Long-Term Course of Polymorphic Light Eruption: A Registry Analysis

Abstract

Background: Little is known about the long-term course of polymorphic light eruption (PLE).Objective: To predict disease course, a questionnaire was sent to patients whose PLE had been diagnosed between March 1990 and December 2018 and documented in the Austrian Cooperative Registry for Photodermatoses.Methods: In January 2019, 205 PLE patients were contacted by mail and asked to complete a questionnaire on their disease course, including whether the skin's sun sensitivity had normalized (i.e., PLE symptoms had disappeared), improved, stayed the same, or worsened over time. Patients who reported normalization of sun sensitivity were asked to report when it had occurred.Results: Ninety-seven patients (79 females, 18 males) returned a completed questionnaire. The mean (range) duration of follow-up from PLE onset was 29.6 (17–54) years for females and 29.4 (16–47) years for males. The disease disappeared in 32 (41%) females after 17.4 (2–41) years and in 4 (24%) males after 11.8 (5–26) years. Twenty-nine (37%) females and 6 (35%) males reported improvement of symptoms over time; 15 females (19%) and 7 males (41%) reported no change; and 3 females (4%) and no males reported worsening of symptoms. Kaplan-Meier analysis revealed that after 20 years 74% (95%CI, 64–82%) of patients still suffered from PLE. PLE lesion persistence (>1 week) tended to predict a prolonged course of PLE.Conclusions: PLE usually takes a long-term course over many years though in most patients its symptoms improve or disappear over time. How improvement relates to the pathophysiology of the disease remains to be determined.

Demographics and clinical presentations of 844 patients with light and dark skin types with polymorphous light eruption and chronic actinic dermatitis evaluated over 23 years

“…The prolonged and relapsing course of this condition has been highlighted in a recent study involving 97 PMLE patients. Though a majority of these patients experienced improvement, it took 25 years until one third of patients had resolution of PMLE 17 …”

Accumulation of Cytotoxic Skin Resident Memory T Cells and Increased Expression of IL-15 in Lesional Skin of Polymorphic Light Eruption

“…Patients suffering from PLE experience peculiar recurrences of the disease after sun exposure every year in spring or summer. In fact, results of a recent registry analysis of PLE patients indicate that, out of 97 patients analyzed, 74% of the patients still suffered from PLE 20 years after the first eruption, with the lesions often persisting for more than a week during disease episodes (19). However, the pathophysiology behind the prolonged course of the disease has remained unknown.…”

“…This often results in a reduced likeliness of developing lesions and/or less severe clinical manifestations (17,18). However, this photohardening (natural and/or artificial) effect is lost during winter, and PLE patients develop lesions again the next year, continuing to do so for many years to come (19,20). This indicates that a specific disease memory is formed during the active stage of the disease (21), and that such a disease memory might be retained by the skin, favoring the recurrence of the disease.…”

A postulated model for photoimmunopathogenesis of chronic actinic dermatitis around adaptive immunity, including Th17 cells, Tregs, TRMs, cytotoxic T cells, and/or common‐γ chain receptor+ cells

“…As in the early days, CAD was suggested to be an immune‐mediated disease generated by photo‐induced endogenous cutaneous allergens exhibiting a type IV hypersensitivity reaction 13 . The link between susceptibility to UVR‐induced immunosuppression and PLE development, and the pathogenic resistance to UV‐induced immune suppression in patients with PLE are highlighted in recent reviews 14,15 . Contrastingly, the photosensitivity manifestations have a striking difference in duration between patients with CAD and patients with PLE; the former lasts for longer than 3 months and the latter has an evanescent nature with a normal duration of 1–14 days, and comparably, a photoinduced “neo/auto‐antigen” is formed due to a failure in apoptotic cell clearance associated with genetic defects as with PLE patients 16,17 …”

“…13 The link between susceptibility to UVR-induced immunosuppression and PLE development, and the pathogenic resistance to UV-induced immune suppression in patients with PLE are highlighted in recent reviews. 14,15 Contrastingly, the photosensitivity manifestations have a striking difference in duration between patients with CAD and patients with PLE; the former lasts for longer than 3 months and the latter has an evanescent nature with a normal duration of 1-14 days, and comparably, a photoinduced "neo/auto-antigen" is formed due to a failure in apoptotic cell clearance associated with genetic defects as with PLE patients. 16,17 Under the influence of UVR on normal healthy human skin, the adaptive immune response is suppressed by the action of immunosuppressive cytokines (IL-10, IL-4, and TNFα) along with the increased infiltration of neutrophils, Tregs, and mast cells.…”