Comparative Analysis of Clinical, Dermoscopic, and Confocal Microscopy Scores for Assessing Severity of Actinic Keratosis

Abstract

Background: Actinic keratosis (AK) is a common UV-induced intraepidermal neoplasm and a precursor to cutaneous squamous cell carcinoma (cSCC). Accurate, non-invasive assessment of AK severity is crucial for early intervention and risk stratification. Objective: To evaluate the relationship between clinical severity of AK, as defined by the Olsen grading scale, and predefined dermoscopic and reflectance confocal microscopy (RCM) features. Methods: This cross-sectional study enrolled 50 patients with clinically diagnosed AK at a tertiary dermatology center between April 2024 and July 2025. Each lesion was assessed clinically using the Olsen scale (grades 1-3), dermoscopically (five features scored 0-3; total score 0-15), and via RCM (five RCM parameters scored 0-3; total score 0-15). Statistical correlations between clinical grade and imaging features were analyzed using Pearson's χ² test with effect size metrics. Results: Diffuse erythema (p < 0.001), micro-erosions (p = 0.002), strawberry pattern (p = 0.038), and scales (p = 0.012) correlated significantly with Olsen grade, whereas vessels (p = 0.566) did not. All five RCM parameters showed strong associations with clinical severity. Composite dermoscopic and RCM scores correlated with Olsen grade (both p < 0.001). Abnormal honeycomb pattern, parakeratosis, inflammation, and solar elastosis were the best RCM predictors of high dermoscopic severity (all p < 0.001); conversely, erosions, erythema, and scales were the strongest dermoscopic predictors of high RCM severity (all p < 0.001). Conclusions: This study demonstrates strong, statistically significant associations between clinical, dermoscopic, and confocal features of AK. This supports the integration of multimodal scoring into unified AK severity frameworks.

Keywords: actinic keratosis; dermoscopy; non-invasive diagnosis; reflectance confocal microscopy.

Figure 1

Study design and multimodal scoring system for AKs. Eligible patients met inclusion criteria and were assessed clinically (Olsen scale), dermoscopically, and by RCM. Both dermoscopic and RCM evaluations included five predefined features, each scored 0–3, for a maximum of 15 points per modality of evaluation. Image created in CanvaPro.

Figure 2

Case 1. (A) Actinic keratosis clinical aspect—Grade Olsen 2; (B) actinic keratosis dermoscopic score 7 (erosion—2 points, fine wavy vessels—2 points, strawberry pattern—1 point, erythema—1 point, scale—1 point); (C,D) actinic keratosis confocal microscopy score 4 points (abnormal honeycomb pattern 1 point, inflammation 1 point, elastosis 1 point, parakeratosis 1 point, cellylar atypia 0 points).

Figure 3

Case 2. (A) Actinic keratosis clinical aspect—Grade Olsen 2; (B) actinic keratosis dermoscopic score 6 (erosion—0 points, fine wavy vessels—3 points, strawberry pattern—1 point, erythema—1 point, scale—1 point); (C,D) actinic keratosis confocal microscopy score 5 points (abdnormal honeycomb pattern 2 points, inflammation 1 point, elastosis 2 points, parakeratosis 0 points, cellylar atypia 0 points).

Figure 4

Case 3. (A) Actinic keratosis clinical aspect—Grade Olsen 3; (B) actinic keratosis dermoscopic score 11 (erosion—3 points, fine wavy vessels—1 point, strawberry pattern—1 point, erythema—3 points, scale—3 points); (C,D) actinic keratosis confocal microscopy score 10 points (abdnormal honeycomb pattern 3 points, inflammation 2 points, elastosis 2 points, parakeratosis 2 points, cellylar atypia 1 point).