New-Onset Guttate Psoriasis: A Long-Term Follow-Up Study.

Background: Guttate psoriasis (GP), a distinct variant of psoriasis, is more common in children and adolescents. The long-term course of these patients has sparsely been examined, with few studies reporting the rates of relapse, persistence, and further development of the psoriasis vulgaris phenotype.

Objectives: The objective of this study was to characterize the long-term outcomes of new-onset GP and elucidate the potential factors associated with a persistent disease course.

Methods: This was a retrospective cohort study. Patients diagnosed with new-onset GP between 2009 and 2020 with a follow-up period of at least 1 year, were enrolled. The examinees were evaluated by dermatologists. Detailed data retrieved from the examinees' medical files included demographics, disease characteristics, treatment, and comorbidities. A structured telephone questionnaire was used to determine the current psoriasis status: type, severity, and extent. At the end of follow-up, patients with a persistent disease course, defined as having lesions at least a year after disease onset, were compared with patients in complete remission without further psoriasis symptoms.

Results: A total of 120 patients (mean age 28.8 years [±15.2], 58.3% women) with new-onset GP flare were identified. At the end of follow-up period (mean 6.2 years [±3.1]), 49.1% (n = 59) of the patients reported active persistent psoriasis. A switch to the psoriasis vulgaris phenotype occurred in 17.5% (n = 21) of the study cohort. Persistent psoriasis was associated with male sex (OR = 2.1, p < 0.05), multiple disease flares (>3; OR = 9.1, p < 0.001), switch to the vulgaris phenotype (OR = 4.16, p < 0.001), and palmoplantar involvement (OR = 5.2, p < 0.01).

Conclusion: A persistent disease course is common among patients with new-onset GP, with most retaining their guttate phenotype throughout the disease course. Persistency was associated with male sex, multiple GP flares, switching to the vulgaris phenotype, and palmoplantar involvement.