Differential diagnoses of psoriasis
M. Alan Menter, Caitriona Ryan in Psoriasis, 2017
Actinic (solar) keratoses are superficial cutaneous lesions consisting of localized proliferations of atypical epidermal keratinocytes.20,21 Actinic keratoses develop commonly as a consequence of cumulative ultraviolet radiation.20,21 The clinical presentation is typically erythematous scaly macules or papules from 2 mm to 1 cm in diameter (Figure 12.38). They occur predominantly on chronically sun-exposed sites, in fair-skinned individuals.20,21 The face, ears, scalp, hands, and forearms are common sites of involvement (Figures 12.39 and 12.40). Histopathology shows focal parakeratosis, with loss of the underlying granular layer and slightly thickened epidermis with some irregular downward buds. Dermal changes include actinic elastosis, and usually a mild chronic inflammatory cell infiltrate.20
Skin Cancer
Henry W. Lim, Nicholas A. Soter in Clinical Photomedicine, 2018
Solar keratoses are also being noted more frequently on the trunk. In a recent study from Queensland, 61% of people who had a full body examination as part of a population study had lesions on sites apart from the head and neck, hands, and forearms (15). Solar ketaroses appear to be a sensitive indicator of sunlight exposure in people who are predisposed to nonmelanoma skin cancer, both basal cell carcinoma and squamous cell carcinoma (16). Although actinic keratoses have been thought to be precursors of squamous cell carcinoma, a prospective study suggested that fewer than 1:1000 of these lesions is likely to change to a squamous cell carcinoma within a year (17). Up to 25% of these lesions may remit spontaneously within 12 months, particularly in people who have the ability to reduce their sunlight exposure (18). Actinic keratoses are also a clinical indicator of high risk of nonmelanoma skin cancer and may be useful as a surrogate for study of the behavior of these tumors, particularly squamous cell carcinoma (16).
The Epidemiology of Skin Cancer
Henry W. Lim, Herbert Hönigsmann, John L. M. Hawk in Photodermatology, 2007
On the contrary, squamous carcinoma is associated with total lifetime sun exposure (80,82,83). Overall, high occupational exposure is inversely associated with melanoma and directly related to the risk of squamous cell carcinoma (79–83). Late stage solar exposure may play an important role in the development of squamous cell carcinoma, since sunlight exposure just prior to diagnosis is associated with an increased risk of the tumor. Actinic keratoses are well-established precursor lesions and recent sun exposure is connected to their development (84). Actinic keratoses may spontaneously disappear in people who limit solar exposure, and their progression to malignancy seems to require continued exposure to relatively high doses of ultraviolet light.
Patient-reported outcomes in topical field treatment of actinic keratosis in Swedish and Danish patients
Published in Journal of Dermatological Treatment, 2018
Hanna Norrlid, Jenny M. Norlin, Heidi Holmstrup, Irena Malmberg, Karin Sartorius, Henrik Thormann, Gregor B. E. Jemec, Gunnel Ragnarson Tennvall
Actinic keratosis (AK) is a common skin condition caused by cumulative sun exposure (1). Diagnosis is based on histology of clinically suspect lesions, but various imaging technologies are being tested as diagnostic aids (2–6). Some AK lesions spontaneously regress (7), while a minority may progress to squamous cell carcinoma (SCC) (8–10). Single lesions most often appear as a consequence of field cancerization in a generally sun exposed area of the skin (2). AK prevalence has been estimated to between 1.4% and 25% of the population (11–14) and known risk factors are age, cumulative sun exposure, Fitzpatrick skin type and previous AK diagnosis (15,16). Current guidelines mostly recommend active treatment of AK, both to reduce symptoms and to lower the risk of developing SCC (17–19), although Danish guidelines accept “no treatment” as a valid treatment option (20).
Comparing efficacy and safety of potassium hydroxide 5% solution with 5-fluorouracil cream in patients with actinic keratoses: a randomized controlled trial
Published in Journal of Dermatological Treatment, 2022
Ali Salehi Farid, Somayeh Niknam, Kheirollah Gholami, Soheil Tavakolpour, Amir Teimourpour, Maryam Daneshpazhooh, Ali Nili, Arghavan Azizpour, Maryam Nasimi, Hamidreza Mahmoudi
Major treatments for actinic keratosis (AK) include two types: destructive modalities such as curettage, and cryotherapy; and nondestructive agents including topical creams such as 5-fluorouracil (5-FU) cream 5% (1–5). Destructive modalities can be associated with different adverse effects such as dyspigmentation, bulla formation, infection, and scarring (6–11). 5-FU is approved by the U.S. Food and Drug Administration (FDA) for the treatment of AK (12,13). However, 5-FU is associated with erythema, crust formation, and bleeding; its effectiveness decreasing in the long run (14,15). Potassium hydroxide (KOH) is a keratolytic agent that is used in the treatment of skin lesions such as warts, molluscum contagiosum, and plantar callus (16–19). KOH is an effective, safe, and inexpensive drug that can easily dissolve keratin and penetrate skin due to its alkaline nature (20).
Effects of topical piroxicam and sun filters in actinic keratosis evolution and field cancerization: a two-center, assessor-blinded, clinical, confocal microscopy and dermoscopy evaluation trial
Published in Current Medical Research and Opinion, 2019
Marina Agozzino, Teresa Russo, Chiara Franceschini, Sara Mazzilli, Virginia Garofalo, Elena Campione, Luca Bianchi, Massimo Milani, Giuseppe Argenziano
Actinic keratosis (AK) is considered an “in situ” non-melanoma skin cancer induced by ultraviolet chronic exposure1. In general, several lesions are present in the same subject2, increasing the risk of malignant transformation3. The concept of field cancerization refers to the development of multiple lesions which derive from preneoplastic changes due to a cumulative exposure to carcinogenic agents4. The combined treatment of AK lesions and field cancerization is considered the gold standard in this clinical setting5. In the pathogenesis of AK, an increased activity of cyclooxygenase (COX) enzymes (both COX-2 and COX-1), at the keratinocyte level, plays a relevant role6,7. Topical anti-inflammatory agents, like diclofenac, could improve the evolution of this kind of lesion8. A topical product containing piroxicam 0.8% and sun filters (50 SPF) (ACTX) has been shown to be very effective in reducing AK lesions9–12. Non-invasive tools like dermoscopy and reflectance confocal microscopy (RCM) are considered effective alternatives to biopsy for the characterization of actinic damage and field cancerization13. So far, no data are available regarding the effects of this product on skin modifications evaluated by RCM and dermoscopy at the target lesion sites and on field cancerization.
Related Knowledge Centers
- Dermatology
- Epidermis
- Keratinocyte
- Precancerous Condition
- Ultraviolet
- Skin
- Light Skin
- Indoor Tanning
- Cutaneous Squamous-Cell Carcinoma
- Squamous-Cell Carcinoma