Assessment of 5‐Aminolaevulinic Acid Photodynamic Therapy (ALA‐PDT) in Chinese patients with actinic keratosis: Correlation of dermoscopic features with histopathology

Abstract Objectives The study examines the changes in dermoscopic features of actinic keratosis (AK) after photodynamic therapy, and delineates the association between AK dermoscopic and histopathological findings. Methods A total of 21 patients (23 lesions) with pathologically confirmed actinic keratosis who received 5‐aminolaevulinic acid (ALA) photodynamic therapy (ALA‐PDT) were enrolled. The numbers of PDT treatments were: 1, n = 1; 2, n = 2; 3, n = 10; 4, n = 6; 5, n = 2; 6, n = 2). The dermoscopic features before and after the PDT were compared. Results There were statistically significant decreases in the positive rates of dermoscopic features including scales ( P < 0.001), follicular plugs with whitish halo ( P = 0.013), and red pseudonetwork ( P = 0.022) among patients treated with ALA‐PDT. Dermoscopic feature was significantly associated with pathological grade ( P < 0.001). Histopathological hyperkeratosis was significantly associated with dermoscopic red pseudonetwork ( P = 0.034) and wavy vessel ( P = 0.005). Parakeratosis was associated with wavy vessels ( P = 0.001). For vascular hyperplasia in dermal papillae, the significant correlates included scales ( P = 0.011), follicular plugs with whitish halo ( P = 0.011), red pseudonetwork ( P < 0.001); coiled vessels ( P = 0.003) and rosette sign ( P = 0.004). Wavy vessels was the only feature correlating keratosis pilaris ( P = 0.003). Conclusions The findings of the present study support dermoscopy as having potential to be useful for diagnosing and monitoring of actinic keratosis.