appearance during this time. Generally, the lesions will heal without scarring after the treatment is complete.
  • Imiquimod (Aldara): Imiquimod is a topical medication that causes the immune system to react strongly against actinic keratoses, potentially eliminating them over a 6-week treatment course.
  • Diclofenac (Solaraze, Voltaren): This topical non-steroidal anti-inflammatory drug (the same class as ibuprofen, aka Advil or Motrin) can be effective in treating actinic keratoses. This drug has a lower side effect profile than the above treatments but requires a much longer 90-day treatment course.
  • Ingenol mebutate (Picato) gel: This agent treats actinic keratosis by killing fast-growing skin cells. Its effects are similar to the agents listed above [4].


The most important way to avoid actinic keratoses and other skin cancers is to practice sun safety, as detailed below:

  • Stay out of the sun: Sun damage is cumulative, so the less time you spend in direct sunlight, the better.
  • UV protection: Use a sunscreen rated SPF 30 or higher and reapply as directed, especially if sweating or swimming. Zinc or mineral sunscreens offer superior protection. UV resistant clothing is perfect for avoiding greasy lotions as well.
  • Avoid peak hours: Peak hours are between 10 am and 2 pm. Remember that UV light is present on cloudy days as well.

In addition, there is some evidence that taking 500 mg of nicotinamide (Vitamin B3) twice daily may reduce the number and severity of actinic keratoses [1].

When to Seek Further Consultation for Actinic (Solar) Keratosis

The number one reason to seek treatment for actinic keratoses is that they can progress into squamous cell carcinoma (SCC), a skin cancer that can be disfiguring and even deadly. Even when treatable, SCC can require extensive surgical treatments that may be difficult, time-consuming and costly. Various estimates place the risk of actinic keratosis progressing to SCC from 0.1% per lesion per year, to 10% over 10 years.

It is also essential to seek consultation with a dermatologist because many other dangerous (and less dangerous) skin conditions can masquerade as actinic keratoses, including squamous cell carcinoma (SCC), basal cell carcinoma (BCC), seborrheic keratosis, warts, and certain types of melanoma. Only a dermatologist can say with certainty which lesion you actually have and how to treat it effectively.

Finally, certain features may indicate that an actinic keratosis is progressing to the more dangerous squamous cell carcinoma. If you notice any of the following features, seek consultation with a dermatologist for definitive diagnosis and management immediately:

  • Pain or tenderness
  • Increased volume or thickness
  • Increased inflammation: including redness, bleeding, or irritation
  • Failure to respond to first-line therapies