Actinic keratosis (AK), also called solar keratosis, is a type of premalignant lesion that looks like a thick and rough patch on the skin. It often develops in areas that have been excessively exposed to the sun.
“Actinic keratoses (AKs) are common cutaneous lesions associated with chronic exposure to ultraviolet (UV) radiation. AK presents scaly, erythematous papule or plaque and is considered the earliest clinically recognizable manifestation of squamous cell carcinoma (SCC) that is capable of transforming into squamous cell carcinoma in situ and invasive squamous cell carcinoma. Fair skin, cumulative sun exposure, immunosuppression, and age increase the risk of AK. AK is the second most common diagnosis seen by dermatologists in the United States, with the direct cost of therapy estimated at more than $1 billion per year with indirect costs nearing $300 million. The prevalence of AK was reported at 11 to 25 percent in 2008 with 5.2 million patient visits occurring annually for AK during the period 2000 through 2003.”1
The development of actinic keratosis is slow and progressive and takes years to manifest itself. Because of this, they are usually detected more frequently in people over 41 years of age. Hence, it’s important to attend to any warning signals in a timely fashion to achieve an effective treatment.
“It is most frequently seen in the areas which are mostly affected by DNA damage caused by UV radiation including the head, face, ears, lower lip, dorsal region of hands, lower legs, décolleté region, neck and upper back. AK is the most widely seen skin cancer on a sun-damaged skin. It appears as squamous, skin-colored, pink or red-brown papules, macules or plaques with vague margins. It can be a single lesion, but more commonly there are multiple lesions on a photodamaged skin. A classical aspect of AK is the rough surfaces of lesions feeling like sandpaper. The size of lesions can range from a few millimeters to 3-4 cm and larger. When the lower lip is affected, it appears as a dry, scaled and atrophic lesion, which is called actinic cheilitis. Depending on its clinical appearance, AK may be of classical, hypertrophic, atrophic or pigmented type, or appear as cornu cutaneum or actinic cheilitis. The severity of AK was divided into 3 phases within itself: (1) Lesions not so visible, vaguely felt with palpation; (2) Lesions are of medium thickness, easily palpated and seen; and (3) Hyperkeratotic and thick lesions.”2
People with certain physical traits are more likely to develop one or more lesions of actinic keratosis. The physical attributes that are associated with actinic keratosis the most is hair color (redheads and blondes are more likely to develop it) and eye color (blue and green). Also, the risk increases significantly by spending an excessive amount of time outdoors or living in sunny places.
Approximately 22% of actinic keratosis cases can progress into skin cancer (squamous cell carcinoma). However, if it’s treated on time it can be successfully eliminated before it develops into an uncontrollable disease.
Actinic keratosis is caused by the deterioration of the skin due to frequent exposure to UV rays from the sun or tanning booths. Sun damage accumulates over the years, even when said exposure is brief.
The risk rises among those who do not use sunscreen or preventive measures to minimize the impact of the sun’s ultraviolet A (UVA) and ultraviolet B (UVB) rays. In fact, even cloudy days are not full-proof, since up to 70% of the sun’s rays can penetrate the clouds and make their way to the earth’s surface.
A smaller percentage of actinic keratosis may be related to prolonged exposure to X-rays or to various industrial chemical agents. Anyone can develop actinic keratosis. However, there are some factors that increase the chances of suffering from it:
– Age (over 40 years old)
– Residing in sunny places like beaches, which can bring about excessive exposure to sunrays.
– Having a heavy history of being sunburnt
– Physical attributes such as freckles, blond or red hair and green or blue eyes.
– A family history of actinic keratosis or skin cancer
– Suffering from a weakened immune system due to chemotherapy, leukemia or other autoimmune diseases.
– Having previously had an organ transplant.
