Patients with hypertrophic photoaging appear to have greater general sallowness and greater elastotic material than individuals with atrophic photoaging. These characteristics and many others were identified in the results of a small study published in the Journal of the American Academy of Dermatology.
A total of 53 patients who were evaluated by a dermatologist and classified as having primarily atrophic photoaging, hypertrophic photoaging, or neither were enrolled. Questionnaires were administered to obtain data on participants’ demographics, as well as sun exposure. Histologic and gene expression assessments were performed using biopsies taken from the facial sites of clinically evident photoaging. The investigators qualitatively or quantitatively scored 15 clinical features in each participant.
Relative to the hypertrophic photoaging group, participants in the atrophic photoaging group had greater seborrheic keratosis (mean, 1.6+0.4 lesions vs 4.3+1.0 lesions, respectively; P =.025), lesion counts (mean, 1.2+0.5 vs 8.8+3.1, respectively; P =.001), and previous skin cancer incidence (P =.002). The hypertrophic group had greater general sallowness than the atrophic (P =.005) and control groups (P =.004). Atrophic photoaging participants also had less elastotic material (19% vs 65%). The presence of aberrant elastic fibers was more prominent in participants in the hypertrophic vs the atrophic group (P =.009). No differences were observed between groups in terms of gene expression of matrix metalloproteinases and collagens.
Study limitations cited by the researchers included the small sample size and the lack of assessment of other subtypes of photoaging.
The reasons for the differences observed between hypertrophic and atrophic photoaging “may ultimately reflect fundamental differences in the responses of skin to sun exposure,” the researchers wrote.
Sachs DL, Varani J, Chubb H, et al. Atrophic and hypertrophic photoaging: clinical, histological, and molecular features of two distinct phenotypes of photoaged skin [published online April 4, 2019]. J Am Acad Dermatol. doi:10.1016/j.jaad.2019.03.081