“Risk factors for the development of actinic keratosis include, fair skin or light pigmentation status, caucasian individuals, freckles, light colored eyes (blue or green), blonde or red hair, male gender, older age, severe baldness, skin wrinkling and increased sun exposure due to outdoor occupation/activity. Actinic keratosis presents as a rough, itchy and scaly lesion that can occur singly but usually grows as multiple dry, fleshy colored, erythematous papules or plaques with telangiectasia, that are usually covered in brown or yellow adherent scales. The distribution of actinic keratosis depends on a number of factors such as ethnicity, socioeconomic status, age, skin type, occupation, sex, and birth place.”3
“AKs typically present as red, scaly lesions on visible, sun exposed skin areas, such as face scalp and dorsal hands, thus often causing cosmetic discomfort. In addition, AK lesions may itch, bleed, and adhere to clothing and due to its pre-malignant nature patients may fear the risk of developing skin cancer. The presence of AK-lesions may thus influence affected persons’ well-being because of cosmetic reasons, locally hampering symptoms, and also due to fear of developing skin cancer. Studies including patient reported outcome measures and health related quality of life (HRQoL) is increasingly used in clinical practice and in clinical trials in dermatology. Information about HRQoL is requested both by clinicians and reimbursement agencies. Information is limited on the potential impact of AKs, its accompanying symptoms and treatments, on patients’ HRQoL.”4
Actinic keratosis appears as a scale-like growth in the form of a scab, which appears in areas exposed to the sun such as the forearms, neck, face, ears, hands and shoulders. The first manifestations are so slight that they can be recognized more by touch than by sight. The sensation when touching them tends to be similar to that of passing a finger across sandpaper.
As the problem progresses, the signs and symptoms become more evident. Affected patients can develop:
– Thick, dry, rough and patchy skin that can measure less than an inch in diameter, similar to a wart
– Reddish, brown or pink colors on the skin
– Itching and burning sensations in the affected area
The lack of an appropriate treatment can lead to the formation of a squamous cell carcinoma, which is a type of cancer that can be treated if an opportune diagnosis is achieved.
To determine if an individual has actinic keratosis, the doctor performs a thorough skin examination. If for any reason there is suspicion of cancer, you can be given suggested additional tests such as a skin biopsy.
“Actinic keratoses may be treated for cosmetic reasons or for relief of associated symptoms, but the most compelling reason for treatment is to prevent squamous cell carcinomas. Treatment options include ablative (destructive) therapies or topical therapies in patients with multiple lesions.”5
“Treatment of AK needs to be discussed with patients for several reasons. Patients should realize that there is a low rate of transformation of AK to SCC. Despite this, the presence of AK indicates that they have a higher risk for skin cancers compared to the general population, and would therefore need to be screened and checked on a regular basis. Ultimately, most patients want their AK treated, either for their malignant potential, or other reasons such as cosmesis and symptomatic relief. The discussion should also include advice on reducing or preventing further sun damage by ensuring appropriate outdoor clothing and the use of sunscreens. It has been shown that regular use of sunscreen not only prevents the development of AK, but also hastens the remission of existing AK.”6
- Many cases of actinic keratosis disappear on their own within time. However, some may return after new and extended solar exposure. Considering that some cases of actinic keratosis can turn into cancer, it’s recommended that it be removed as a precaution.
- Some procedures that your doctor might suggest are:
- Curettage and electrodesiccation (scraping of the lesion followed by the use of electricity to destroy any remaining cells)
- Excision (removal of the abnormal growth and then suturing the skin)
- Cryotherapy, which freezes and destroys cells. “Technical modalities have been divided into three main groups which include contact, spray, and intralesional types. The frequency of these methods, which are written in an order, extends to benign and malignant lesions. Contact method is applied using a cotton applicator that is usually used for common warts. The most widely used technique in dermatology clinic is the spray form directed from a 90° angle at a distance of 1–2 cm. The newly developed one is the intralesional technique mainly used in malignant lesions and keloid scars. Intralesional cryotherapy is the preferred choice than other methods due to preserving epidermis and absence of hypopigmentation and scarring. Local anesthesia is usually not necessary but may be recommended if large areas are being treated.
Cryotherapy and cryosurgery are the modalities used interchangeably. If we enlighten the terminology, cryotherapy accurately freezes the lesion, but when combined with curettage, it gets its name as cryosurgery. Nevertheless, most clinicians unintentionally confuse each other.”7
- Photodynamic therapy, which uses drugs called ‘photosensitizers’ along with a specific light wavelength to kill off potentially malignant cells.
- Medications like fluorouracil cream, imiquimod cream, ingenol mebutate gel, or diclofenac gel.
Prevention is the best tool to avoid and stop the development of actinic keratosis. Luckily, everyone is capable of incorporating some care into their daily routine. Some prophylactic tips to keep in mind are:
– Avoid exposure to the sun between 11 in the morning and 3 in the afternoon. “The role of ultraviolet (UV) radiation in skin aging is well established and the term photoaging has been coined to emphasize this cause and effect relationship. In fact, numerous studies have been conducted during the last few decades to analyze the underlying mechanisms, and based on this knowledge, developed strategies to prevent or at least delay photoaging of human skin. In this regard, UV radiation may be considered as one of the best studied environmental factors contributing to the exposome of skin aging.”8
– Use hats, sunglasses and protective clothing before going out in the sun.
– Use a broad-spectrum sunscreen (UVA / UVB) with an SPF greater than 30 that is water resistant. Apply it when going outside, even if it’s cloudy. “Composition and mechanism of action of sunscreening agents vary from exerting their action through blocking, reflecting, and scattering sunlight. Chemical sunscreens absorb high-energy UV rays, and physical blockers reflect or scatter light. Multiple organic compounds are usually incorporated into chemical sunscreening agents to achieve protection against a range of the UV spectrum. Inorganic particulates may scatter the microparticles in the upper layers of skin, thereby increasing the optical pathway of photons, leading to absorption of more photons and enhancing the sun protection factor (SPF), resulting in high efficiency of the compound.
Researchers are postulating that the generation of sunlight-induced free radicals causes changes in skin; use of sunscreens reduces these free radicals on the skin, suggesting the antioxidant property. Broad-spectrum agents have been found to prevent UVA radiation-induced gene expression in vitro in reconstructed skin and in human skin in vivo.”9
– Avoid the use of tanning chambers
“Actinic keratosis is common amongst fair-skinned patients exposed to significant amounts of UV irradiation. Although the chance of individual AK transforming to squamous cell carcinoma (SCC) is not high, they are useful markers for sun damage and skin cancer risk assessment. There is increasing interest in combining therapies for the treatment of AK, especially as the treatment options are ever increasing. However, the ultimate treatment choice will rest not only on efficacy, but also associated adverse reactions, cosmetic outcomes, accessibility, costs, compliance, and patient choice. The management of multiple AKs is a long-term prospect, with no clear cure. The best approach is the sequential treatment with a lesion-directed and a field-directed therapy. Combination therapies work well and should be adjusted according to patient requirements.”10
(1) Goldenberg, G., & Perl, M. (2014). Actinic keratosis: update on field therapy. The Journal of clinical and aesthetic dermatology, 7(10), 28. Available online at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4217291/
(2) Emre, S. (2016). Actinic keratosis and field cancerization. World Journal of Dermatology, 5(2), 115-124. Available online at https://www.wjgnet.com/2218-6190/full/v5/i2/115.htm
(3) Lalji, A. K. N., & Lalji, M. (2014). Actinic keratosis and Squamous Cell Carcinoma. Clin Res Dermatol Open, 1(1), 1-3. Available online at https://symbiosisonlinepublishing.com/dermatology/dermatology02.pdf
(4) Tennvall, G. R., Norlin, J. M., Malmberg, I., Erlendsson, A. M., & Hædersdal, M. (2015). Health related quality of life in patients with actinic keratosis–an observational study of patients treated in dermatology specialist care in Denmark. Health and quality of life outcomes, 13(1), 111. Available online at https://www.researchgate.net/publication/280588047_Health_related_quality_of_life_in_patients_with_actinic_keratosis_-_an_observational_study_of_patients_treated_in_dermatology_specialist_care_in_Denmark
(5) Chia, A., Lim, A., Shumack, S., & Moreno, G. (2007). Actinic keratoses. Available online at https://www.racgp.org.au/afpbackissues/2007/200707/200707chia.pdf
(6) Dodds, A., Chia, A., & Shumack, S. (2014). Actinic keratosis: rationale and management. Dermatology and therapy, 4(1), 11-31. Available online at https://www.researchgate.net/publication/260810010_Actinic_Keratosis_Rationale_and_Management
(7) Akarsu, S., & Kamberoglu, I. (2017). Cryotherapy for Common Premalignant and Malignant Skin Disorders. In Dermatologic Surgery and Procedures. IntechOpen. Available online at https://www.researchgate.net/publication/323467478_Cryotherapy_for_Common_Premalignant_and_Malignant_Skin_Disorders
(8) Krutmann, J., Bouloc, A., Sore, G., Bernard, B. A., & Passeron, T. (2017). The skin aging exposome. Journal of dermatological science, 85(3), 152-161. Available online at https://www.jdsjournal.com/article/S0923-1811(16)30816-7/pdf
(9) Latha, M. S., Martis, J., Shobha, V., Shinde, R. S., Bangera, S., Krishnankutty, B., … & Kumar, B. N. (2013). Sunscreening agents: a review. The Journal of clinical and aesthetic dermatology, 6(1), 16. Available online at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3543289/
(10) McIntyre, W. J., Downs, M. R., & Bedwell, S. A. (2007). Treatment options for actinic keratoses. American Family Physician, 76(5). Available online at https://pdfs.semanticscholar.org/5930/8ba596ae2a5a87956977cec2923741c01a20.pdf